LA-9256-PR Progress Report
UC-28 LA—9256-PR Issued: March 1M2 DE82 013753
Progress at LAMPF July—December 1981 Clinton P. Anderson Meson Physics Facility
Editor
John C. Allred
Scientific Editorial Board
Olin B. van Dyck Richard L. Hutson M. Stanley Livingston Mario E. Schillaci
Production Staff
Kit Ruminer Beverly H. Talley
so'eij t>y an agency o' the United Slates Govetnin Nether th.. tJf-HW S-dt« Govf.tr •nrv ihetijol. nor .iny a( The,r employees, 'mln, warrjnl/. cuproK necessir-iiy state w ipdeci those of i r*ii' ABSTRACT Progress at LAMPF is the semiannual progress report of the MP Division of the Los Alamos National Laboratory. The report includes brief reports on research done at LAMPF by researchers from other institutions and Los Alamos divisions. Los Alamos National Laboratory Mmm Los Alamos, New Mexico 87545 WSTJBBI/r/ow lyj^mm,* Time to Think about the Future: LAMPF continues to increase its capabilities and productivity. Experimenters are asking ever more sharply defined questions and experiments are becoming increasingly illuminating. The rate of accomplishment is high, but strongly limited by budgets for research and operations. This state of affairs is expected to continue through the rest of this decade. However, now is the time to start giving serious thought to the direction of nuclear physics generally, and LAMPF activities in particular — during the 1990s. The vast world-wide effort on weak interactions is almost guaranteed to open new doors for pur suing the study of nuclear as well as subnuclear physics. Quark physics appears to be here to stay. Low-energy pion probes are proving extremely powerful, and high-energy ones hold similar promise, as do kaons and antiprotons, for opening new windows on the atomic nucleus. So what shall we do to assure the nation a high level of accomplish ment in nuclear physics next decade and perhaps the one beyond that? A serious effort has commenced to explore the options available to us if we use LAMPF as an injector for a higher energy accelerator. Studies are being pursued, workshops are being held, and attempts are under way to elicit the wishes and enthusiasms of the scientific community, upon whom our nation depends for producing the knowledge and people for coping with all matters nuclear. Your input is urgently re quired. Without it, nothing will happen. Louis Rosen Director, LAMPF iv mOCMEM AT LAMPF July-December 1981 Los Alamos National Laboratory CONTENTS EXPERIMENTAL AREAS viii LAMPF ORGANIZATION CHART x I. LAMPF NEWS 1 II. MEETINGS 5 III. RESEARCH 12 Nuclear and Particle Physics 12 Measurement of Parity Violation in the p-Nucleon Total Cross Sections at 800 MeV (Exp. 634) 12 Measurement of the Relative Sign of Neutron and Proton Transition Matrix Elements in (p,p) Reactions (Exp. 627) 14 A Test of the Interacting Boson Approximation (Bates Linac Exp. 782) 14 Electron Scattering from the Oxygen Isotopes (Bates Linac Exp. 756) 15 Structure of States in the Oxygen Isotopes via Measurements of the Spin-Depolarization and Spin-Rotation Observables (Exp. 643) 15 Measurement of the Triple-Scattering Parameters D, R, A, R', and A' for Proton-Proton and Proton-Neutron Scattering at 500 and 800 MeV (Exp. 392) 15 Measurement of Spin-Flip Probabilities in Proton Inelastic Scattering at 800 MeV and Search for Collective Spin-Flip Modes (Preliminary Survey) (Exp. 411) 18 ~p + Nucleus Elastic Scattering at 500 MeV (Exps. 425/433) 19 The nC{p,p'),2C Reaction at 400, 600, and 700 MeV (Exps. 432/531) 22 Excitation of the Giant Resonance Continuum with Intermediate-Energy Protons (Exp. 473) 23 Proton Scattering from 20Ne at 0.8 GeV (Exp. 475) 25 Polarized Proton Scattering from 24,26Mg at 0.8 GeV (Exp. 476) 28 Precision Studies of p + p —*• d + n+ as Probe of Dibaryon Resonances (Exp. 508) 30 p-p Elastic Scattering at 800 MeV (Exp. 563) 32 Search for Giant Monopole and Giant Magnetic Dipole Excitations at 0° (Exp. 630) 34 Reactive Content of the Optical Potential at 800 MeV (Phase II) (Exp. 642) 35 Asymmetry Measurement of the (P.TI1) Reactions on 'Be at 650 MeV (Exp. 649) 37 j^-Nuclear Elastic Scattering at Energies Between 30 and 80 MeV (Exp. 561) 38 A Search for Nuclear Critical Opalescence Using the Reaction 40Ca(jt+,2Y) (Exp. 541) 38 July-December1981 MWOIWM AT LAMPF V Los Alamos Nitiorml Libortlory Elastic Scattering of Pions in the Energy Range 20-50 MeV (Exps. 29/54) 40 Study of Isovector Giant Resonances with Pion Charge Exchange (Exps. 412, 525, and 607) 41 High-Resolution Study of (Jt\/>p). (n\pd), and Other (Tt\.v.v) Reactions on MLi, 14N. and 160 (Exp. 315) 48 A Study of Neutrino-Electron Elastic Scattering (Exp. 225) 49 A Measurement of the Rare-Decay n° —» eV (Exp. 222) 50 High-Precision Study of the uH Decay Spectrum (Exp. 455) 53 A Measurement of Inclusive Pion Double Charge Exchange on "'O and 40Ca (Exp. 309) 55 Preliminary Report on a New Pion-Beta Decay Experiment (Exp. 32) 58 Crystal Box Experiment (Exps. 400/445) 59 Muonic X-Ray Study of "'Am and M5Am (Exp. 653) 61 Inelastic Pion Scattering by 170, '"O, and "F (Exp. 369) 62 Elastic Scattering of Pions from l2,,4C at 164 MeV in 1° Bins (Exps. 539/622) 63 N — Z Dependence of Analog Double-Charge-Exchange Reactions (Exp. 606) 64 Investigation of the Strong Cancellations of Neutron/Proton Transition Amplitudes in 14C (Exp. 622) 65 Nonanalog Double Charge Exchange (Exp. 577) 66 The Study of Broad-Range Pion Inelastic-Scattering Spectra (with Emphasis on the Excitation of the Giant Monopole Resonance) (Exp. 597) 67 Nuclear Chemistry 68 A Product Recoil Study of the "Cfn* ,nN)"C Reactions over the Energy Range 90 to 350 MeV (Exp. 543) 68 Helium-Jet Transport of Fission and Spallation Reaction Products (Exp. 629) 69 Materials Science 71 Irradiation of Technologically Important Metals with 800-MeV Protons Using the Isotope Production Facility at LAMPF (Exp. 554) 71 Muon-Spin-Rotation (uSR) Studies in Spin-Glass Systems (Exp. 499) 72 Models for u+ Depolarization in Spin Glasses 73 Fusion Materials Neutron Irradiations (Exp. 545) 73 The Effect of Dislocation Vibration on Void Growth in Metals (Exp. 407) 74 Muon-Spin-Rotation (uSR) Measurements in Selected Ternary Metallic Compounds (Exp. 640) 75 Biomedical Research 78 Pion Therapy Beam Development and Characterization (Exps. 270 and 271) 78 Treatment-Planning Code Development 79 Biomedical Instrumentation 79 Calculational Support 80 MP-Division Publications 83 Vi PUMREM AT LAMPF July-December 1981 Los Alamos National Laboratory FACILITY AND EXPERIMENTAL DEVELOPMENT 91 ACCELERATOR OPERATIONS 100 MILESTONES 102 APPENDIX A EXPERIMENTS RUN 104 APPENDIX B NEW PROPOSALS 109 APPENDIX C ACTIVE AND COMPLETE EXPERIMENTS BY CHANNEL 112 APPENDIX D ACTIVE SPOKESMEN, INSTITUTIONS. AND EXPERIMENTS 143 APPENDIX E VISITORS TO LAMPF 146 INFORMATION FOR CONTRIBUTORS 151 ERRATUM 152 PROGRESS AT LAMPF Vtf Los Alamos National Laboratory Experimental Areas Primary beam lines in experimental areas: Line A — Main Beam Line for Pion and Muon Channels Line B — Neutron and Proton Beams and Nuclear Chemistry Facility Line C —High-Resolution Proton Spectrometer Line D — Weapons Neutron Research Facility Experimental beam lines: Area A: BSA - Beam Stop A EPICS — Energetic Pion Channel and Spectrometers LEP — Low-Energy Pion Channel P3 — High-Energy Pion Channel SMC — Stopped Muon Channel TTA - Thin Target Area Area B (AB or Nucleon Physics Facility): BR - Neutrons and Protons EPB — External Proton Beam LB-NC — Line B — Nuclear Chemistry Area C: CCH — Area C Control and Counting House HRS — High-Resolution Proton Spectrometer Area A-East: Biomedical Pion Channel TA-5 - Target A-5 ISORAD — Isotope Production and Radiation Effects Facility Neutrino Area ViH MWQRESS AT LAMPF July-December 7981 Los Alamos National Laboratory BEAM AREA X> L1 20 40 60 C I • 1 U 1 1 1 *\4 V DS GCOPMl- yAU in FEE' ,' 'rf^ ff.NUCLNUCLEO N PHYSICS FACILITY BEAM STOP EPICS PION SPECTROMETER TARGET (>,• ^-v? /. . /• ^*-a ,« ""«• HIGH ENERGY PION "» /. • / •• CHANNEL FUTURE STAGING AREA -\\ ..•> * .••'" ' lp,l / HIGH RESOLUTION #^ • Z "' 1 !. SPECTROMETER / V.'" ; V TARGET FUTURE ,A^ A-5 - •'• x ISOTOPE REMOTE KANDLNG.•<#=> 1 PROtXJCTION FACILITY ~j — 4,.J_ a BEAM ?• J, KAD1ATION , „ EFFECTS SWITCHYARD -,. ... ! • .-. ^TARGET VTARGET ;-•** 2 m •Ss . ._ ..''-' , C *"' • V »" ^BEAM STOP N 1 A-6 THIN r "'' - 3* Kali 1 <';^*^«fc^-iF w ft NEUTRINO AREA SUA ! - STOPPED MUON FUTURE STORAGE LOW ENERGY CHANNEL RING AREA PION LINE (LEP) v RADIOBIOLOGY AND THERAPY RESEARCH FACILITY BEAM AREA V »»;« 'X CLINTON P. ANDERSON MESON PHYSJCS rACILITY (LAMPF) WEAPONS NEUTRON > RESEARCH FACILITY TARGET * 1 lL©§MMm® turn IT iwn 1—nimi July-December 1981 PROGRESS AT LAMPF IX Los Alamos National Laboratory LAMPF Dircctor Assoc. Division Leader MP-Division Leader Chit* ol Operation! Louis Rosen Assoc. Division Leader D. C. Hagerman Deputy MP-Division Leader Experimental Areas D. E. Nagle L. E. Agnew Accelerator Development LAMPF Scheduling Experimental Area* Committee Committee Development Committee D. C. Hagerman, Chairman D. C. Hagerman, Chairman L. E. Agnew, Chairman Group IIP-1 , Group MP-2 Aeat. Division Leader Asst. Division Leader Group MP-7 Group MP-1 Electronic Inetrumenta- , Accelerator Operation* Facility Planning • LAMPF Safety Experimental Areas Electronic Instrumenta lion * Computer Syatema ' Budget Control tion I Computer Systems E. W. Hoffman J J. Bergstein R. F. Warner D. R. F. Cochran L. E. Agnew E. W. Hoffman I . Group MP-a | Group MP-11 Aaat. DKriaion Leader Asst Division Leader Group MP-10 Group MP-» Engineering Support • Accelerator Support Experiment Evaluation Users Safety Officer HRS l EPICS Engineering Support 1, LAMPF Uaers Liaison E. D. Bush , J. D. Wallace J. N. Bradbury (Acting) D. R. F. Cochran H. A. Thiessen £. D. Bush Group MP-3 Group MP-4 Group MP-13 Applicationi- Oriented Nuclear t Particle Beam-Line Development Research Physics J. N. Bradbury D. E. Nagle R. J. Macek LAMPF ORGANIZATION February 1982 PROGRESS AT LAMPF JULY — DECEMBER 1981 CLINTON P. ANDERSON MESON PHYSICS FACILITY I. LAMPF NEWS • Summer brings many visitors to LAMPF. Pictured New York at Stony Brook), Dirk Walecka (Stanford are some who were present in August: Vernon Hughes University), and R. R. Wilson, formerly Director of Fer- (Yale University), Earle Lomon (Massachusetts Institute milab, now Pupin Professor of Physics at Columbia Uni- of Technology), Fred Goldhaber (State University of versity. Vernon Hughes, Yale University Fred Goldhaber, State University of New York at Stony Brook July-December 1981 PROGRESS AT LAMPF 1 Los Alamos National Laboratory Earle Lomon, Massachusetts Institute of Technology Dirk Walecka, Stanford University R. R. Wilson, formerly Director of Fermilab, now Pupin Professor of Physics at Columbia University 2 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Translation: FANG YI MEETS U.S. FAMOUS NUCLEAR SCIENTIST, DR. ROSEN NewChina News Agency Telegraph, October 10, Peking: #*£fc£SBS«tta¥«**± Vice Premier Fang Yi met this afternoon at Tze-Quan (Violet Light) Hall in Zhong-Nan-Hai (Mid-South Sea) ||II£»rP!r&JS»fS:&# with the head of the (medium-energy) physics division of Los Alamos National Laboratory, USA, famous nuclear ±SJ*A. scientist Dr. Rosen and his wife. • Louis and Mary Rosen visited China September 25-October 19, 1981. They are shown with Vice Premier Fang Yi (center), whose responsibilities include science, technology, and education. The Rosens renewed friendships with two Chinese physicists who visited LAMPF in May 1980. They are Li Shounan (front row, left) and Ding Dazhao (back row, right). • Danny Doss and Dick Hutson (both in Group MP-3) Dean A. McGee Eye Institute and the Department of have a new algorithm for computing corneal shape. Ophthalmology at the University of Oklahoma, says the arrived at serendipitousiy over coffee. A photograph of tcchnii]iic is something eye specialists have been seeking the corneal reflections of concentric rings can be without success for the past 100 years. "The Los Alamos analyzed to yield information on distortions of the eor- technique is a bridge that has filled a gap in nea. J. James Rowsey, chief of corneal surgery tit the ophthalmology." Rowsey concludes. "We can now July-December 1981 PROGRESG AT LAMPF 3 Los Alamos National Laboratory Darnv Doss and Dick Hutson monitor patients before and after surgery or corrective Several other people senior in service at LAMPF also lens fitting, to define the success of the therapy and make opted for voluntary separation. These include Mary continuing corrections as needed." Riggs and Kitty Maraman in the Division Office, Lois • The voluntary separation program at the Laboratory Rayburn in the Operations Office, Pauline Ungnade in has caused major changes in the administrative structure the Safety Office, Garrison H. French of Group MP-13, at LAMPF. T. M. Putnam, Assistant Division Leader and Joe Katcher of Group MP-11. for LAMPF Safety, will retire as of February 1982. • Linda Tyra, supervisor of the LAMPF Visitors Cen Donald R. F. Cochran will exchange his duties as Assis ter for the past 2 years, married Andrew Bacher on tant Division Leader for Experiment Evaluation and December 20, 1981. The Bachers will make their home LAMPF Users Liaison for those that Tom Putnam relin in Bloomington where Andy is Professor of Physics at quishes. James N. Bradbury, on an acting basis, assumes Indiana University. the position vacated by Cochran. The LAMPF organiza tion chart in this issue reflects these changes. 4 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory II. MEETINGS LAMPF Users Group, Inc. Angeles, is the Chairman elect. Other new members of the Hoard .>f Directors arc George A. Cowan, Los Fifteenth LAMPF Users Group Alamos, and Norton M. Hintz. University of Minnesota. Annual Meeting Members whose terms continue in 1982 arc Harold E. Jackson, Argonnc National Laboratory. Chairman; The LAMPF Users Fifteenth Annual Meeting was F'elix H. Bochm. California Institute of Technology. Past held in Los Alamos on November 2 and 3 with 2Id at Chairman; Ernest J. Moniz, Massachusetts Institute of tendees. Chairman Felix Bochm (California Institute of Technology: and L. Wayne Swenson, Oregon State Un Technology) presided at the opening session, which in iversity. The remainder of the afternoon session was cluded a welcoming address by Donald M. Kerr, Direc ('cvoted to talks by Jean-Pierre Blaser. Director. Swiss tor of the Los Alamos National Laboratory. Clarence R. Institute for Nuclear Research, who spoke on "SIN: Richardson, Division of Nuclear Physics. Office of Status, Future Scientific and Technological Plans;" Milla Fncrgy Research of the Department of Energy, presen Baldo Ceolin, University of Padova-CERN, who dis ted "A Report from Washington." A report on the status cussed "Neutron Oscillations;" and Alex Zchnder. ETH- of LAMPF was given by Louis Rosen, Director of Zurich. who reported on "The Hunting for the Axion." LAMPF, and Donald C. Hagcrman. Chief of Opera The Tuesday morning session, presided over by tions, reported on LAMPF operations. The second por Robert Eiscnstcin. Carnegie-Mellon University, was tion of the morning session was devoted to New Direc devoted to reports by Robert Redwinc, Massachusetts tions. with reports by Gerard J. Stephenson entitled Institute of Technology, who spoke on "Searches for "Progress Report on a Proposal for a Los Alamos Violation of Muon Number Conservation;" George A. Neutrino Facility;" Darragh E. Naglc. "Progress Report Rinkcr, Los Alamos, who reported on "Current on a Kaon Factory;" and Henry A. Thiessen, "Em Problems in Muonic Atom Physics;" and David J. Ernst, bryonic Plans for Kaon Factory Experimental Areas." Texas A&M University, who discussed "Recent Results The afternoon session was conducted by incoming in the Pion-Nucleus Interaction." Chairman Harold E. Jackson, Argonne National The remainder of the day was devoted to working Laboratory, and included the Annual Users Group group meetings. A ro"nd table discussion of "Planning Report by Felix Boehm. The results of the election were for a Kaon Factory" was held in the evening. given; George J. Igo, University of California, Los The 1982 Working Group Chairmen are as follows: Stopped Muon Channel (SMC) Gary Sanders Los Alamos Solid-Slate Physics Robert Brown Los Alamos and Materials Science Neutrino Facilities Herbert Chen University of California. Irvine Muon Spin Rotation Richard Hutson Los Alamos Nuclear Chemistry Bruce Dropesky Los Alamos Biomcd James Bradbury Los Alamos Nucleoli Physics Laboratory (NPL) Lawrence Pinsky University of Houston Polarized Facilities Michael McNaughton Los Alamos Energetic Pion Channel and Donald Geesaman Argonnc Spectrometer (EPICS) Computer Facilities Michael McNaughton Los Alamos High-Energy Pion (P') Channel Hans Plcndl Florida State University Low-Energy Pion (LEP) Channel Barry Ritchie University of South Carolina High-Resolution Spectrometer (HRS) John McGill Rutgers University Graduate Student/Postdoc John Faucett University of Oregon n° Spectrometer Helmut Baer Los Alamos July-December ^ 9BI PROGRESS ATLAMPF 5 Los Alamos National Laboratory Technical Advisory Panel anticipated needs for improvements and maintenance for beam lines was outlined, contingent on budgetary Chairman Felix Bochm, California Institute of restraints. The TAP strongly recommends that LAMPF Technology, presided at the meeting of the Technical operations should strive for a 1-mA beam. Advisory Panel (TAP) on Wednesday, November 4, Richard Boudrie gave an update on the LEP spec 1981. Louis Rosen spoke to the group, expressing trometer. The TAP still holds the opinion that it is over- cautious optimism regarding the LAMPF budget out designed and asked that a subcommittee be formed to look. Budgetary restrictions continue to be a prime con review the proposal. Cyrus Hoffman, Los Alamos, and cern. A production schedule of about 24 weeks is still Wayne Swenson, Oregon State University, will study the projected if appropriate funding is obtainable. Rosen ex proposed design and also look into the possibility of an pressed concern that should a "worst case" budget situa EPICS II. tion evolve, the resulting limited period of operations Robert Macek and H. A. Thiessen, Los Alamos, dis might seriously affect the biomedical program. The cussed the proposal for the development of a dispersed 6 months' shutdown periods are not regarded with favor beam for the P' channel. The TAP requested a clear by the TAP. statement of requirements to be presented at the next Rosen commented on the developing VAX computer Board of Directors/TAP meeting. system with its possibility that Users might be able to David Vieira. Los Alamos, gave a progress report on access the system from their home institutions when it the Time of-Flight (TOF) spectrometer, outlining the becomes fully operational, possibly within a year. This proposal that it be placed in the present location of the effort will be reviewed at the next TAP meeting. Area A basement shop, which would increase the cost by Donald C. Hagerman presented an optimistic report about SlOOk. Some optics and design problems remain on the Proton Storage Ring (PSR) and polarized ion to be solved. The TAP concurs in this proposal. source activities, stating that these activities have the full Ted Spitzmiller, Los Alamos, discussed the LAMPF support of the Laboratory administration and that the Electronics and Equipment Pool (LEEP) and computer new and innovative projects at LAMPF present a maintenance activities. The staff for computer main challenge to those involved in their development. tenance is limited to ongoing experiments, and the LEEP Wayne Cornelius and Robbie York reported that a management continues to need very early input for large proposal for an optically pumped polarized ion source and/or unusual requests for equipment. The TAP has been submitted to the. LAMPF administration, with recognizes the progress LEEP has made, stresses the a projected cost of $2 million and a completion schedule need for further growth, and deplores the lack of User of 3-4 years. The possibility of a collaboration with KEK response to the definition of needs. (Japan) to develop such a source was investigated. It was A discussion of the neutrino facility was led by Lewis learned that the Japanese are not interested in further Agnew. Cost estimate for a neutrino tunnel to fit the collaboration other than that already established with needs of Proposal 645 was estimated at $5O0-$6O0k with Fermilab, Stanford, and Brookhaven National a time estimate of about 18 months for construction. Laboratory. They seem willing to permit observers to Gerard Stephenson, Los Alamos, stated that the share their technology on a reasonable basis. It should be Laboratory is preparing a proposal for submission to possible to obtain a copy in two or three years at a DOE by January 1982 to accommodate Proposal 638. probable cost of about one million dollars. The TAP feels The BOD/TAP would like to review the proposal before that liaison with KEK should be maintained and George submission but because time will not allow this, Chair Igo, UCLA, will investigate the possibility of closer man Bochtn accepted the responsibility of representing collaboration. BOD/TAP interests. The existing Lamb-shift source is operating reliably H. A. Thicssen, Los Alamos, reported on inputs he with the possibility of a factor of two increase in inten had received regarding LAMPF II. The BOD/TAP sity; however, the polarized-neutron program must be strongly supports efforts leading to a proposal for held back because of the inability to achieve a factor of LAMPF II and recommends implementation of 100 increase in beam current. mechanisms for getting user input and employing user ef Lewis Agnew presented a report of experimental fort. operations and possible future programs. A schedule of 6 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Board of Directors Martin Cooper a/id Ted Spitzmiller presented a num ber of proposals for operating procedures at LEEP. The The Board of Directors of the LAMPF Users Group, TAP is charged with soliciting responses from its Inc., met on Friday, July 31, 1981, with Chairman Felix colleagues on these proposals. Bochm presiding. The Board expressed pleasure with the progress on the Guidelines for the new DOE security procedures for Time-of-Flight Spectrometer reported by David Vieira. visits and assignments of foreign nationals were dis Robert Macck reported on the progress of kaon fac cussed; instructions to spokesmen will be sent out. tory studies. The Board recognizes the need for more dis Louis Rosen provided a review of operations and a semination of information and suggested that more input discussion of future funding possibilities for LAMPF. from universities should be solicited. Several funding options are being investigated which, if approved, would increase LAMPF's running time to 28- 30 weeks of production for the year. A collaborative Board of Directors development effort between LAMPF and KEK in Japan for an optically pumped ion source is being studied. The The Brard of Directors of the LAMPF Users Group, budget for LEEP has been increased to $50$ 100k with Inc., met on Wednesday. November 4. 1981 with Chair an additional increase projected for next year. Rosen man Felix Bochm. California Institute of Technology, stressed the need for the establishment of a dedicated presiding. Seventeen candidates for the Program Ad constituency in support of a kaon factory, and presented visory Committee (PAC) were selected and their the view formulated by several leaders in this field that nominations sent to Louis Rosen for consideration. there should be one kaon factory in the world and that a Newly appointed or reappointed members of the TAP world-wide collaboration might be sought. are: Felix Boehm reported briefly on the Neutrino Billy E. Bonner (Los Alamos/Rice University) Workshop and stated that a fu!! report of the workshop Thomas J. Bowles (Los Alamos) is being prepared. Gerald Dugan (Columbia University) A shop to meet the needs of Users was discussed and Barry M. Precdom (University of South Carolina). the idea was endorsed by the Board. The TAP is charged Other members who will continue to serve during 1982 with addressing the scope of User shop needs. are: Length of the terms of office of the Board Chairman James F. Amann (Los Alamos) and scope of duties of members of the Board of Direc Herbert H. Chen (University of California, Irvine) tors was discussed. Significant effort is involved; this fact Daniel H. Fitzgerald (University of California, Los should be taken into account by the nominating commit Angeles) tee when it selects a slate of candidates. Robert Heffner (Los Alamos) The following reports were presented: Paul .1. Karol (Carnegie-Mellon University) Lewis Agncw reported on the on-line research being Michael Paciotti (Los Alamos) done at the neutrino facility and the proposed experi William R. Wharton (Carnegie-Mellon University) ments. Problems in connection with the facility will be Benjamin Zeidman (Argonne National Laboratory). reviewed again at the next Board meeting. Robert Eiscnstcin agreed to act as Chairman of the Richard Boudrie discussed the proposed new LEP Nominating Committee. Spectrometer and the projected cost of incorporating The recommendations of the TAP were accepted. some new features. He stated that copies of the Spec The graduate student/postdoc organization remains trometer Workshop meeting are available in the Users interested in continuing their own physics seminars and Office. The Board decided that the final design should be will be supported by LAMPF if they will take the in sent to the Technical Advisory Panel early enough so itiative. Student representative John Faucett will be con that it can be discussed at the November meeting. tacled. Wayne Cornelius elaborated on the optically pumped The Board of Directors is quite interested in studies ion source work. The Board feels that the development for LAMPF expansion and improvement (LAMPF II) collaboration with TRIUMF and KEK should be pur and recommends a strong advocacy role from the User sued, and that the LAMPF level of effort should be community. Additonal Board of Directors meetings will strengthened. be scheduled to monitor LAMPF II progress. July-December 1981 PROGRESS AT LAMPF 7 top Alamos National Laboratory The incoming Chairman, Harold Jackson, will con periments visited LAMPF. Eighty-two were foreign tinue to be concerned with long-range plans and will visitors. A total of 358 check-ins and 400 check-outs emphasize agenda items such as update of LAMPF II were processed by the Visitors Center. A complete list is working group reports, review of neutrino facility attached in Appendix C. proposal, discussion of User involvement, initiation of a Housing requirements for 1981 decreased approx bulletin-type newsletter to foster awareness of LAMPF imately 15% over the previous year. Families housed in in the User community, and continued investigation of LAMPF apartments totalled 2 . students housed totalled the possibility for a social area for LAMPF Users. 61 in efficiency units, and townsite sublets totalled J8. The number of Users in LAMPF efficiency (short-term) units was 584 for the year. In addition, miscellaneous Visitors Center apartment rentals totaled 14, and 145 motel reservations During this report period, 391 research guests work were arranged for visitors. ing on LAMPF-related activities or participating in ex A breakdown of user statistics follows. —M. M. Eutsler •MEMBERSHIP •INSTITUTIONAL DISTRIBUTION Non-Los Alamos National Laboratory 764 Membership by Institutions Los Alamos National Laoratory 191 Los Alamos National Laboratory 191 National or Government Laboratories 97 TOTAL 955 U. S. Universities 382 Industry 47 • FIELDS OF INTEREST Foreign 174 Nuclear and Particle Physics 748 Hospitals 50 Nuclear Chemistry 141 Nonaffiliated 14 Solid-State Physics and Materials Science 185 TOTAL 955 Theory 185 Biomedical and Biological Applications 2.40 Number of Institutions Weapons Neutron Research 98 Naiional or Government Laboratories 23 Data Acquisition 167 U. S. Universities 110 Administration, Coordination, Facilities, Industry 37 Operations, Practical Applications, etc. 156 Foreign 85 Isotope Production 88 Hospitals 40 (Note: These numbers do not add to total membership becaus:ause of Nonaffiliated 7 multiple interests.) TOTAL 302 •REGIONAL BREAKDOWN East (Pennsylvania, New Jersey, Delaware, Washington DC, Massachusetts, New York, Connecticut, Vermont, Rhode Island, New Hampshire, Maine) 135 Midwest (Ohio, Missouri, Kansas, Indiana, Wisconsin, Michigan, Illinois, North Dakota, South Dakota, Nebraska, Iowa, Minnesota) 100 South (Maryland, Virginia, Tennessee, Arkansas, West Virginia, Kentucky, North Carolina, South Carolina, Alabama, Mississippi, Louisiana, Georgia, Florida) 83 Southwest, Mountain (Montana, Idaho, Utah, Wyoming, Arizona, Colorado, New Mexico, Oklahoma, Texas) (excluding Los Alamos) 148 West (Alaska, Hawaii, Nevada, Washington, Oregon, California) 124 Foreign 174 Los Alamos National Laboratory 191 TOTAL 955 8 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory H Workshop spectroscopy of H~ based on the theoretical approach of the Fano school, development of the Schrodinger equa A Workshop on the Physics of H~ was held by the tion in hyperspherical coordinates. Dr. Lin reported on University of New Mexico and Los Alamos National detailed studies he has made of the correlation between Laboratory on November 12, 13, and 14, 1981 at the the two electrons in H~. These correlations were presen Los Alamos Linear Accelerator Facility (LAMPF). The ted as three-dimensional plots, shown in perspective, organizing committee for the workshop was: which demonstrated clearly the tendency for the two J. B. Donahue (Los Alamos) electrons to reside on opposite sides of the proton, and P. A. M. Gram (Los Alamos) how this correlation depends upon the "hyperspherical D. A. Clark (University of New Mexico) radius" (the square root of the sum of the squares of the W. W. Smith (University of Connecticut) individual electron-proton distances). The final paper in H. C. Bryant (University of New Mexico). the "H~ Resonance Structure" session was by David Workshop staff were Linda Tyra and Alice Horpedahl of Herrick, University of Oregon, who presented a group- LAMPF. The workshop was supported by the US DOE theoretic approach to the two-electron atom, which com (Contract DE-AS04-77ERO 3998), Los Alamos pared the structures of helium and H~. Using Lie National Laboratory, and the University of New Mex algebra, Herrick and his coworkers have been able to ico. arrange the states of these two atomic systems into The two-day workshop was divided into four main supermultiplets according to quantum numbers based on sessions, each focussing on a different aspect of the H~ angular momentum and the Lenz vector. Following problem, and included as well a session on related work Herrick's talk, John Nuttall, University of Western On with the parent H° atom. The unifying theme of the tario, called attention to the possibility of large-computer workshop was the on-going experimental work at calculations for the exact determination of energy levels LAMPF, which, by exploiting the relativistic kinematics by "brute force." Gary D. Doolen, Los Alamos, of an 800-MeV H~ beam, has made accessible the described briefly his computations on the Los Alamos resonance region of H~ with unprecedented resolution. National Laboratory CRAY using 816 basis states. The first session, entitled "H~ Resonance Structure," The Thursday afternoon session, entitled "Threshold was chaired by John S. Risley from North Carolina State Laws for H~," chaired by Joe Macek, University of University, who inaugurated the conference with a brief Nebraska, began with a presentation by Joey B. survey of the energies and widths of the H- resonances. Donahue, Los Alamos, on the experimental measure David A. Clark gave a detailed account of the studies at ment at LAMPF of the two-electron photodetachment LAMPF of the photodetachment spectrum of FT, es cross section. The LAMPF group finds results consistent pecially as it bears on the character of the resonances in with the Wannier law. However, the possibility of an os H~. He also described the recent precision measurement cillatory modulation of the cross section near threshold of the energy of the 'P Feshbach resonance below the cannot be ruled out, if the amplitude of the oscillations is n = 2 threshold in H°. By arranging for three harmonics sufficiently small. Donahue also discussed some of the of the YAG laser to produce three separate but carefully methodological discoveries made in perfecting these synchronized beams to intersect the H- beam at three measurements which will be helpful in future work on the different points, it has been possible to measure the H~ structure. Turning to theoretical methods of treating energy of this "touchstone" resonance in H- relative to threshold laws, A. R. P. Rau of Louisiana State Univer the very well known levels in H°. So far, this technique sity briefly reviewed the evolution of threshold laws in has yielded a value for the photon energy required to ex general, and then discussed in detail the Wannier idea of cite this resonance of 10.925 ± 0.002 eV. Experiments dynamic screening and its quantum mechanical implica planned for the spring of 1982 should reduce the uncer tions. One finds, not unexpectedly, that the situation tainty of the measurement to I meV. Discussion follow where both electrons remain equal distances from the ing the talk revealed that this measurement of the proton is favored for the detachment process, but it is Feshbach energy should be sensitive to "mass polariza rather surprising that although the individual angular tion" effects, in which the energy taken up by the momentum states of the electrons must be uniformly dis proton's motion is strongly influenced by the correlation tributed up to very large values, the threshold cross- between the two electrons. The second speaker was Chii- section behavior does not depend upon the total angular Dong Lin, Kansas State University, who discussed the momentum, so the fact that the photoabsorption process July-December 1981 PROGRESS AT LAMPF 9 Los Alamos National Laboratory picks out the L = 1 state is essentially irrelevant. Aaron nearly degenerate 'S state to give a "linear Stark effect" Temkin of NASA/Goddard Space Flight Center presen behavior. As the effective field is increased above ted his approach to the two-electron detachment 400 kV/cm, these narrow states evidently quench, and problem. In contrast to the Wannier result championed noticeable structural changes occur in the 'P shape by Rau, Temkin favors what he terms a "Coulomb- resonance. Also beginning with field values above dipole theory" in which the dominant contribution to the 400 kV/cm, a structure appears in the vicinity of a JD process is one where the energy partition between the resonance lying some 100 meV below the shape two escaping electrons is asymmetric. This approach resonance. The systematics of these measurements were yields a threshold law, which, although it is compared with a simple perturbation theory. The second monotonically increasing with energy above threshold, is talk, by William Reinhardt, JILA, University of subject to possible oscillatory modulations. So far no Colorado, dealt with theoretical methods of treating the computations of the specific form of the threshold law H~ ion in strong electric fields. Reinhardt presented the have been performed, and although its general behavior "complex rotation" method for dealing with perturba can be delineated, there are no estimates of either the size tions by external fields. He went on to discuss recent or periodicity of the putative oscillations. The final semiclassical work in which one quantizes line integrals presentation to the workshop on Thursday was a change around an "invariant torus." Joe Macek, University of in pace going back to a strictly classical treatment of the Nebraska, the next speaker, remarked on the possible two-electron ion by Kenneth Butterfield, a graduate stu implications H" work might have for other three-body dent in the LAMPF group from the University of New problems. An inverse square potential apparently plays a Mexico. Butterfield discussed some results of a computer role in the binding of quarks at short ranges and of + code that generates trajectories of two electrons and a course is operative in such objects as the H2 . Macek proton for various initial conditions. The results were discussed the hyperspherical approach to the three-body presented in a series of binocular colored slides which the problem, in which he was a pioneer, and the problems in audience viewed through special "3-D" glasses. (Most volved in the treatment of long-range Coulomb interac people were actually able to fuse the binocular view into tions. An extensive discussion concerning three-body ef one three-dimensional image.) Butterfield has found that fects followed. K. T. Chung, North Carolina State Un for certain highly symmetrical initial conditions he can iversity, next spoke briefly on his work on the formation get "quasi-stationary" states in which the two electrons of low-lying doubly and triply excited He~ states. remain in the vicinity of the proton. However, for all Peter M. Koch, Yale University, introduced the final other initial conditions he has tried, the atom session, "Symposium on H° in Strong Fields," chaired "autoionizes," with one electron picking up escape by W. W. Smith, with a discussion of his experimental velocity from the other, so that one electron spirals in as and theoretical work on Stark effects in H°. the other spirals out. The "mathematical experiment" After Koch's talk, the workshop was adjourned for leads to the conjecture that, even without radiation, the lunch, after which tours of the linear accelerator were classical multielectron atom is, in principle, unstable. arranged with emphasis on a display of the equipment The third session, on Friday morning, entitled "H~ in used in the H~ studies. Peter Gram gave a brief and en Strong Electric Fields," was chaired by P. A. M. Gram. tertaining slide show introducing LAMPF to the con According to the customs of this workshop, the first talk ference attendees. was a presentation of LAMPF results for H~ in strong Winmrop W. Smith called together the afternoon ses fields by H. C. Bryant. Bryant charted the changes in the sion, which was a continuation of the segment begun by photodetachment spectrum in the vicinity of the n = 2 Koch, "Symposium on H° in Strong Fields," with a brief H~ resonances as a function of electric field. The description of how H° can be produced with near-luminal phenomena evidently involve four resonant structures, velocities (either by stripping or by photodetachment) at two seen in the zero field spectrum because they are 'P„, LAMPF. Subsequently, the same techniques which have and two unseen, because they cannot be excited in a one- been used successfully to study H~ can be applied to H°. photon process. These four seem to form two pairs that In particular, the behavior of the low-lying states of H° dominate the response in separate regimes of electric- can be observed for the first time in very strong fields. field strength. When small fields are applied, the narrow The next speaker was Thomas H. Bergeman, SUNY, :P Feshbach resonance evidently mixes strongly with a Stony Brook, who presented calculations on the effects 10 PBOQM88 AT LAMPF July-December 1981 Los Alamos National Laboratory of strong fields on H°, emphasizing the possibfe interest The organizers wish to thank J. V. Martinez, USDOE; in fluctuations in oscillator strength above threshold. Louis Rosen, Director of LAMPF; Marcus Price, Chair Harris J. Silverstone, Johns Hopkins, next introduced the man, Physics and Astronomy, University of New Mex workshop to the arcane (to many of us) mathematics in ico; and Dean F. Chris Garcia, College of Arts and volved in summing the divergent series in the Stark ef Sciences, University of New Mexico, for their steadfast fect. Charles Clark, National Bureau of Standards, support. They also wish to. acknowledge with many Washington, discussed the spectroscopy of H° in a thanks the Physics and Astronomy secretarial staff at magnetic field, and results of calculations on the CRAY the University of New Mexico for their patience and computer using thousands of Sturmian functions. At 5 T, help. Finally, it must be admitted that the whole one finds an amazingly rich structure in this simplest of workshop would have collapsed without the talents and structures. The final speaker of the workshop was hard work of Alice Horpedahl and Linda Tyra at Munir H. Nayfeh, University of Illinois, who reported re LAMPF. cent work on two-photon spectroscopy in the H° atom. —P. A. M. Gram and H. C. Bryant July-December 1981 MtOQREat AT LAMM 11 Los Alamos National Laboratory III. RESEARCH Nuclear and Particle Physics determine the cross section by measuring the trans mission of the polarized proton beam incident on target. Measurement of Parity Violation in the p-Nucleon A diagram of the experimental layout is shown in Fig. 1. Total Cross Sections at 800 MeV Both detectors are integrating types, specially designed to handle the full polarized proton beam current. By (Exp. 634, EPB) analyzing the signal for a component correlated with the (Los Alamos, Univ. of Illinois) 30-Hz polarization reversal frequency we can determine Spokesmen; R. Carlini andR. Talaga (Los Alamos) and the magnitude of any helicity dependence of the total V. Yuan (Univ. of Illinois) cross section. Auxiliary detec:ors measure systematic contributions that can result in an apparent helicity- The goal of this experiment is to measure the contribu dependent cross section actually unrelated to the weak tion of the weak force to nucleon-nucleon scattering at force. Systematics of this type includes the effects of 800 MeV. Although the scattering is dominated by residual transverse polarization, position motion, inten strong and electromagnetic interactions, the weak in sity modulation, and a phase-space distribution of teraction may be identified by the signature of parity residual transverse polarization. A large part of the ex violation. In this experiment longitudinally polarized periment is dedicated to measuring the sensitivity of the protons are scattered from an unpolarized target, and transmission detectors to changes in these beam charac parity violation manifests itself as a small helicity depen teristics at the 30-Hz polarization reversal frequency. dence in the total cross section. The desirable placement for the beam through the ap The experiment is one of a series of experiments to paratus is along an axis that minimizes the effect of the measure the weak nucleon-nucleon interaction as a func systematic contributions. Before taking any production tion of energy. Calculations of the helicity-dependent data this axis is experimentally determined and the beam asymmetry of the total cross section have been published is located along it to a precision of 0.1 mm. for energies corresponding to those experiments. At 15 Throughout the run, changes in beam properties are and 45 MeV the calculations1"3 are in good agreement minimized when possible. Long-term beam motion and with the experimental results4'5 of ~1 X 10-7. However, 30-Hz intensity modulation were held constant by means at 6 GeV the prediction6 is 0.5 X 10~7 whereas the ex of servo-feedback systems. perimental value7 is (2.6 ± 0.6) X 10-6, more than an or der of magnitude larger. At 800 MeV the Henley and A limiting factor to the sensitivity of the experiment is Krejs calculations6 predict the asymmetry to be ~1 X the noise level of the transmission detectors. To judge the performance of the detectors the noise level is compared io-7. to I~m, where / is the beam current incident on target. The experiment uses the LAMPF polarized proton This noise level corresponds to the noise caused solely by beam at an energy of 800 MeV. Polarization is reversed at a rate of 30 Hz at the injector. Two ion chambers counting statistics in the case of a 50% transmission target. In the early part of this year we worked on a new POSITION SERVO ELECTRONICS SPLIT ION CHAMBER {> .FOR BEAM POSITION SPLIT ION CHAMBER / DETERMINATION .FOR BEAM POSITION J DETERMINATION tKH} T ICI ^ ICZ • *P SCATTERING TARGET STEERINI G POLARIMETER TARGET Fig. J. Schematic of experimental apparatus. 12 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory detector design to decrease the noise level of the trans metry. On the other hand, a thick target increases the mission detectors and to understand the origin of this amount of multiply scattered particles that hit the noise, which in previous runs was ~15 times counting downstream ion-chamber plates, thereby undesirably in statistics. As reported in the previous progress report the creasing noise from spallation. Additionally, close prox source of the noise was spallation products produced in imity of the target to the downstream ion chamber the foils of the ion chambers themselves! Before the July results in reduced chamber noise, but at the same time in run new detectors (with electrodes parallel to the beam) creases sensitivity to polarization systematics. Based on were bi '.A to tolerance levels necessary to reach a sen these considerations a 10-cm HzO target was located sitivity equal to counting statistics. 150 cm in front of the downstream transmission detec During the second half of 1981 the experiment ran for tor. 1 week in July and for another week at the end of As an alternative to producing longitudinally polarized November. The July run was conducted with many new beam by means of the Wien filter located close to the pieces of apparatus. In addition to building new ion source, a first attempt was made in the November run to chambers we developed improved low-noise amplifiers take data by using the superconducting spin-precessing and signal-sampling electronics, a polarimeter for use at solenoid located in the EPB. Use of the EPB precessor to high beam currents, and an automated beam-scanning achieve longitudinal polarization is desirable because it target. A large portion of time spent during the run was allows vertical polarization to be provided to Line C devoted to optimizing the performance of the apparatus. (HRS). As a consequence, a broader range of experi Data were taken primarily with the target out. Both ments can be active in Line C while polarization is slow-reversal (NN and RR) states of the polarized longitudinal in the EPB. Once longitudinal polarization source were examined for consistency in their target-out, was obtained by means of the precessor we were able to helicity-dependent cross-section measurements. There investigate control of residual polarization components was no difference for the two source states within as well as to measure the distribution of residual statistics at a level of 1 x 10~7 in the raw asymmetry. polarization across ihc profile of the beam. The results Using the beam-scanning target we were able for the first show a disturbingly large variation in transverse time to scar, the profile of the beam and map the distribu polarization across the profile of the beam with the spin- tion of residual transverse polarization components precession solenoid on. More study is needed to deter across that profile. Measurement of the polarization dis mine the origin of this effect and to search for a cure. For tribution within the beam is essential to the systematic the remainder of the run the precessor was switched off error analysis of the experiment. A target-out noise level and we returned to the Wien filter as the source for of 1.2 times counting statistics was achieved in the ion- longitudinally polarized beam. chamber transmission detectors. Finally, at the conclu During the November run data were taken in several sion of the run target-in data were also taken, with a ratio target thickness/position configurations. For the first of noise/counting statistics of 4.0. time we were able to gather information regarding the After the July run a model was developed explaining dependence on target position of the experimental sen that the increased noise with the target-in configuration sitivities to systematic contributions. Using the beam- is a result of particles, which are multiple scattered in the scanning target, a profile distribution map of polarization target, hitting the collection plates of the detector and components was made for both NN and RR source con producing spallation products. Calculations based on figurations. As a result of the calculations based on the this model and the data taken in July were made in order July data, large improvement in the target-in noise was to determine optimum target position and thickness for realized and a noise level as low as 1.4 times counting data collection. The choice involved striking a balance statistics was achieved with a 10-cm H20 target. After among several competing considerations regarding target the extensive study and minimization of systematic con thickness and position. For instance, the helicity- tributions for the target-in configuration were completed, dependent change in cross section (Ao/2a) is related to some production data were taken with an average beam the measured change in transmission (AT/2T) by a fac current of 2.5 nA. Preliminary analysis indicates that a tor of l/\P(nT\. Hence a thick target is desirable statistical precision of ~2 X 10"7 in AT/2Twas achieved because sensitivity in the measurement of the helicity- in less than two shifts of data taking. This corresponds to dependent cross section is enhanced for a given sen a measurement in Aa/2a of better than 1 X 10-6. The sitivity in the raw measurement of transmission asym transmission of the H20 target used (T= 0.85) was of July-December 1981 PROGRESS AT LAMPF 13 Los Alamos National Laboratory similar magnitude to that expected from our liquid H2 developed by Bernstein, Brown, and Madsen.' This tech target presently under construction. A detailed analysis nique relies strictly on the electromagnetic properties of of the data, including systematic contributions, is the state, and on isospin invariance. Applications of this currently under way. approach to the results from hadronic probes have been very few. REFERENCES The mirror nuclei results determine only the magnitudes of MN and Mp, not their relative sign. This 1. M. Simonius, Phys. Lett. 41B, 415 (1972); and M. Simonius, Nucl. arises from taking the square root of the BE2 value in Phys. A220, 269 (1974). the derivation. In another language this lack of information about the 2. V. R. Brown, E. M. Henley, and F. R. Krejs, Phys. Rev. C9, 935 (1974). relative sign simply means that one cannot say whether the 2+ state of interest is isoscalar or isovector in charac 3. B. Desplanques, J. F. Danoghue, and B. R. Holstein, Ann. Phys. ter. 124, 449 (1980). In this experiment, now complete, we have measured + + + the relative signs for the first two 2 states (2, and 22 ) in 4. D. E. Nagle, J. D. Bowman, C. M. Hoffman, J. McKibben, R. E. 30Si, 34S, and 42Ca. The data were taken in the HRS Mischke, J. M. Potter, H. Frauenfelder, and L. Sorenson, High- channel at LAMPF during two runs in August and Energy Physics with Polarized Beams and Targets, AIP Conf. ' November totaling 120 h of polarized N-type beam at Pr'oc. No. 51, Ed., G. H. Thomas (American Institute of Physics, New York, 1978), p. 224. 500 and 800 MeV. Silicon-30 and -34 were selected because of recent shell-model calculations by Brown and 5. R. Balzer, R. Henneck, C. Jacquemart, J. Lang, M. Simonius, W. Wfldenthal* that indicated that the neutron and proton Haberli, C. Weddigen, W. Reichart, and S. Jaccard, Phys. Rev. contributions to'the cross sections for the 2,+ states in Lett. 44, 699-702 (1980). these nuclei have the same relative sign whereas for the + 34 22 state in S they have opposite sign. This low-lying 6. E. M. Henley and F. R. Krejs, Phys. P,ev. Dll, 605 (1975). isovector 2+ state in an s-d shell nucleus was a great sur prise to the theorises. It was suspected that the shell- 7. N. Lockyer, T. A. Romanowski, J. D. Biwman, C. M. Hoffman, model calculation was in error. The results of our R. E. Mischke, D. E. Nagle, J. M. Potter, R. L. Talaga, E. C. Swallow, D. M. Aide, D. R. Moffett, and J. Zyskind, Phys. Rev. measurement for this state confirm its isovector charac Lett 45, 1821-1824 (1980). ter, thus confirming the shell-model results. The isoscalar + 30 character of the 22 state in Si as predicted by the she'l model was also confirmed. The results for 42Ca are still Measurement of the Relative Sign of Neutron and under analysis and a shell-model calculation for this/- Proton Transition Matrix Elements in ip,p) Reac shell nucleus is expected soon. tions (Exp. 627, HRS) B. A. Brown and B. H. Wildenthal, private communication (to be published). (Los Alamos, Massachusetts Institute of Technology, Univ. of South Carolina) REFERENCE Spokesmen: M. V. Hynes (Los Alamos) and A. M. Bernstein (Massachusetts Institute of Technology) 1. A. M. Bernstein, V. R. Brown, and V. A. Madsen, Phys. Lett 71B, 48 (1977). The sensitivity of proton scattering to both proton and neutron densities offers the possibility of testing our understanding of the neutron structure of nuclei in a new way. In particular, s-d shell nuclei have been the subject A Test of the Interacting Boson Approximation of extensive shell-model calculations whose experimental (Experiment done at Bates Linac, Bates Exp. #782) tests have largely relied on proton densities derived from Spokesman: M. V. Hynes (Los Alamos) electron scattering. For T= 1 systems, a technique for deriving the magnitudes of the neutron (MN) and proton In addition to the ground state, the three low-lying and (M„) transition matrix elements for low-lying c+ states resolvable 2+ states in 1!6Gd allow for a test of the using the BE2 values from mirror nuclei has been interacting boson model of lachello and Arima. Our 14 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory results show that the model is inadequate to describe the This approach has had great success at lower energies data within the context of s- and rf-wave bosons. This (135 MeV).2 It is the main thrust of the current experi points to the importance of including higher order terms ment to test this approach at 500 MeV. The crucial dif in the model. ference between 135 and 500 MeV or higher energies is the rapid increase in inelasticity caused by, among other things, the opening of the pion channel. The central Electron Scattering from the Oxygen Isotopes theoretical question is whether or not the nuclear-matter (Experiment done at Bates Linac, Bates Exp. #756) formalism applied by use of the local-density approxima Spokesman: M. V. Hynes (Los Alamos) tion is indeed applicable at 400 MeV or whether one must resort to a field-theoretical description for the After several-thousand hours of beam time this experi medium corrections. ment has finally been concluded. The data represent a Data were taken in November using a 500-MeV N- complete study of the excited states of 160 up to 20 MeV, type beam on 160. Although results are still in the and of "O and I80 up to 10 MeV. This work has analysis stage, it appears that the importance of medium produced 4 Ph.D. theses and 12 journal articles. The im corrections is far less at 500 MeV than it was at lower portance of this study to nuclear structure arises from energies. The details of this result will become more ap the fact that 170 and l80 are perhaps the best parent when the asymmetry and other spin osbservables laboratories in which to test our understanding of the ad have been analyzed. dition of one or two neutrons to a double closed-shell The experiment is scheduled to run 240 h in June us nucleus. This experiment was also the starting point for ing L- and 5-type beam to complete the required the proton-scattering experiments at Indiana and measurements. The availability of the focal-plane LAMPF. polarimeter at HRS allows for a complete test of the nuclear-matter results because one can test predictions for spin observables other than asymmetries. The lower Structure of States in the Oxygen Isotopes via energy results were incomplete in this regard. Measurements of the Spin-Depolarization and Spin- Rotation Observables REFERENCES (Exp, 643, HRS) 1. F. A. Brieva and J. R. Rook, Nucl. Phys. A307, 493 (1978). (Los Alamos, Univ. of California at Los Angeles, Massachusetts Institute of Technology, Univ. of 2. J. Kelly etal., Phys. Rev. Lett. 45, 2012 (1980). Virginia, Lawrence Livermore Lab.) Spokesmen: M. V. Hynes (Los Alamos) and B. Aas (Univ. of California at Los Angeles) Measurement of the Triple-Scattering Parameters D,R,A, R', and A' for Proton-Proton and Proton- The importance of nuclear-medium corrections (such Neutron Scattering at 500 and 800 MeV as Pauli blocking) has recently been the topic of intense (Exp. 392, HRS) theoretical and experimental discussion. The possibility of constructing these medium corrections in a fundamen (Univ. of Texas at Austin, Rutgers Univ., Los Alamos) tal microscopic formalism without phenomenology has Spokesman: G. W. Hoffmann (Univ. of Texas at Austin) arisen from the theoretical work of Brieva and Rook1 and von Geramb. In their work the problem of an The small-momentum-transfer parts of the fundamen energetic proton in infinite nuclear matter has been tal nucleon-nucleon (N-N) amplitudes for p-p and p-n are solved. Using these results we have constructed a critical first-order ingredients for microscopic calcula density-dependent force or effective t matrix that can be tions that rely on the impulse approximation. Note also, applied to finite nuclei by use of the local-density approx if the free amplitudes are modified by the nuclear imation and in conjunction with the extensive electron- medium it is still necessary to determine the free am scattering data on 160. plitudes so that the modifications can be applied. For elastic scattering from a spin-zero target nucleus, only the spin-independent, a(q), and spin-orbit, c(q), am *H. V. von Geramb, private communication (to be published). plitudes are needed for the calculations. However, to July-December 19B1 PROGRESS AT LAMPF 15 Los Alamos National Laboratory determine a and c from N-N data, the other Wolfenstein these angles, the outgoing proton's transverse/vertical amplitudes (m, g, and h) must also be determined. In spin component precesses to a nearly longitudinal com the past, a determination of the a and c amplitudes ponent at the focal plane and cannot be determined. The directly from only N-N cross-section and analyzing- polarizations measured at the focal plane during the ex power data at 800 MeV led to three solutions. One of periment were separated into the appropriate polariza these solutions was basically equivalent to the phase-shift tion components at the target to determine the triple- solution obtained by Arndt using all the available data. scattering parameters. Thus, data other than cross-section and analyzing-power The second arm, the recoil-particle detection system, data apparently remove the three-solution ambiguity facilitated identification of quasi-free proton-proton and noted. However, there are very few 800-MeV data at proton-neutron scatterings from deuterium. By requiring small-momentum transfer (especially for p-ri) that con either a recoil neutron or a recoil proton in coincidence strain m, g, and h, so the a and c amplitudes determined with the HRS-detected event, it was possible to measure by phase-shift analysis may not be accurate at the level both the quasi-free proton-proton and proton-neutron required for microscopic analyses of 800-MeV p + triple-scattering parameters. The quasi-free p-p data, nucleus data aimed at determining nuclear structure in when compared with free p-p data to be taken in the next formation. phase of the experiment, will provide some indication of Thus, Exp. 392 was run to provide data that will help the validity of using quasi-free data to help determine the further constrain the small-momentum-transfer parts of free nucleon-nucleon scattering amplitudes at 800 MeV. the double-spin-flip amplitudes (m, g, and A), which in However, based on the results obtained in Exp. 385 turn implies additional constraints on a and c for the (p + n quasi-free analyzing powers), we expect the quasi- phase-shift analysis. free p-n results to correspond to the frd p-n case. Also, The first phase of this experiment was completed dur comparison of some of the quasi-free p-p data obtained ing runs in April and September 1981. The Wolfenstein in this experiment with free p-p data (Exp. 194) obtained triple-scattering parameters, D, A, R, A', and R' were at EPB shows remarkable agreement again suggesting measured for quasi-free proton-nucleon scattering at 800 that the quasi-free and free results are the same. MeV (using a LD2 target) for laboratory scattering Replay of the data taken during the April 1981 run is angles of 6, 10, 15, 20, and 25° (except for £>, which was complete and a final workup of the data is in progress. not measured at 20 or 25 °) using the HRS, the focal- Data obtained in September 1981 are now being re plane polarimeter (FPP), and a recoil-particle detection played. Preliminary results of the off-line analysis of the system. Six orientations of beam polarization were used data taken in April (6, 10, and 15° for proton-neutron, during the experiment: n(up/down), s(left/right), and and 10 and 15° for proton-proton) are shown in Figs. 1- l(parallel/antiparallel). The HRS detected the forward 10. The solid curves are the SF8 1 phase-shift predictions quasi-elastic high-energy protons while the recoil counter of Arndt. As is seen, good agreement is found for the detected, in coincidence with the HRS, the recoil proton proton-proton parameters, as expected, since existing or neutron. data have already partially determined the scattering am At the HRS focal plane the protons were rescattered plitudes. However, for proton-neutron parameters these by the FPP carbon analyzer to determine two of the out data represent the first measurements of this type at 800 going proton's spin components (transverse/horizontal MeV. Thus, the disagreement between experiment and and transverse/vertical). Because of precession of any phase-shift predictions is not surprising. spin component not parallel to the HRS magnetic fields, The discrepancies between the phase-shift predictions the spin components measured at the focal plane were and the experimental data (particularly for A' and R) for actually mixtures of the orthogonal set of spin compo the proton-neutron system indicate that these data, along nents at the target. It is for this reason that the Wolfen with the data taken in September 1981,should prove very stein triple-scattering parameter D could not be useful in constraining the scattering amplitudes at small- measured at 20 or ?'°i at the momenta corresponding to momentum transfer at 800 MeV. The September run ob tained data at 6, 20, and 25°, and the statistical errors associated with the D, A, R, A', and R' parameters ob By the 'Ann Arbor Convention," D = Dji/jy, R = Dgg, A = D^g, tained from that run for both p-p and p-n, for all angles, R' = DSL, A' = DLL. will be about ±0.015. 16 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory \.c i 1 1 1——r 1 1.0, —i 1 1 1 1 1 1- r——i— T 1 1 1 1 • (a) (a) 0.8 - (a) A, 792 MeV PROTON - NEUTRON 1.0 • - 0,8 0.6 """""•"'"•*-—«^* • I 0.8 - 0.6 • D, 792 MeV R, 792 MeV 0.4 PROTON - NEUTRON . ^r""* 0.6 0.4 PROTON - NEUTRON 1 1— i 1 1 i i... _i i i n •> i i/ i ii. i i 10 20 30 40 10 20 30 10 20 30 40 6c.in.Weg) 6c.m.Weg ) ec.mw«g) 0.4 —i 1 1 1 1 1 r- 1.0] (b) D, 792 MeV l.0| (b) R, 792 MeV 1 IIII. 0 • (a) R,' 792 MeV 0.8-- (a) PROTON - NEUTRON •^^ \ \ 0.2 V - 0.6- " 0.4 • Ns 0.4 A! 792 MeV <«- - PROTON-NEUTRON - ne -i i I i I i ,. i . . 10 20 30 40 0.2. 10 20 30 40 ec.m(deq ) Sc.m.Weg) i 1 0.2 - R; 792 MeV 1.0 (b) A,' 792 MeV PROTON-PROTON . PROTON-PROTON 0 0.8 T 0.2 ^y^ 0.6 • ' i i i . i 0.4, _i i i_ 10 20 30 40 10 20 30 40 6c.rn.toeg ) 6c,m.Weg ) Figs. 1-10. Results for D, R, A, R\ and A'for (a) p-n and (b) p-p at 800 MeV obtained during the April run. July-December 1981 PROGRESS AT LAMPF 17 Los Alamos National Laboratory Measurement of Spin-Flip Probabilities in Proton 1 1 1 1 1— Inelastic Scattering at 800 MeV and Search for 12C(p,p')12C, 1+, T = 1 (15.11 MeV) Collective Spin-Flip Modes (Preliminary Survey) Tp=397MeV (Exp. 411, HRS) (Los Alamos, Univ. of Minnesota, Rutgers Univ.) fc 10 Spokesmen: N. M. Hintz (Univ. of Minnesota) and J. M. Moss (Los Alamos) Experiment 411 has received beam time at 397 and 497 MeV to measure the spin-flip probability (SFP) in in elastic scattering. The 397-MeV data for l2C and 208Pb have been replayed and the data reduction is complete. The replay of the 497-MeV data is under way. The results obtained for the 1+, T=0 (12.71-MeV), 1\ T=l (15.11-MeV), and 2+, T= 1 (16.11-MeV) 0.2 - states in I2C are shown in Figs. l(a)-(c). The solid curves — • 1 1 1 l i 12 12 12, ..12 C(p,p') C, 2\ T = 1 (16.11 MeV) C(p,p') C,l+,T=0 (12.71 MeV) _ T =397MeV 1- Tp=397MeV 1.0 p - m 0.8 - < o_ » a. 0.6 -A I ' - _J II k 0.4 - a. in 0.2 (c) n l l i i l 10 15 20 25 10 15 20 25 0, Weg) cmm . Figs. l(a)-(c). Spin-flip probability for the transition to the (a) nC, 1+, 1 = 0 state at 12.71 MeV, (b) nC, 1+, T = 1 state at 15.11 MeV, and (c) i2C, 2+,T = l state at 16.11 MeV measured with an incident beam of 397-MeV protons. The solid curve is the calculation for this state done with the code DWBA-70 using the Cohen-Kurath wave functions and the Love-Franey effective interaction. 18 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory predict the shape of the data reasonably well, although whereas the neutron densities (three-parameter Fermi or they are slightly high for the forward angles. The calcula Gaussian distributions) were varied to obtain the best fits tions for the 15.11-MeV state reproduce the 4 and 6° to the cross-section data. data points exactly, but are too low at the larger angles. Unfortunately, the theoretical analyzing powers show The 16.11-MeV state calculations fall below the data at poor qualitative agreement with the data forward of 20°. all angles. As seen from Fig. 2, apart from reproducing the correct The discrepancies between these calculations and the (positive) overall sign of the envelopes, the curves fail to data may yield information on the nucleon-nucleon effec track the data. Particularly disturbing is the fact that tive interaction. At angles less than 3° the cross section very little structure in Ay is predicted forward of 20°, but for the isoscalar transition to the 12.71-MeV state is due the data continue to oscillate. Also, the minima in the mostly to a combination of the tensor and the spin-orbit theoretical cross sections (Fig. 1) are too deep. forces, with only a small contribution from the central Noteworthy is the fact that the neutron-proton rms spin-dependent force. The effect of the spin-orbit force radius differences are about 0.1 F smaller than values on the SFP can be seen in the fall off in SFP between 2 and 10° and after 18°. Although the 15.11-MeV-state cross section is dominated by the central force out to about 7°, the interference between the central and tensor 497.5-MeV forces can be seen in the difference between the p + NUCLEUS ELASTIC SCATTERING calculated 0° value of SFP = 0.58 and the pure central force value of SFP = 0.67, and also in the fall off of the predicted SFP between 0 and 7°. Further calculations are under way to test the sensitivity of the results to details of the wave functions and to the relative strengths of the various parts of the nucleon-nucleon effective in teraction. REFERENCE 1. W. G. Love and M. A. Franey, Phys. Rev. C24, 1073 (1981). ~p + Nucleus Elastic Scattering at 500 MeV (Exps. 425/433, HRS) (Univ. of "Texas at Austin, Northwestern Univ.) Spokesmen: G. W. Hoffmann (Univ. of Texas at Austin) and K. K. Seth (Northwestern Univ.) The data obtained in this experiment were presented in the last progress report. Here, we report the results of re cent theoretical analyses. The solid curves of Figs. 1 and 2 are results of Kerman-McManus-Thaler (KMT) calculations using proton-nucleon (p-N) amplitudes obtained recently by Fig. 1. Arndt (solution SL81) through phase-shift analysis of Elastic angular distributions for 500-MeV p + nucleon-nucleon (N-N) data. The proton densities were *°^Ca, 90Zr, and 20tPb, and results of KMT obtained from the empirically known charge densities, calculations (curves). July-December 1981 PROGRESS AT LAMPF 19 Los Alamos National Laboratory both energies, and the deduced neutron rms radii are too small; the discrepancies at 500 MeV are larger, however, than at 800 MeV. The sensitivity of the 500-MeV theoretical results to density uncertainties, to phase-shift amplitude errors, and to second-order correlation contributions was in vestigated, as already done at 800 MeV, and we con clude that such uncertainties cannot account for the ob served systematic discrepancies. The velocity-dependent, electromagnetic spin-orbit potential, which is significant for Ay for small q at 800 MeV, was included (not in cluded in Fig. 2) but does not account for the discrepan cies. Also, effects on the observables of the proper relativistic transformation of the nuclear N-N amplitudes from the N-N center-of-momentum (cm.) system to the Breit frame were found to be small. Finally, the impor tance of Fermi motion averaging was considered. Calculations at 500 MeV were carried out as above, ex cept that several N-N amplitudes corresponding to N-N laboratory energies varying between 325 and 800 MeV 2 2 Arnp = Harlree - Fock Fig. 2. Analyzing powers for 500-MeVp + *aMCa, wZr, and mPb, and results of KMT calculations as dis cussed in the text. obtained at 800 MeV, which are about 0.1 F smaller than that predicted by Hartree-Fock calculations (see 400 600 800 1000 Fig. 3). Thus, a consistent analysis leads to an apparent ENERGY(MeV) energy dependence for the deduced neutron distributions. We see similar problems with impulse-approximation Fig. 3. calculations at 500 and 800 MeV: the Ay predictions are Results obtained for the neutron-proton rms radius poor near q = 1.0-1.5 F_1 for each nucleus studied at differences for *°Ca and mPb at 500 and 800 MeV. 20 PROGRESS AT LAMPF July-Dec&mber 1981 Los Alamos National Laboratory l were used; the featureless structure in Ay near q = 1 F~ 3. Based on a series of calculations, we find that persisted, making it unlikely that the neglect of Fermi enhancement of Im{tso) between q = 0.4 and motion averaging is the cause of the discrepancies. 0.75 F-' improves the agreement between experi Thus, as a result of the sensitivity studies and because ment and theory for Ay, and suppression in this there is little reason to suspect the phase-shift analysis at region worsens the agreement considerably. 500 MeV, we are forced to consider the possibility that a Optimized results are shown by the dashed more fundamental theoretical inadequacy exists in the curves in Fig. 2. Note that the description of the conventional application of KMT. Because systematic data forward of 20° is qualitatively improved and and similar problems exist at 500 and 800 MeV, the clear that the reasonable impulse-approximation descrip implication is the same inadequacy at both energies. We tion beyond this angle is not disturbed. Similar believe an important clue to the origin of the difficulties is calculations at 800 MeV provide a much better fit 40 that theory fails to reproduce Ay at both energies over to the p + Ca Ay data obtained in Exp. 352 (see the same region of small-momentum transfer. Since any Fig. 4). Note that the KMT calculation that leads breakdown of the impulse approximation should be to Fig. 4 did not include the electromagnetic spin- momentum transfer dependent, we speculate that orbit potential. Based on the results seen in Fig. 4, momentum-transfer-dependent medium effects are pres we anticipate a quantitative fit to the 800-MeV data ent at 500-800 MeV that lead to a breakdown of the im when this effect is included in a calculation that ac pulse approximation at small q. counts for the medium effects. It is interesting to determine if effective amplitudes can The imaginary, effective spin-orbit amplitude for be found, through slight modification of the phase-shift p +p is shown in Fig. 5 (dashed curve) and lies well amplitudes at small q, that lead to better agreement with outside the error corridor of the free amplitude experiment. We have found the following phe- (shaded band) obtained from phase-shift analysis; nomenological results. the p + n comparison is similar. 1. Modifications to Re{t°) and Re(tso) do not 4. Finaliy, we note that a 10% (5%) suppression of significantly affect Ay or the neutron-proton rms Im{t°) at 500 MeV (800 MeV) and the spin-orbit radius differences Arnp. potential shown in Fig. 5 yields the expected Ar„_ 0 2. Increasing Im(t ) worsens the Ay prediction and for '"Ca as well as considerably improved descrip Ar„pgets smaller yet, whereas a 10% suppression of tions of the Ay data at both energies. Im{t°)eX small q improves Ayand increases Ar„p. Because little theoretical work has been done concern However, variation in Im(t°) alone cannot resolve ing effective interactions for energies greater than about the Ay and Ar^, discrepancies at 500 and 800 MeV. q(F') Q.g5 0.50 i.o -1 1 1 1 1 1 T" p + p 497.5 MeV ELASTIC 0.8 800 MeV * 0.20- -Medium modifieIUUIIICUd o*U Tc t CJV^ftj T I 1 ll 0.6 -Medium modi •V ' \\ 7 VV ' 0.2 Fig. 4. Fig. 5. so Results of KMT calculations for Ay for 800-MeVp The dashed curve is the effective Im(t ) used to + "'Ca (see text). generate Figs. 1, 2, and 4. July-December 1981 PROGRESS AT LAMPF 21 Los Alamos National Laboratory 200 MeV, it is not possible to compare our phe- Ay at forward angles for the 12.71-MeV state, should be nomenological results to theoretical expectations. We very useful in identifying unknown states. point out, however, that the Pauli blocking estimate of An example is the state at 18.27 MeV. The do/dCl and Clemente! and Villi suggests that lm[t°(0)] should be Ay shown in Figs. 1 and 2, respectively, are consistent reduced by about 10% (5%) at 500 (800) MeV, and that only with the unnatural-parity, T=0; a spin of 2" is an extrapolation of a comparison of impulse- likely from the position of the peak in the angular dis approximation and medium-modified spin-orbit optical tribution. The complex at 19 MeV has been studied potentials between 100 and 200 MeV hints that the carefully, and states have been clearly identified at 19.28, so medium-modified Im(t ) amplitude at higher energies is 19.40, and 20.6 MeV. Overlapping states at 19.58 and so larger than the impulse approximation Im(t ). 19.74 MeV have been tentatively identified for values of We conclude that a proper explanation of both the q larger than about 1.2 F-1. 500- and 800-MeV data demands an accurate, quan The 1" (T= 0) state at 10.84 MeV is also interesting. titative accounting of nuclear-medium corrections to the The cross-section angular distribution is strikingly impulse approximation. Such findings are also consistent similar to that for the 9.65-MeV 3~ state, even at the with results obtained recently in a KMT analysis of 400- 208 smallest values of q measured. Distinguishing between MeV proton scattering from Pb. ( = 1 and (= 3 giant resonances by such small-? cross- section measurements in (p.p1) thus looks impossible; The 12C {p,pf2C Reaction at 400, 600, and 700 MeV l2C(j?.p')12 C E„= 18.27 MeV (Exps. 432/531, HRS) (Rutgers Univ., Los Alamos, Univ. of Minnesota, CEN •••• • Saclay, Univ. of Texas at Austin, Univ. of California at Los Angeles, Univ. of Pittsburgh) • Spokesmen: C. Glashausser (Rutgers Univ.) and J. Moss l_ * E =400MeV (Los Alamos) p 4 Differential cross sections and analyzing powers for the "Cjp.pQ^C reaction have been measured for inci ** f ' ••• -o - t dent proton energies of 400, 600, and 700 MeV. Results • • were obtained for states up to an excitation energy of 1 about 21 MeV and over a momentum transfer range of Ep»600MeV 0.3-2.1 F_1. Preliminary results for the 12.71-MeV, 1+, T = 0 and 15.11-MeV, 1+, T= 1 states and the lack of i evidence for pion precursors have been reported 1 t previously. V t Optical-model calculations for simultaneous fits to the elastic cross-section and analyzing-power data are being _ £p*700MeV performed. Preliminary results indicate that a reasonable f overall fit at 400 MeV may be obtained by increasing the real spin-orbit potential radius by about 20% and the im aginary spin-orbit potential strength by a factor of 2 over f values used in previous calculations where analyzing- power data were not available.2 1 1 Data analysis is almost complete for all states. In ad dition to the well-known natural-parity collective states, q(F~') the spectrum is rich in unnatural-parity states of different Spins with both T=0 and T= 1. The energy indepen Fig. 1. dence of the absolute cross sections noted for the 12.71- Differential cross section for 18.27-MeV (J71, and 15.11-MeV states, together with the negative sign of T = 2",0) state at Ep = 400, 600, and 700 MeV. 22 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory I2«,- ,2 C(p,p') C Ex= 18.27 MeV Excitation of the Giant Resonance Continuum with 0.6 Intermediate-Energy Protons E = 400MeV 0.4 p (Exp. 473, HRS) (Los Alamos, Massachusetts Institute of Technology, 0.2 I • l.O Univ. of Minnesota) Ay 0 2.0 Spokesmen: G. Adams (Massachusetts Institute of -0.2 + • • q(F~') Technology) and T. Carey and J. Moss (Los Alamos) -0.4 _1 -0.6 At small-momentum transfers (q < 3 F ), inelastic scattering with energy loss of 5-50 MeV leads to the ex citation of broad giant resonances (GRs) and a nearly 0.6 - featureless continuum on which the GRs lie. Since for E =600MeV 0.4 p hadron scattering the continuum cross section is typically 5-10 times that contained in GRs, it is ob 0.2 0 viously of great interest to try to understand its excita Ay o l0 * " • , tion, if only to better understand the characteristics of 1.0 2.0 -o - GRs. -0.2 q(F'<) 1- 1 <> In this report we first show that the cross section for -0.4 the low-excitation-energy continuum excited by 800- -0.6 -o - MeV protons may be understood in terms of a single- collision model based on Glauber theory.' A significant feature of the calculation, which is also seen in the data, 0.6 - is a decrease in the continuum cross section at small E =700MeV 0.4 p angles because of Pauli blocking. Then, looking at con 0.2 •Q - tinuum analyzing powers and spin-flip probabilities, we •Q - 0 present evidence that spin-dependent strength is greatly Ay o * 1.0 2.0 suppressed in the low-excitation-energy region of the -0.2 nuclear continuum. -0.4 A typical GR-plus-continuum spectrum for 800-MeV * protons on 116Sn is shown in Fig. 1, together with -0.6 : * Fig. 2. l,6Sn(p,p')"6Sn Analyzing power for 18.27-MeV (Jn, T = :2",0) Ep = 800 MeV state at Ep = 400, 600, and 700 MeV. there are small differences, however, in Ay. Analysis of all these states with the new DWBA-81 code is just begin ning. REFERENCES 1. C. Glashausser etal., Los Alamos National Laboratory Group MP-10 Progress Report (January-June 1981), p. 77. 2. J. L. Escudie etal., Phys. Rev. Rapid Commun. 24, 792 (1981). Fig.l. Spectrum of 116Sn compared with calculations us ing the FG and SIS approximations. July-December 1981 PROGRESS AT LAMPF 23 Los Alamos National Laboratory 10 I 1 I 1 theoretical curves, which are discussed below. One sees - 6 ,,6 - the giant quadrupole-monopole resonance doublet near FG " Sn(p,p') Sn Ex — 14 MeV and the high-energy octupole resonance - f\L Ep = 800MeV - near Ex = 23 MeV. We have chosen the region near Ex - J>$\V E- = 30MeV - = 30 MeV, which appears free of any obvious GRs, for 3 -SIS/ . evaluation of the angular distribution of the continuum sfc. in _ shown in Fig. 2. A most interesting feature of the angular v. J3 distribution is an obvious decrease in cross section at £ small scattering angles. This is, to our knowledge, the uJ - •a first evidence of such behavior. In GR studies with 100- a•a to 200-MeV alpha particles (the bulk of all GR work), an *>b> exponential increase in continuum cross sections with CM •o I decreasing scattering angle has always been observed.2 - It is plausible to assume, for the scattering of intermediate-energy protons with small energy loss and - small-momentum transfer, that single collisions r\R I I i I 10 15 20 25 dominate. In this spirit Bertsch and Scholten3 have 0L(deg) developed a model for continuum excitations based on Glauber theory.1 The differential cross section is ex Fig. 2. pressed as Angular distribution of the continuum cross section at Ex = 30 MeV compared with calculations using the FG and SIS approximations. d2a ' da\ Nt„S(q,E) dQ.dE M nuclear surface more realistically. The curve labeled FG in Fig. 1 (and in Fig. 2) shows that the FG model is not where {drs/dil) is the differential cross section for free NN able to account for the shape of the continuum spectrum. nucleon (N-N) scattering and S(q,E) is the nuclear It does, however, yield the qualitative features of the response function. The effective number of target angular distribution — in particular, the decrease in nucleons participating in the single-collision cross-section cross section at small angles. This decrease is due to the Ntf is determined as fact that the recoil nucleon does not have sufficient momentum to rise above the Fermi surface; it is thus Pauli blocked. / db2 x(&)e~x(A) N The main defect of the FG model seems to be an el _T overestimate of the Pauli blocking at small q. The SIS calculation, which will be described in detail elsewhere,3 remedies this defect by giving the nucleus a surface where region where the effects of Pauli blocking are partially suppressed. It is clear that a proper treatment of the sur face is necessary for a realistic model of S{q,E) because, Tib) dz p C£N in 1ISSn, most of the contribution to N^ comes from a -ooJ region of the nucleus where the density is less than one- quarter that of nuclear matter. The curves labeled SIS in Figs. I and 2 show that the spectral shape and angular Taking qJN = 40 mb, we find NtB = 7.6 for scattering distribution are now very well reproduced. from n6Sn at 800 MeV. The evidence strongly suggests the dominance of The response function is evaluated using the Fermi- single-step quasi-free scattering. On this basis, one would gas (FG) model and the semi-infinite slab (SIS) approx also expect the polarization observables for the con imation, which treats the effects of Pauli blocking in the tinuum to be similar to the free N-N values. Figure 3(a) 24 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory i (0) which As = 0 dominates result in SFPs near zero. Thus, 0.4 the small SFP seen here implies a deficiency of As = 1 -n-p" ^ over As = 0 scattering with respect to the free N-N case. §0.2 £. ll6 ll6 >> r Sn(p,p') Sn Nuclear collectivity associated with long-range fields is < known to be mostly spin independent, with the result that 0 Ep=800MeV the low-excitation-energy spectra of nuclei abound with -0.2 > i i scalar collective excitations (including GRs). Less is known about spin collectivity, but present evidence 8O8H>{p,p')80BPb suggests that it is not nearly as strong as the spin- Ep=400MeV 6 7 P-P independent variety. ' Qualitatively, at least, the SFP AVERAGE data are in accord with this observation. REFERENCES n-p 1. R. J. Glauber, in Lectures in Theoretical Physics, Ed., W. E. Grit- tin etal. (Interscience, New York, 1959), Vol. 1, p. 315. 2. D. H. Youngblood etal., Phys. Rev. C13, 994 (1976). P-P 3. G. F. Bertsch and O. Scholten, to be published. n-p 4. R. Arndt, "Scattering Analyses Interactive Dial-in," Virginia Polytechnic Institute and State University report. 5. W. D. Cornelius etal., Phys. Rev. C23, 1364 (1981). Figs. 3(a)-(c). (a) Analyzing power of the continuum at the energy 6. G. Bertsch, Nucl. Phys. A354, 157 (1981). of the quasi-elastic peak, (b) spin-flip probability 20S 7. N. Anantaraman etal., Phys. Rev. Lett. 46, 1318 (1981). for the continuum for Ex = 7-22 MeV in Pb, and (c) spin-flip probability for the continuum for Ex = 12-29 MeV in 90Zr. Proton Scattering from 20Ne at 0.8 GeV (Exp. 475, HRS) shows that this expectation is confirmed in the case of (Univ. of South Carolina, Univ. of Texas, Univ. of Min the analyzing power for the U6Sn(/>,/?')116Sn reaction at nesota, Michigan State Univ.) 800 MeV.4 Very similar results are found for less exten Spokesman: G. S. Blanpied (Univ. of South Carolina) sive data on 90Zr with 500-MeV protons and for 208Pb at 400 MeV [Figs. 3(b) and (c)]. In several recent publications, coupled-channels In sharp contrast to this simplicity, the spin-flip analyses of ~l-GeV proton inelastic scattering from probabilities (SFPs on figures and equations) for the con- light, s-d shell nuclei and heavy rare-earth nuclei have 20B tinua in Pb (7-22-MeV excitation energy at Ep = 400 been shown to be generally successful, provided defor W 1 6 MeV) and ZT (12-29-MeV excitation energy at Ep = mation and multistep processes are properly treated. " 500 MeV) are consistent with zero, whereas the N- and These calculations, which assume the collective Z-weighted values from the phase-shift solutions4 are rotational model, provide excellent descriptions of the near 0.2 and 0.1, respectively. data for the lowest 0+, 2+, and 4+ states in M,26Mg We believe that the large difference between the free (Ref. 6). N-N and continuum SFPs is due, at least in part, to the The multipole moments of the empirically determined difference between the scalar and vector (spin-dependent) optical potentials, which are related to those of the response functions. It has been shown5 that inelastic deformed-matter densities by Satchler's theorem,7 can be proton scattering with spin transfer (As = 1) invariably compared with the multipole moments of the charge den leads to a large SFP (5>0.5), whereas reactions in sities obtained by electromagnetic measurements. In July-December 1981 PROGRESS AT LAMPF 25 Los Alamos National Laboratory T—j i i i i i i t )—n—n—i i i—r~i—i i i i—i—n—r general, the deduced M{E2, matter) moments are 10- 20% smaller than those of the charge densities for 12C, !0Ne(p,p'), 0.8 GeV + + + MMg, and J6Mg (Refs. 2 and 6). — 0 ®2 ®4 In these calculations the radius parameter of the op — 0+®2+, 04 = 0 tical potential is deformed by — DWBA /{(6)=/«(i(i+p2y20+p4y40+....) . (1) 12 24 The results for C and Mg indicate that p4 ~ 0, so that 26 the hexadecapole moment is small, whereas p4 for Mg is somewhat larger, Results from low-energy hadron 20 scattering suggest that p4 in Ne is large (P4/p2 ~ 0.5) (Refs. 8-15). To further the study of intermediate-energy proton inelastic scattering from light, deformed nuclei, data for 20Ue(p,p') at 0.8 GeV were taken with the High- Resolution Spectrometer (HRS). Since this was the first experiment at the HRS to use a gas target, some details are given here. The experiment consisted of scattering 0.8-GeV protons from a 20Ne gas target, enriched to 99.95%. The measured angular dis tributions extend from 5.3-26.3° cm. for all states up to about 12 MeV. The {p.p") data presented here are for the excitation of the (ground, 0+), (1.634-MeV, 2+), (4.247- MeV, 4"), and (8.7-MeV, r and 6+) states in 20Ne. Data were also acquired for a UN gas target of iden tical geometry and a 208Pb foil. The ratios of the 14N gas- target data to previous 14N measurements that used a 16 solid melamine target provide a value of the beam- D 15 20 25 30 interaction volume in the gas target as a function of scat ©c.m.(deg) tering angle. The interaction volume is found to be con stant to 6.8°|,b, where it falls off as 1/sin 9,,b. A least- Fig. 1. 14 squares fit to the ratio of gas/solid for N was used to Angular distributions of 20Ne(p,p') at 0.8 GeV for 20 compute the absolute normalization of the Ne data the 0+, 2+, 4+, and unresolved doublet (1~ + 6+) presented here, with an overall uncertainty of about are shown. The curves result from coupled- 10%. The absolute scattering angle was determined to channels and DWBA calculations as discussed in 20, ±0.05 ° by comparing the Pb data taken here with that the text. of Ref. 17. The resulting angular distributions for the 0+, 2+, 4+, and unresolved (1 ~ to 6+) states are presented in Fig. 1. The Woods-Saxon potential parameters for the Coupled-channels calculations using a deformed op coupled-channels calculations, given in the low-energy + + + tical potential have been made in which the 0 , 2 , 4 , notation {V, W, r, a, rw, aw, and rc) are (—5.0 and +48.0 and 6+ states in the ground-state rotational band (GSRB) MeV, 1.06, 0.46, 1.06, 0.46, and 1.05 F). The solid + + are coupled with deformation up to p6. The results for curves shown in Fig. 1 result from coupling the 0 , 2 , + + various values of the parameters are given in Fig. 1. 4 , and 6 states with parameters p2 = +0.46, p4 = Distorted-wave-Bom-approximation (DWBA) calcula +0.27, and p6 = +0.03; the long-dashed curves are the + + tions using a spherically symmetric optical potential are result of coupling only the 0 and 2 with p2 = +0.57 also shown for comparison with the coupled-channels and p4 = p6 = 0. The short-dashed curves are from results. DWBA calculations. The optical-potential parameters 26 PflOQREStATLAMPF July-December 1981 Lot Alamos National Laboratory 22 for the DWBA calculations are {V, W. r, a, rw, aw, and calculations. Thus, the ratio of the M(E2) from 0.8 rc) = (-7.6 and 45.1 MeV, 1.03,0.571, 1.03,0.571, and GeV to that extracted in electromagnetic measurements + + 12 2, 1.05 F), with p2 = 0.63 for the 2 , p4 = 0.50 for the 4 , for the N = Z nuclei C and Mg is about 0.9, whereas + 20 and p6 = 0.16 for the 6 states. the value determined here for Ne agrees with the Both the relatively large cross section for the 4+ state average of the electromagnetic values19 but is about 0.9 and the position of the first minimum in the angular dis in individual cases.20,21 tribution for the 2+ state provide evidence for a large Calculations are planned that will facilitate the direct hexadecapole deformation for the 20Ne ground state. comparison of the data with transition matrix elements Since the 6+ state is unresolved from a nearby 1" state, it predicted from shell-model results using the Chung- 19 is difficult to make a quantitative evaluation of the p6 Wildenthal interaction. deformation. The angular distribution for excitation of the 1~ state should be very forward peaked and should REFERENCES fall off faster than that for the 6+ state. A coupled- channels calculation with p2 = +0.46, p4 = +0.25, and 1. L. Ray, G. S. Blanpied, W. R. Coker, R. P. Liljestrand, and G. + P6 = +0.07 is given by the dot-dashed curve for the 6 W. Hoffmann, Phys. Rev. Lett. 40, 1547 (1978). state. The two coupled-channels curves for the 6+ state thus represent a reasonable range of possible strength of 2. G. S. Blanpied etal., Phys. Rev. C23, 2599 (1981). this angular distribution. 3. G. S. Blanpied etal., Phys. Rev. C20, 1490 (1979). As has been done previously for 12C, 24Mg, and 26Mg (Refs. 2 and 6), multipoles of the deformed optical poten 4. L. Ray, G. S. Blanpied, and W. R. Coker, Phys. Rev. C20, 1236 tials can be related to those of the matter distributions by (1979). Satchler's theorem.7 The moments that result from the solid curves p2, p4, p6 = 0.46, 0.27, 0.03 are M(E2) = 5. M. L. Barlett etal., Phys. Rev. C22, 1168 (1980). 0.168 eb, M(E4) = 0.0244 eb2, and M(E6) = 0.0033 eb3, whereas the values for p2, p4, p6 = 0.46, 0.25, 0.07 are 6. G. S. Blanpied et al., submitted to Phys. Rev. C. 0.0168 eb, 0.0248 eb2, and 0.0038 eb3. M(E2) = 0.163 + + for only 0 ,2 coupling, p2 = 0.57, and p4 = p6 = 0. 7. G. R. Satchler, J. Math. Phys. 13, 1118 (1979). Thus, the magnitude of the 2+ state determines the M{E2) moment, and the uncertainty of the strength of 8. R. de Swiniarski etal., Phys. Rev. Lett. 23, 317 (1969). the 6+ has little effect on the determined moments. As seen by the long-dashed curves in Fig. 1, the 0+,2+ coupl 9. R. de Swiniarski etal., Phys. Rev. Lett. 28, 1139 (1972). ing with only p predicts an angular distribution that 2 10. R. de Swiniarski etal., Phys. Lett. 43B, 27 (1973). misses the first minimum in the 2+ state by about 1°, whereas the full coupling with a large hexadecupole 11. R. C: Swiniarski etal., J. Phys. (Paris) 35, L-25 (1974). deformation predicts an angular distribution that is in phase with the data. The DWBA calculations also are 12. R. S. Mackintosh and R. de Swiniarski, Phys. Lett. 57B, 139 not in phase with the 2+, 4+, and 6+ data. The remaining (1975). differences between the full coupling prediction and the data can be attributed to the restrictive shape for the 13. H. Rebel etal., Nucl. Phys. AI82, 145 (1972). potential or to the use of the same p2 coupling between the 0+ and 2+, the 2+ and 4+, and the 4+ and 6+. There is 14. H. Rebel and G. W. Schweimer, Z. Phys. 262, 59 (1973). evidence that the coupling changes as one goes up to the rotational band in light, deformed nuclei.18 15. R. S. Mackintosh, Z. Phys. A276, 25 (1976). The M(E2) moment determined here is 0.168 eb, com 16. G. S. Blanpied, M. L. Barlett, G. W. Hoffmann, and J. A. pared to the B{E1) value of 0.171 ± 0.011 eb from the McGill, submitted to Phys. Rev. C. average of electromagnetic studies19 [with some measurements as high as 0.179-0.183 (Refs. 20 and 21)], 17. G. W. Hoffmann etal., Phys. Rev. C21, 1488 (1980). 0.150 eb from shell-model results using effective 18. A. Bohr and B. R. Mottelson, Nuclear Structure, Vol. II (W. A. charges,19 and 0.159 eb from Hartree-Fock Benjamin, Inc., Reading, Massachusetts, 1975), p. 96. July-December 1981 PROGRESS AT LAMRF 27 Los Alamos National Laboratory 19. B. H. Wildenthal, "Elementary Modes of Excitation in Nuclei," The recent report of 8+ and 10+ levels of the MSi Eds., A. Bohr and R. A. Broglia (North Holland Publishing Co., GRSB5 has further supported a collective description of Amsterdam, 1977), p. 383; and W. Chung, ihesis, Michigan this nucleus and has stimulated efforts to find high-spin State University, 1976 (unpublished), levels in ^Mg. From Exp. 476 we have evidence for a 6+ state in 26Mg at 8.03 MeV. The evidence arises from data 20. D. Schwalm, E. K. Warburton, and J. W. OIness, Nucl. Phys. A293, 425 (1977). taken in an experiment to determine analyzing powers and differential cross sections for 0.8-GeV polarized- 21. Y. Horikawa, Y. Torizuka, A.. Nakada, S. Mitsunobu, Y. Ko- proU n inelastic scattering from levels in "Mg. The ex jima, and M. Kimura, Phys. Lett. 36B, 9 (1971). periment was performed using the HRS. Though the level at 8.03 MeV has been observed previously,3 the 22. Y. Abgrall, B. Morand, and E. Caurier, Nucl. Phys. A192, 372 limited data obtained in the past have been insufficient to (1972). permit any spin assignment. The angular distribution measured in this experiment for protons exciting the 8.03-MeV level is shown twice in Polarized Proton Scattering from 24,26Mg at 0.8 Fig. 1. The theoretical curves shown are discussed below. GeV The following observations yield support for the 6+ (Exp. 476, HRS) assignment for the 8.03-MeV level. (Univ. of South Carolina, Univ. of Texas, Rutgers Univ.) 1. The position of the first maximum in the angular Spokesman: G. S. Blanpied (Univ. of South Carolina) distribution with respect to other states of known spin in 26Mg implies a transferred angular momen Rotational band structure has been recognized as a tum >4, indicating the excitation of a state with systematic feature in the spectra of light nuclei with J > 4. Whereas the distribution of Fig. 1 peaks at 20 < A < 28 with partially filled s-d shell levels, and has about 13°, the 4+ levels peak at ~11°, with all been suggested for 20Ne, 22Ne, 24Mg, and 28Si. In addition other levels of known spin peaking at smaller to the resemblance of the observed series of levels to es angles. tablished features of collective rotational bands, such 2. Coupled-channels calculations for a 6+ level in a proposals have been supported quite well by collective- GSRB in 26Mg reproduce reasonably well the ob model coupled-channels calculations in several cases.1,2 served angular distribution for the 8.03-MeV level. These calculations reproduce most of the measured The results of these calculations, made using the angular distributions of proton excitations of these levels, code JUPTER6 with the same parameters as the giving strong support for the assignment of these levels solid curves of Fig. 9 in Ref. 3, are shown in the to collective rotational bands. lower portion of Fig. 1. As is seen in the figure the A good example3 is the level scheme of MMg. The angular distribution observed is well described by states in 24Mg can be grouped into a ground-state these calculations, though perfect agreement has rotational band (GSRB) consisting of the (0.00-MeV, not been achieved. The values of p6 shown would 0+), (1.37-MeV, 2+), (4.12-MeV, 4+), and (8.12-MeV, 6+) indicate that the 64-pole deformation is quite small K + + levels. Additionally, there is evidence for K = 2 , 0 ,0~, (p6 = -0.02 ± 0.01). The magnitude of the dif and 3" bands. In fact, nearly all levels below 10 MeV in ferential cross section is well predicted except for MMg are believed to belong to a rotational band. Aside the angle farthest away from the maximum where from 24Mg, levels in 20Ne, 22Ne, and 28Si have been other channels of the reaction process may con assigned to a GSRB, and the 6+ member of the GSRBs tribute. These calculations may be improved by us 4 in each of these nuclei has been observed. The extension ing a varying rather than a fixed (32> but this of these ideas to 26Mg would seem to be straightforward, modification to the computer code has not been particularly since the features of the 24Mg-level scheme made. Also, the present version of JUPTER does not show strong evidence of collective behavior. However, include a Yso term in the Hamiltonian, thus not no level with spin >4 has been reported previously. allowing coupled-channel calculations for a 5~ n _ _ _ 24 Hence, a collective description of 2sMg has been based level. In the K = 0", (1 , 3 , 5 ) band of Mg, it on a series of rather limited bands, with some evidence of was noted that coupled-channels calculations for band mixing.3 the 5~ level, which did not include such a direct step from the ground state, were an order of 28 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory may be obtained by such a spherical potential and 26 Mg(p,p'),0.8 GeV no coupling. 10° 803-MeV statr' 4. Comparison with known 6+ levels in 24Mg can suggest, by arguments based on systematics, that 10-1 the level at 8.03 MeV may be a 6+. In 24Mg, a 6+ level is observed at 8.12 MeV, which is very nearly 10-* the same in energy as the 8.03 MeV observed for the level under discussion, though the angular dis £io-3 tributions are not similar. Another level at 9.53 C MeV in 24Mg has been identified as a 6+ level,3 •S io° however, and its shape (peaking at about 14°) and its magnitude at maximum (0.28 mb) bear a strong M io- resemblance to the 8.03-MeV level in Mg. The lack of resemblance between the 8.12-MeV level in 24 io-z Mg and the 8.03-MeV level in "Mg probably results from the difference in interference between direct and multistep excitation for those levels. 10- 5. Agreement with rotor and shell-model predictions & -0.02 of energy of excitation also suggests that the ob io-* A -003 + served level at 8.03 MeV may be a 6 level. Com parison with rigid-rotor calculations for neighbor _L _L. 5 10 15 20 25 30 ing nuclei suggests that such a model may be a ©cmWeg) useful tool in predicting GSRB energies, though the energies.predicted are usually higher than those ob Fig.l. served, as shown in Table I. Basing the moment of Comparison of measured angular distribution for inertia for 26Mg on the 4+ -*• 2+ energy difference 26 8.03-MeV level in Mg with DWBA (upperpor yields a prediction of 8.29 MeV for a GSRB 6+ in tion) and coupled-channels (lower portion) calcula 26Mg, adding support to the assignment of ( = 6 for tions. the 8.03-MeV level. Predictions for the 6+ in several s-d shell nuclei compared to the measured value are also given for comparison. magnitude too low in predicting the observed angular distribution.3 Distorted-wave-Born-approximation (DWBA) TABLE I calculations for a (=5 angular distribution reproduce the observed phenomena quite well. The EXCITATION ENERGY (IN MeV) OF THE results of these calculations are also shown in FIRST 6+ STATES IN SEVERAL DEFORMED Fig. 1, where the potential used is that of Ref. 3. s-d SHELL NUCLEI (ROTOR CALCULATIONS + + Here, values of p5 = 0.14 and p6 = 0.07 were used. BASED ON 4 ->• 2 TRANSITION ENERGY) A general feature of high-spin DWBA calculations performed on nuclei in this region is that the 20Ne 2Ne 4Mg "Si 16Mg angular distributions predicted by the calculations peak at larger angles than observed. Hence, these calculations support an assignment of J > 5 Observed 8.78 6.31 8.11 8.54 (8.03)* because, as seen in the figure, the ( = 5 distribution Rotor 8.36 6.63 8.45 9.08 8.29 b matches the peak quite well whereas the ( = 6 CW 8.54 6.26 8.47 9.06 8.73 curve is seen to peak at a larger angle than measured. Though the validity of applying DWBA aProposed here as 6+. calculations to deformed nuclei is questionable, it is "CW denotes shell-model calculations using Chung-WUdenthal in interesting to note that a satisfactory fit to the data teraction (see Ref. 7). July-December 1981 PROGRESS AT LAMPF 29 Los Alamos National Laboratory Shell-model calculations using the Chung- region. These have been interpreted as dibaryon 3 1 WildcnthaJ interactions have been performed for "resonances" in the *D2 and F3 channels. Detailed several s-d she!! nuclei.*'7 These calculations, which phase-shift analyses of these data reveal that these are also given in Table I, again usually predict resonances are largely inelastic. Because the only in higher energies for the members of the GSRB than elastic channel of any importance that is open at these are observed (except for 20Ne). These calculations energies is that for single-pion production, it is obvious predict a 6+ level at 8.73 MeV, which may be that the strongest signals of these resonances should ap regarded as an upper limit on the energy of such a pear in this channel. Further, because polarization state. The 8.03-MeV state would then be a variables are sensitive to interference between different possibility for that 6+ level. partial waves, it may be expected that their measurement Theoretical analyses of the other data from this experi and analysis as a function of incident energy will provide ment are in progress. very discriminating evidence for the existence (or nonex istence) of these resonances. This point of view has B. H. Wiidenthal (private communication). motivated us to start precision studies of the cross sec tion (a) and analyzing power (Ayo) of the reaction REFERENCES 1. G. S. Blanpied, N. M. Hintz, G. S. Kyle, J. W. Palm, R. Lil- p + p -* d + n+ jestrand, M. Barlett, C. Harvey, G. W. Hoffmann, L. Ray, and D. G. Madland, Phys. Rev. C20, 1490 (1979). in the energy range 550-800 MeV in 50-MeV steps. 2. G. S. Blanpied, G. A. Balchin, G. E. Langston, B. G. Ritchie, M. L. Barlett, G. W. Hoffmann, J. A. McGill, M. A. Franey, M. Gaz- Data so far have been taken at 547, 597, 647, 697, zaly, and B. H. Wildenthal, submitted to Phys. Rev. C. and (as a part of our Exps. 10/233) at 792 MeV; that is, only a gap at 750 MeV remains. Recoil deuterons, in 3. G. S. Blanpied, N. M. Hintz, G. S. Kyle, M. A. Franey, S. J. their narrow recoil cone (generally <18°), were detected Seestrom-Morris, R. K. Owen, J. W. Palm, D. Dehnhard, M. L. to obtain data at extremely forward and backward pion- Barlett, C. J. Harvey, G. W. Hoffmann, J. A. McGill, R. P. Lil- production angles. Pions were detected to cover the jestrand, and L. Ray, to be published in Phys. Rev. C. remaining angular range. The total angular range covered was 4° < 6c.m.(jr) < 168°. Solid targets (CH2) 4. P. M. Endt and C. Van der Leun, Nucl. Phys. A3I0, 1 (1978). were used for the first part of the data at 547 and 647 MeV. A liquid-hydrogen target was used for all subse 5. S, Kubono, M. H. Tanaka, S. Kato, M. Yasue, M. Sekiguchi, K. Kamitsubo, and T. Tachikawa, Phys. Lett. 103B, 320 (1981). quent energies. Preliminary results for the analyzing power at 457, 647, and 792 MeV are shown in Figs. 1-3. 6. T. Tamura, Rev. Mod. Phys. 37,679 (1965); and T. Tamura, Oak These have been analyzed to give coefficients of the Ridge National Laboratory report ORNL-4152 (1967), un orthogonal polynomials, published. 7. B. H. Wildemhai, "Elementary Modes of Excitation in Nuclei," 4 a Eds., A. Bohr and R. A. Broglia (North-Holland, Amsterdam, * °oo = £ nPn (cos 6) 1977), p. 383; and W. Chung, thesis, Michigan State University n even (1976), unpublished. and Precision Studies of ~p + p —*• d + n+ as Probe of cos e Dibaryon Resonances 4™fo = £ bipN ( ) > n (Exp. 508, HRS) (Northwestern Univ.) where Spokesman: K. K. Seth (Northwestern Univ.) Pronounced structures in p-p total cross sections Ao L ° = °O0 + PB * " °yo and AcT have been reported in the Ep = 500-800-MeV 30 WI0QBE88ATLAMPF Juiy-Decembar 1981 Los Alamos National Laboratory ~i 1 1 r The data for 597 and 697 MeV are still being analyzed. p(p,n+)d Preliminary results indicate that all coefficients of c^ (a0, a2, aA, and a6) and the even coefficients of ayo (b0,62» Ep=547 MeV and b4) all show resonant behavior at ~600 MeV, as they should, because of their direct coupling to the NA chan J nel through the D2 channel of the initial p-p system. BLANKLEIDER However, what is quite surprising is that coefficients b^ J"; and b} of ayo, which do not couple directly with the even partial waves of the initial p-p system, show very strong resonant behavior at —675 MeV. This is not predicted by any of the calculations available to us so far, including the well known work of Niskanen2 and the new and much more ambitious analysis of Blankleider and 3 0 20 40 60 80 100 120 140 160 ISO Afnan. Do the data reqr.ire introduction of a resonance de 3 »cm< 9> in the F3 channel? Excited ai we are about our results we cannot go that far, at least not yrt! Fig.L + Analyzing power for the p(p,n )d reaction at Ep = 547 MeV. REFERENCES 1. R. Bhandari, R. A. Aradt, L. D. Roper, and B.J. VerWest, Phys. and Rev. Lett. 46, 1111 (1981). 2. !. A. Niskanen, Phys. Lett. 79B, 190 (1978), and 82B, 187 (1979). 1 of — o\ _ _'yoa •*-yo 3. B. Blankleider and I.R. Afnan, Phys. Rev. C24, 1572 (1981). 0.8 1 1 r-" • i i P(pV)d 0.7 " E =647MeV p BLANKLEIDER vBLANKLEIDER 0.6 0.5 . NISKANEN, , -\ ji ±/jL. «04 < i Tit* vv 0.3 0.2 • / W " OJ i i - I t III' •"O 20 40 60 80 100 120 140 160 180 20 40 60 80 100 120 140 160 180 de Wde9> W «> Fig. 2. Fig. J. + + Analyzing power for the p(p,Jt )d reaction at E„ = Analyzing power for the p(p,ir )d read ion at Ep = 647 MeV. 792 MeV. July-December 1981 PHOQIIESSATLAMPF 31 Los Alamos National Laboratory p-p Elastic Scattering at 800 MeV we have conducted several experiments that provide (Exp. 563, HRS) needed small-momentum-transfer N-N data for phase- (Univ. of Texas at Austin, Rutgers Univ., Los Alamos) shift analysis. Spokesman: G. W. Hoffmann (Univ. of Texas at Austin) Experiment 563 obtained high-quality elastic differential-cross-section data for p-p at 800 MeV for To determine the appropriate nucleon-nucleon am center-of-momentum scattering angles 6-90°. Before this plitudes needed for microscopic analysis of proton- experiment the only other 800-MeV data in existence nucleus data, it is necessary to have good nucleon- were from Willard et al., and it was believed that these nucleon (p-p and p-n) data to sufficiently constrain the data were incorrect because of a number of cross- phase-shift analyses. In addition, because it is the small- normalization checks made at HRS over the years. The momentum-transfer parts of these amplitudes that are re Exp. 553 data are shown in Fig. 1, along with the quired for the Kerman-McManus-Thaler (KMT) calcula Willard data, forward-angle data from two other recent tions, the appropriate N-N data must correspond to LAMPF experiments (Exps. 15 and 289), and a recent small-momentum transfer. Gatchina (Andreev) experiment. The absolute normaliza Because the N-N work in Areas B and EPB tended to tion of the Exp. 563 data was obtained at 14° (cm.) by be constrained to medium- to large-momentum transfer, 0 4 ecm . 12 16 T- -T- 50 ^^^^w^w^w^,,, • THIS EXPERIMENT a WILLARD, etal. o ANDREEV • EXP 289 - SOLUTION WI81 40 60 9c.m.(deg) Fig. 1. The new Exp. 563 p-p elastic cross-section data at 800 MeV are compared with other data sets and with a phase-shift prediction. 32 PROGRESS AT LAMPF July-December 7981 Los Alamos National Laboratory •Phase-shift solution WI8I (Arndt) + -Phase-shift solution 3F8I (Arndt) P P 800 MeV Im(A) ©c.m.(de9) Fig. 2. The solid curve is the phase-shift solution obtained using the new data and the dashed curve is the solution before the data were incorporated in the data base. normalizing to the Exp. 289 and Gatchina data, which base. The fit is excellent over the entire angular range. agree at this angle. However, as seen in Fig. 2, the important Im(a) and The expected gross discrepancy with the Willard data Im{c) amplitudes obtained from the phase-shift analysis is clearly evident from Fig. 1. The solid curve is a recent incorporating the new data (solid curves) are ly obtained phase-shift prediction (solution W181) of insignificantly different from the results obtained Arndt incorporating the new Exp. 563 data in the data previously (dashed curves) without these data. July-December 1981 PROGRESS AT LAMPF 33 Los Alamos National Laboratory Search for Giant Monopole and Giant Magnetic using LineX strippers, thus eliminating beam halo Dipole Excitations at 0° without use of Line C collimators; slit scattering from (Exp. 630, HRS) LineC collimators was found to be disastrous at the (Los Alamos, Univ. of Minnesota) focal plane. Once a clean beam was delivered to the Spokesmen: J. B. McClelland, J. M. Moss, and T. Carey target, the next major effect was the horizontal position (Los Alamos), and N. Hintz (Univ. of Minnesota) of the beam on target. The size and shape of the ob served background changed dramatically over the range Progress has been made on the development of the of HRS acceptance, probably associated with pole-face HRS facility to allow measurement of (p,p') reactions at scattering in the HRS dipoles. 0°. This development was motivated by strong interest in Special hardware was constructed for the 0° inelastic identifying giant monopole and dipole excitations in measurements. To allow for unobstructed passage of the nuclei. It is often the case that, at the smallest nonzero beam at the focal plane, single-ended trigger scintillators angle at which cross sections can be measured (~3.5°), were installed with phototubes at the low-energy end. the cross section for these states has dropped by a factor Special focal-plane wire-chamber supports were designed of 5 from that at 0°. to allow the beam to pass as close as possible The method for performing this type of measurement (~76.2 mm) to the active region of the chamber. For involves transmission of the unscattered beam at 0° beam monitoring purposes an ion chamber and beam through the spectrometer and above the focal-plane profile chamber were installed downstream of the focal- detectors such that only excited states of the target nuclei plane detectors. are registered in the detectors. At this level of development we were able to obtain the The goal is to devise a system free enough of very clean spectrum in Fig. 1 of nC(p,pr) at 500 MeV background to be capable of measuring beam-target in over the excitation region of 6-27 MeV. Very noticeable teractions at the few-parts-in-10B level with respect to the in this spectrum is the 1+, T = 1 state at 15.11 MeV. It is beam. During three development runs, we have identified possible to obtain the ratio of this state to the 1+, T= 0 the major limiting factors in attaining this goal, the state at 12.71 MeV, which gives a fairly model- foremost being beam quality at the target. It was independent measure of the strength of the central-to- necessary to tailor the H" beam before entry into Line C tensor force at 0°, because the T = 0 state is excited primarily by the tensor exchange whereas the T= 1 state 300 SOO 10.00 15.00 20.00 25.00 MISSING MASS (MeV) Fig. 1. The nC(p,p') spectrum taken at 0° with a 497-MeV incident proton beam. 34 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory is excited by the central part of the force. A distorted- obtain the details of the structure. Providing such data is wave-impulse-approximation (DWIA) calculation using important for refining the quasi-elastic production the Love-Franey force gives a value of 10 for this ratio, doorway model and for our further understanding of the whereas the preliminary data yield 14 ± 2. A "'Zr spec reaction process. Also, analyzing-power data analogous trum has been measured at 500 MeV and is being to the cross-section data would be very useful for a more analyzed at the present time. quantitative investigation of these important processes at Improvements being considered for future runs in 800 MeV. volve active collimators before and after the target, since We expect the (p,p) inclusive analyzing powers ob we feel we are still seeing remnants of the elastic scatter tained for all N~Z nuclei to be close to the weighted ing (beam) being degraded into the region of excited average of the analyzing powers for p+p and ~p + n. states, as well as perhaps some target frame interactions. Specifically, (1) we expect Ay^p') on the quasi-elastic peak for any iV~Z nucleus to be the same as the weighted average of the known analyzing powers for Reactive Content of the Optical Potential at 800 elastic p + p andp + n; (2) in the pion-production region MeV (Phase II) the analyzing powers for N =; Z nuclei should be similar 2 (Exp. 642, HRS) to those for H(p,p'); and (3) since two types of A (Univ. of Texas at Austin, Rutgers Univ., Los Alamos) production are occurring (leading to the detection of Spokesmen: G. W. Hoffmann (Univ. of Texas at Austin)deca y and recoil protons), the Ay(Q,p') data might help separate these processes. Here, as in (2), for #~Z and J. McGill (Los Alamos) nuclei the structure in ^(G.p') should be like that for 2 The 800-MeV (p.p') inclusive data obtained in Exp. H(p,p'). 470 indicate that the reactive content of the optical Observations consistent with these ideas will provide potential at this energy stems from two-nucleon quasi- even more support for the quasi-free picture of reactions free processes. This in turn provides justification for us at 800 MeV and the use of the impulse approximation at ing the impulse approximation as a starting point forp + medium energies. Agreement with expectations might nucleus calculations at 800 MeV. also suggest that inclusive data in the quasi-elastic region If we look for details in the inclusive spectra we note can be used to directly obtain effective amplitudes for the the possible existence at forward angles of two broad p + nucleus microscopic calculations. structures in the region identified with pion production. We plan to continue our study of the reactive content One peak appears to be located about 350 MeV/c from of the optical potential at 800 MeV by providing these 2 12 12 the quasi-elastic peak, whereas a second, broader peak is additional data forp + 'H, H, and C. The data for C located roughly 600 MeV/c from the quasi-elastic peak. have been obtained and are shown in Figs. l(a)-(d). The 2 Because the inclusive (p,pr) experiment detects both 'H and H data will be obtained in the immediate future l recoil and decay protons, it may be that these two struc using .:H2 and LD2. 12 tures map to each type of proton. The recoil-proton spec Because the interpretation of thep + C data must be 2 trum is expected to be more like that for a two-body made in terms of the p + 'H and H data, a comprehen reaction (p + iV —»- p«coU + A) than the decay-proton sive discussion of the physics to be learned from the data spectrum (p + N->• p,KOl, + pdec,y + n), which is more shown in Figs. l(a)-(d) must await completion of the ex like that for a three-body final state. It is possible to es periment. We do note, however, that the values of the I2 timate the relative yield from >ecoil and decay protons analyzing power forp + C on the peaks of the quasi- using the isobar production model of Wallace; we find elastic parts of the spectra are equal to the weighted 29% recoil and 71% decay. It does appear from the data averages of the corresponding (free) p+p and p + n that the first structure is narrower and smaller in analyzing powers (if the small background is properly magnitude than the second. accounted for) and that a significant structure in the Unfortunately, Exp. 470 did not cover the "two peak" analyzing power is seen just above pion threshold for all region of the (p,pr) spectra with sufficiently fine steps to four inclusive spectra obtained between 5 and 20°. July-December 1981 PROGRESS AT LAMPF 35 Las Alamos National Laboratory I.0C (•) l2 (6) P + c : "• 1.0 p '2C 800 MeV " * + 800 MeV ! 5° i 11° V. t •v 1 0 J) 0 ..bis 0 . J a b •a 1; " 0.2- l2 0.1 c(P,p') * 9|ab = 5° 2 0.1 T ' C(p,p') 0,3 0.2 -0.! 1400 1000 600 0.1 ••"••, p'(MeV/c) Hf{i i U* -0.1 1400 1000 600 200 p'(MeV/c) (c) _ i.o - «i) > p +'2C a> P*,2C 800 MeV 800 MeV 15° 20° E D. b •O N °1 T3 cs o.i- 0.1 ,2 0.3- *'i C(p,p') 0.3 i C(p,p) 9|nK=l57lab ° 1 e7laJnbu=2o ° 0.2- 0.2 ii !•, 0.1 0.1 f i '•l * I t 1 I ^ -0.11 -0.1 1400 1000 600 1400 1000 600 p'(MeV/c) p'(MeV/c) Figs. l(a)-(d). Inclusive (p,p') cross sections and analyzing powers obtained for 12C at 800 MeV. 36 PROORESSATLAMPF July-December 1981 Los Alamos National Laboratory 1 Asymmetry Measurement of the (p.n ) Reactions 9 10 Tp> 650 MeV on 9Be at 650 MeV B«(p,ir+) B« - 4;g.«. <}>3,37M»V (Exp. 649, HRS) (Univ. of Texas at Austin, Massachusetts Institute of •Bel**-)10 C Technology, Univ. of Minnesota) \ ^5.3 M»V Spokesman: Bo Hoistad (Univ. of Texas at Austin) The {p,ii) reaction process has resisted many attempts during the last years to be understood in detail. There is 10 20 30 40 50 as yet no simple model that can explain the most salient features of the experimental data. The difficulty in inter - preting the data at intermediate proton energies is due to the fact that the data show no clear signature of either - the reaction dynamics or the nuclear wave functions in 1 h 1 volved. Instead, the large variety in shapes and - It magnitudes found in the differential cross section is probably due to an interplay between the reaction diagrams and the nuclear structure. This is clearly seen in the data obtained at low energy, but to a lesser extent Fig.l. in the high-energy data where the influence of the nuclear Analyzing powers for n+ and n~ production at an structure is suppressed. incident proton energy of 650 MeV as a function of One important piece of information about the reaction cm. angle. mechanism is obtained from measurements of the analyzing power Ay. Early data at 200 MeV from TRIUMF indicated similarities between the elementary Fig. 1 refers to the transition to the peak at 5.3-MeV ex pp —> dn amplitude and the (p,7i) reaction on nuclei. citation energy. It is interesting to note that the low- Later data, however, show much larger sensitivity to the energy data from the *Be(p,jc_)10C reaction show nuclear structure involved, and any resemblance to the negative Ay for forward angles. In fact, an attempt to ex pp -*• dn data is difficult to see. At energies above the plain the negative Ay in this reaction has been made for (3,3) resonance no data exist for targets with A > 2. The the low-energy data.1 Assuming that the elementary aim of the present experiment is to measure the analyz reaction is a pn —*ppn~ process and that the two final ing power in both JI+ and n~ production on 'Be, leading 10 10 protons couple to spin zero, it is possible to use argu to a description of final states in Be and C, respec ments based on simple angular-momentum coupling to tively. predict opposite sign of Ay for (for example) the The first half of this experiment was run in April 1981, 12C(p,7T)130 reaction (A/ = 3/2) and the 9Be(p,jr)10C and the preliminary results are shown in Fig. 1. The + reaction (A/ = 1/2). This result is confirmed by ex analyzing power for n goes through a clear minimum at perimental data at low energy. However, as seen, the rather small angles. This result bears no resemblance at high-energy data give another result This is perhaps not all to thepp —*• dn data at the same energy, which show surprising since the subthreshold arguments also assume positive analyzing power for all angles. However, data a directional preference of the bound neutron in its Fermi from the pd-^-tn reaction show a negative minimum in motion with respect to the incident proton. Such assump Ay, but at a larger angle. Another feature in the 9 10 tions are certainly invalid at high energies. Be(p,n) Be data is the indication of a nuclear structure From the (p.rc1) data obtained in this experiment we dependence, since the positions for the minima of Ay conclude that the analyzing power is sensitive to the inci from the transitions to the ground state and 3.37-MeV dent energy, the nuclear final state involved, and the state are separated by about 10°. 9 10 charge of the pion. It is therefore likely that these Regarding the Be(p,n~) C reaction, only one angle measurements contain important information about the has been measured so far. Transitions to all final states in reaction mechanism. In phase II of this experiment, the 10C yield positive analyzing power. The datum point in July-December 1981 PROGRESS AT LAMPF 37 Los Alamos National Laboratory 40 + angular distribution of Ay will be extended to larger The inclusive Ca(ii ,2y) reaction at 50 MeV ap angles. peared to be a good candidate to use in a search for this phenomenon because of (1) the large atomic mass of REFERENCE 40Ca, (2) the high nuclear transparency of 50-MeV pions, (3) the natural ability of a pion to become virtual after in 1. M. C. Green etai., Indiana University Cyclotron Facility (IUCF) teraction with the nucleus, (4) the ability to reach 300- Newsletter 29, 2 (October 1981). MeV/c momentum transfer, and (5) the use of many final states to remove uncertainties in nuclear wave functions. Even in the absence of any observable precursor jt±-Nuclear Elastic Scattering at Energies Between phenomenon the measurement of this reaction presents 30 and 80 MeV several interesting challenges. Some of the processes con tributing to the cross section involve understanding pion (Exp. 561, LEP) absorption far off the mass shell. Additionally, the role of (Virginia Polytechnic Institute and State Univ., Oak the A resonance must be accounted for in the radiative Ridge, Los Alamos, Univ. of South Carolina, capture, a phenomenon usually ignored in the interpreta Massachusetts Institute of Technology, Univ. of tion of stopping experiments. Maryland) During July and August 1981 (cycle 30), 5 weeks Spokesmen: M. V. Hynes (Los Alamos), F. Obenshain were devoted to measuring the 40Ca(n+,2y) reaction. (Oak Ridge), and M. M. Blecher (Virginia Polytechnic About 3 weeks of this time were devoted to taking data. Institute and State Univ.) The two photons were detected using the LAMPF n° spectrometer. As the reaction is expected to have a very A run in November started the last round of this small cross section, random backgrounds were expected survey-like experiment in which the study of elastic scat to be troublesome, but the preparations for three an tering from a series of isotopes will provide constraints ticipated problems worked very well: (1) shielding for the on the theoretical understanding of the isovector part of required close geometry protected the counters ade the n-nuclear interaction. We completed the measure quately; (2) two-photon backgrounds from 7t° decay ments on 12C, 13C, and 14C at 80- and 65-MeV n*. were completely eliminated by placing the detectors in side the kinematically forbidden region for n" decay; and (3) random counts from two photons produced by two A Search for Nuclear Critical Opalescence Using + different pions in the target were rejected by a target the Reaction *°Ca{n ,2y) hodoscope designed to observe multiple particles over a (Exp. 541, LEP) large beam spot. The result of this apparatus was com (Los Alamos, Univ. of Louvain, Univ. of North plete elimination of cosmic rays beyond the measurable Carolina) limit and a random background from the beam corre Spokesman: M. D. Cooper (Los Alamos) sponding to a singles flux of seven high-energy photons per second. Critical opalescence is the premature onset of pion-like The beam hodoscope performed remarkably well. It behavior in real nuclei induced by the proximity of a consisted of 40 scintillation counters ~1.5 mm thick by pion-condensed state at roughly twice nuclear-matter 8 mm wide by 100 mm long. Short light guides connect density. The nature of the precursor of the condensed ed the scintillators to 19-mm (3/4-in.) Amperex 1911 state is such that the pion field, which is always present photomultiplier tubes. No rate effects were noticed up to around nuclei, is enhanced by medium corrections. The 106particles/s average. Individual counters were charac enhanced field introduces a spin-isospin correlation terized by better than 99.5% efficiency, 15% pulse-height among the nucleons. Because the density is below resolution, and 1.5-ns time resolution. The gap between criticality, the range of the pion field is still fairly short, counters was always <38 urn. and only modest effects in real nuclei are expected. This The use of the beam hodoscope is illustrated by two theoretically predicted phenomenon is manifested by en idealized events shown in Fig. 1, which is a scale drawing hanced cross sections for processes involving virtual of the hodoscope arrangement of the active area of the pions of low energy and momenta near 300 MeV/c. counters about the target, the solid rectangles indicating 38 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory •] I cm U— (a) I I I I I CALCIUM TARGET a E 10 ns EARLY IN TIME IN TIME 10 ns EARLY BOTH 7 BOTH? I L (b) E= 3 ' • • CALCIUM TARGET 3 E IN TIME IN TIME IN TIME IN TIME TOP 7 BOTTOM 7 BOTTOM y TOP 7 TOP 7 10 ns EARLIER THAN BOTTOM 7 Fig. J. Idealized events in the target hodoscopes. The figure illustrates the principle of operation of the hodoscope. struck counters. Figure 1(a) displays a promising can TABLE I didate where a pion disappears in the target and is in time coincidence with both x rays; another extraneous PROBABILITY OF HIT COMBINATIONS particle goes through about 10 ns earlier. Figure 1(b) portrays a rejected accidental in which two pions interact Measured Data in the target, each producing one photon in a gamma- Upstream Particles detector arm. n A Monte Carlo simulation of the hodoscope com n\ pletely characterized the performance, with the added assumption that 2% of the events fired neighboring coun 4.74 X 10-4 0 ters. The quality of the agreement is reproduced in 0.8836 0.0455 9.95 X 10-" h 4 Table I, which tabulates the probability of producing a 0.0545 0.0118 5.68 X 10- pattern of n particles upstream and m particles o 0.0013 0.0011 Q 1.45 X 10-" downstream for a given trigger of the y detector. The agreement with experiment is excellent except for very Monte Carlo Results rare off-diagonal events. Upstream Particles Data were taken at central momentum transfers at n\n 140 and 280 MeV/c with a resolution (FWHM) of 35 MeV/c. It is our impression that the reaction was ob 4.45 X 10-" 0 served at both settings with about 50% background. The 0.8793 0.0504 2.02 X lO-4 expected ensitivity above background should be 5 nb/sr2. 0.0538 0.0132 9.75 X 10~* Since the data are still being analyzed, no conclusions 5.46 X 1 July-December 1981 FROQRESSATLAMPF 39 Los Alamos National Laboratory Elastic Scattering of Pions in the Energy Range 20- (*' + °ff t[E{k\q,q-} oc b0(E) 50 MeV (a2 + q^a2 + q'2) (Exps. 29/54, LEP) (Oak Ridge, Los Alamos, Massachusetts Institute of (k2 + a2)2 Technology, Univ. of South Carolina, Tel Aviv Univ., + btf) 2 2 2 2 a • q Virginia Polytechnic Institute and State Univ.) (a + 9 )(a + q' ) Spokesman: R. Burman (Los Alamos) A program of low-energy, pion-nucleus elastic- The E and k are the on-shell energy and momentum, scattering measurements has been in progress at and q,q' are the off-shell initial and final momenta. The LAMPF for some time. With the measurement of data at range parameters o0 and a, for the nN interaction are 20 MeV it is now complete. equal, a0 = a, = 500 MeV/c. The s- and p-wave The research reported here involves the scattering of parameters b0 and 6, were varied to obtain a minimum 2 20-MeV positive pions (rt+) from 12C, 160, 40Ca, 90Zr, x . 120 and Pb. These data, together with data from previous In Fig. 1 we show a plot of the parameter Imb0 as a measurements at 30, 40, and 50 MeV, yield a rather function of energy for each of the nuclei 160,40Ca, 90Zr, complete description of the energy and mass dependence and 208Pb. The values at 30,40, and 50 MeV were taken of the pion scattering in this low-energy region. from our previous work. As can be seen from the figure, As we demonstrate, the absorptive s-wave strength is the absorptive s-wave parameter at 20 MeV is much much stronger at 20 MeV than would be expected from the 30- to 50-MeV data or from the predictions based on free rc-nucleon amplitudes. A theoretical method based ORjn.-DWG~Bl-12486 on parameters obtained from pionic-atom data has been successful in constructing an optical potential that correctly predicts our measured cross sections without any adjustable parameters. This is in agreement with the conjecture that the method accurately predicts low- energy data, 30 and 40 MeV, but begins to break down at 50 MeV. The elastic cross sections were determined at 17 « 2 angles in 2-angle sets with plastic-scintillator telescopes u. and at forward angles with detectors sensitive to the Jt-uv decay. The telescopes were kept fixed at lab angles of 90 and 100° during the entire experiment to provide con sistency checks of the calibration. In all cases, with the exception of one angle set for lead, the relative nor malization was better than 4%. The differential cross sections were calculated, taking into account the finite angular acceptance and efficiency of the telescope detector systems. Multiple scattering in the target at a given angle, pion decay in flight, and reac 20 40 60 80 tions in the detector were also taken into account in the calculation. Typically, all these effects amounted to a 10 Lab Energy (MeV) or 20% correction to the cross sections. The statistical uncertainties were ~7%. Fig.l. A phenomenological optical-model analysis was The absorptive s-wave strength Imb„ is shown as a carried out for the measured angular distribution for function of energy for 160, *°Ca, mZr, and mPb. each target. The form of the nN (matrix used to The curve is a theoretical calculation using pion- calculate the optical potential was nucleon amplitudes. 40 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 7 OR.SI-DWG-m-12481 The curves shown in Fig. 2 were calculated by o ^Pb Professor McManus. We have plotted our 20-MeV data on the same graph without any relative normalization. The agreement between theory and experiment is quite satisfactory. Study of Isovector Giant Resonances with Pion Charge Exchange (Exps. 412, 525, and 607, LEP) (Tel Aviv Univ., Los Alamos, Case Western Reserve Univ.) Spokesmen: H. W. Baer and J. D. Bowman (Los A lamos) Much progress has been made in the analysis of the (it*,?!0) data taken in March-April 1981. The Monte 0 20 40 60 80 100 120 140 160 1B0 Carlo simulation of the n° spectrometer solid angle has been thoroughly investigated and checked against data on the n'p —>• n°n reaction. The spectrometer acceptance Fig. 2. as a function of energy is understood to 10% absolutely The data shown are the same as Fig. 1. The curves and a few percent relatively. Computer programs have were calculated according to the model of Strieker, been written that allow us to correct the measured spec Can, and McManus. tra for relative acceptance; to shift, smooth, add, and subtract histograms; and to perform peak fitting using measured line shapes. All the data are replayed and are available as normalized n" kinetic-energy spectra larger than those for the other energies. The curve shown (d1ddQ.dT) vs scattering angle. The data set is for 164- is a theoretical prediction based on n/V-interaction data; MeV beam energy, is in the angular range 0-30°, and in it, too, is much lower than the values obtained from our cludes targets 2H, 12C, 40Ca, 90Zr, ,20Sn, and 208Pb. analysis. Preliminary results were discussed in the June 1981 The explanation for this increase in Imb at 20 MeV is 0 Progress Report (LA-8994-PR). We discuss here select not obvious, but it could be related to the penetrability of ed new results derived from the more recent data the pion into the nuclear volume and the many-body analysis. aspects of the nuclear interaction. The work of Strieker, Carr, and McManus is another approach to the problem of obtaining a pion-nucleus optical-model potential. These authors have developed Giant Dipole Resonance (GDR) an optical model with parameters obtained from pionic- n 40 atom data. Their model was compared with positive-pion C and Ca. These targets serve the purpose of es elastic-scattering data at 30, 40 and 50 MeV. The agree tablishing the magnitude of the GDR cross sections ment between theory and experiment is very good at 30 where isospin splitting and blocking do not broaden and and 40 MeV, but at 50 MeV the model appears to break reduce the signal, and where we can compare (n~,n°) + down, since some of the detail seen in the experiment is spectra with (Jt ,Jt°) spectra to get a better understand not reproduced. ing of the continuum. PROGRESS AT LAMPF 41 July-December 1981 Los Alamos National Laboratory 100 120 HO 180 100 120 140 160 n° KINETIC ENERGY (MeV) Fig. 1. The measured n° spectra for the 40Ca(7t+,re°) reaction at 164 MeV. The arrow marks the expected position of the analog of the giant dipole resonance in i0Ca at 20-MeV excitation. The solid line is the smoothed, but nonrenormalized, 3° spectrum. It was used for the background shape at each angle in the GDR cross-section determinations. 40 + 4 The Ca(7t ,7t°) spectra at six scattering angles are AT(ANALOGS) ~ AQ = A£C( °K) shown in Fig. 1. A very clear manifestation of the GDR is observed at the expected n° energy. Inspection of + A£ (40Ca) - 2A, c np Fig. 1 shows that the continuum remains constant over the angular range of this experiment. 40 40 The solid line shown with each spectrum is the where A£C( K) =7.13 MeV and A£c( Ca) = 7.45 MeV smoothed 3° spectrum without any renormalization. are the Coulomb displacement energies1 and A„„ =• One sees that this line gives an excellent description of 1.293 MeV is the neutron-proton mass difference. This the continuum between 100 and 135 MeV for the spectra gives AT= 12.0 MeV for the expected shift in the GDR 3-22°. Therefore, a reasonable measure of the shape of states. The measured displacement for the 14° spectra is the background under the GDR is the 3° spectrum 12.1 ± 0.4 MeV, where the error represents the statistical where the contribution of the GDR is expected to be at a uncertainty. One sees that the observed peak positions minimum. The same assumption was used to analyze the and the displacement of the two peaks are consistent 40Ca()t",7t0) data (Fig. 2) for the GDR peak areas and with identifying them as the GDR analogs. centroids. The excess counts in a 12-MeV interval centered The it0 kinetic energies for the two states of an isospin about the expected position of the GDR were used in the triplet produced by the 40Ca(n±,7t°) reaction are related determination of the cross sections. A Gaussian function by was fit to these counts to determine the peak centroids 42 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 2 0.6 i strong absorption model for a AL = 1, spin-independent transition on an N— Z nucleus, the angular distribution - *V>>. V°Ca< has the form 0.4 - \" <> rfo(B) = pk2J2(qR) 02 dQ -M \ i where q — h[k-k'\ is the momentum transfer and R is the interaction radius. A value of R = 4.80 F was used, which is the average value of the interaction radii at 164 MeV deduced3 from an analysis of n+ and n~ elastic scattering on 40Ca. Because of the Coulomb energy dif ference of the two final states, the q values and, therefore, j]{qR) are quite different at 0°; for the (n+,n°) reaction, q = 26 MeV/c and j\(qR) = 0.093, and for the (7T,7t°) reaction, q = 13 MeV/c and J](qR) = 0.023. The max imum J2i(qR) = 0.34 occurs at 15.4° for (TI+.7I0) and at fig. 2. The measured 40Ca(7t±,7:0) cross sections compared with the function (3[J^(qr) — J^0)] expected for a AL = 1 transition. The error bars reflect the statistical error associated with the model- dependent analysis of the background shape. and widths. For the three angles, 10, 14, and 18°, the W 105 130 156 K> 105 190 155 IK peak centroid is constant to better than ± 1 MeV. The widths appear to be angle dependent, with a minimum ir° KINETIC ENERGY (MeV) width observed at 14°. The fits to the data at this angle gave (FWHM) 6.6 ± 0.7 MeV for the (Jt+,7i°) spectrum fig. 3. and 6.1 ± 0.5 MeV for the (7i~,7t°) spectrum. These The measured n° spectra for the nC(n~,n") reac values are larger than the 5.0 ± 0.2-MeV instrumental tion at 164 MeV. The arrow marks the position resolution and are consistent with a GDR width of 4 ± corresponding to 23-MeV excitation in nC. The 2 MeV (FWHM). solid line is the smoothed, but not normalized, 3° The extracted angular distributions for both the spectrum. It was used for the background shape at + (7t ,7t°) and (ft~,7i°) reactions are displayed in Fig. 3. In a each angle in the GDR cross-section determina tions. July-December 1981 PROGRESS AT LAMPF 43 Los Alamos National Laboratory 16.0° for (n~,n°). Since the GDR cross sections were approximation calculations and eikonal-model extracted by subtracting the 3° spectra, the proper calculations6 with collective form factors indicate that functional form to compare to the measured angular dis such 2" states have angular distributions that have a first tribution is $\J](qR) - ^f(3°)|. This function normalized peak near 30°. The 1 ~, AS = 1 states have a maximum to the central three points in each of the angular distribu at 0°. Further studies of this feature are of interest. tions is shown by the solid lines in Fig. 3. Values of the The 40Ca(7i±,jt°) data constitute the first observation + deduced (3 are 2.55 and 2.50 mb/sr for the (7r ,jt°) and and angular distribution measurements of the GDR in (jT,7t°) reactions, respectively. pion single-charge-exchange scattering. The favorable To see if the magnitudes of the measured cross sec signal-to-background conditions, the sharply oscillating tions are consistent with previous knowledge of the angular-distribution shape, and the seemingly trans GDR, we calculated the value of p using the Goldhaber- parent theoretical interpretation of the cross sections Teller4 form of the transition density, make the study of the GDR with the {^.T.0) reactions look quite promising. 2 3 2 2 Ap, = hc(8nNZY' (iA hto mpc )~" nC(n~,n°). The measured spectra (Fig. 3) show a peak rising above the continuum at angles 10-28°. The smoothed 3° spectrum is shown with each measured spectrjm. One sees that for angles 10-20° the spectra rise above the solid line in the region 115-150 MeV (cor 12 which is normalized to exhaust the classical E\ sum rule, responding to 15-50-MeV excitation in C). This result 40 + where hco is the excitation energy, dpjdr is the differs from what was observed in the Ca(7t ,7i°) reac derivative of the nucleon density p0 = p„ + p_, Ylm is the tion where the continuum remained constant from 3-28°. l2 + spherical harmonic of order 1, A is the atomic number, The C(7t ,7t°) spectra do remain constant near the value and mp is the proton mass. Inserting this transition den of 30-ub/sr MeV between 95 and 110 MeV at all scatter sity into an eikonal model for the scattering amplitude ing angles. and then making several numerical approximations in As a first analysis of the I2C GDR differential cross evaluating the resulting integrals leads to the value sections, we followed the prescription used for the 40Ca (3 = 2.8 mb/sr. The good agreement between the analysis. The excess counts above the 3° spectrum in an measured cross sections and the model value gives a first interval centered on the observed peak position were indication that the excitation of the GDR in pion charge- taken for the peak areas. For 40Ca the width of this inter exchange scattering near resonance energies does not in val was 12 MeV. Comparison of the 12C and 40Ca spec volve pathological features, rather, it may be understood tra at angles near the maxima of the GDR cross sections quantitatively as a single-step charge-exchange scattering shows that the 12C GDR peak is broader. Therefore, a at the nuclear surface. The same radial dependence and large interval of peak area integration is appropriate. An normalization of the transition density also work for El interval of 16 MeV extending from 19-31 MeV in 12C photon absorption and Jt charge exchange. was used. The centroid of this peak area in the 22° spec A secondary feature of the data is the angle-dependent trum occurs at 145 MeV, which corresponds to 25 MeV 12 broadening of the GDR peak (Fig. 1), which is par in C. ticularly noticeable in the 22-28° spectra of Fig. 1. These The angular distribution obtained with this model of data are consistent with excitation of states near 25 MeV the background is shown in Fig. 4. The function $[J\(qR) in '"'Ca. The angular distribution for these states appears — y2(3°)J with value P = 2.45 mb/sr is compared with to have a minimum near 14° and to rise at the large the data. The value i? = 3.16F was used. This is the angles. An intriguing possibility, consistent with the data, average of R+ and R~ deduced from the position of the is that this excess cross section is due to transitions with first minimum of elastic n+ and JI~ scattering at 180 AL = 1, A5= 1 (spin-flip), producing 1~ c 2~ states. MeV. The maximum value of J\(qR) for this value of R Such states, with predominant particle-hole configura occurs at 25°. One sees that the rise of the GDR cross tions [fsplds/i'i are expected5 at several million electron volts above the GDR. Both distorted-wave-impulse- E. R. Siciliano, private communication (1981). 44 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory • a forward-peaked angular distribution of the form da (0) J2 (gR) "rffi 0 • a 0° cross section da da (0) of about 500 ub/sr; • a radius parameter R, which is the same as the 20 30 radius parameter determined by elastic pion scatter 0LAB(deg) ing; • an excitation energy hco of ~170 MeV x A~m, the Fig. 4. hydrodynamical estimate for the energy of the Angular distribution for the GDR peak in the reac isovector monopole resonance in the target nucleus; tion I2C(JT,JI°)X. The solid line is a fit to the func and tion p|jfaR) - J2(3°)|. •a width of a few million electron volts. These cross-section estimates were carried out using a Tassi form for the transition density. A sum rule nor section from 3-22° follows quite closely the j]{qR) malization with blocking determined the amplitude of the dependence. The 22 and 28° differential cross sections transition density. are expected to be nearly equal from the J\(qR) function. The 28° data point falls below the 22° point by 88 ± 2 47 ub. Data at larger angles are desirable to establish ATI0 = Ghc (2mPC A hco)" that the observed peak follows the J\ shape between 25 and 50°, and thereby to establish the AiL = 1, AS = 0 nature of the transition. It is interesting that the preliminary value of the max (*.+-£) imum of the GDR cross section is 2.45 X A(25°) = 0.8 mb/sr. This is close to values 0.85 and 0.87 mb/sr obtained for the i0Ca(n~,n°) and 40Ca(jtV) reactions, Here G is a blocking factor (0.73 for 120Sn) and July-December 1981 PROGRESS AT LAMPF 45 Los Alamos National Laboratory 11.0° 120 120 120 80 eo 40 #f* 40 > I1" \ 2 V', .V 100 120 140 160 100 120 100 120 140 160 120 Sn(TT-,TT°), 165 MeV 100 120' 140 160 100 120 140 160 TT° KINETIC ENERGY (MeV) Fig. 5. The double differential cross section d2a/dQdE (\xblsr MeV) for the reaction I20Sn(7t~,Jt°)X as a func tion ofn° kinetic energy Tno for scattering angles between 4.5 and 22.0°. The incident iC kinetic energy is 165 MeV. monopole and dipole peaks. The dipole results are com 3. P. Gretillat, J.-P.-Egger, J.-F. Germond, C. Lunke, E. Schwarz, C. pared with existing experimental data and the monopole Perrin, and B. M. Preedom, Nucl. Phys. A364, 270 (1981). results are compared with theoretical expectations. The agreement between the present data and predictions 4. M. Goldhaber and E. Teller, Phys. Rev. 74, 1046 (1977). made before the experiment was done is remarkable and supports the first experimental observation of the isovec- 5. T. W. Donnelly and G. E. Walker, Ann. Phys. 60, 209 (1970). tor monopole resonance. 6. A. Gal, TRIUMF preprint (1981). REFERENCES 7. J. D. Bowman, M. Johnson, and J. Negele, Phys. Rev. Lett. 46, 1614 (1981). 1. W. J. Courtney and J. D. Fox, At. Data Nucl. Data Tables 15, 141 (1975). 8. K. Shoda, Phys. Rev. 53, 552 (1979). 2. J. D. Bowman, M. Johnson, and J. Negele, Phys. Rev. Lett. 46, 9. A. Bohr and B. R. Mottelson. Nuclear Structure, Vol. 2 (Benjamin 1615 (1981); and J. D. Bowman and M. Johnson, to be published. Reading, 1925). p. 671. 46 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 120Sn(n-.n»), 165 MeV 4.5-11.0° Fig. 6. The difference between the 4.5 and 11.0° spectra for the reaction 120Sn(7t_,7t°)X. 140 I5D ISO 170 n° KINETIC ENERGY (MeV) 600 1 100 —- / < >\ (b) > > J3. UJ r •a Ct •p » / -100 i I 10 20 SCATTERING ANGLE (deg) SCATTERING ANGLE (deg) Figs. 7(a) and (b). (a) Areas for the monopole peak in ,20Sn(ji~,jt°)X extracted from fits to difference spectra. The 11.0° spectrum was used as a reference. The solid line is a fit to the form p[J^(qR) — J|(l 1.0°)]. (b) Areas for the dipole peak in 120Sn(7T,jt0)X extracted from fits to difference spectra. The 4.5° spectrum was used as a reference. The solid line is a fit to the form p[jJ(qR) — Jj(4.5°)]. July-December 1981 PROGRESS AT LAMPF 47 Los Alamos National Laboratory TABLE I SUMMARY OF DEDUCED PARAMETERS FOR THE MONOPOLE AND DIPOLE PEAKS PRESENT IN THE 120Sn(»T,rr0)X REACTION DATA Dipole Quantity This Work Other Results Source Radius parameter R 7.5 ± 0.7 F 6.87 F 7t" elastic scattering da (max) 200 ± 40 ub/sr 340 ub/sr Sum rule estimate with blocking (Ref. 8) dif Excitation energy in 120Sn 21.3 ± 0.85 MeV 20.9 MeV Electron scattering (Ref. 8) Monopole Quantity This Work Estimates Source Radius parameter R 7.3 ± 0.6 F 6.87 F n~ elastic scattering da, -(max) 740 ± 85 ub/sr 450 ub/sr Sum rule estimate with blocking (Ref. 7) dO. Excitation energy in ,20Sn 30.9 ± 0.5 MeV 34.5 MeV Hydrodynamical estimate (Ref. 9) Width 7.2 ± 2.0 MeV Few MeV Related widths (Ref. 7) High-Resolution Study of (n+,pp), (n+,pd), and obtained during the last 2 years at the LEP channel using Other (n+,xx) Reactions on 6,7Li, 14N, and 160 two spectrometer systems to detect charged particles in (Exp. 315, LEP) coincidence, are either in the reduction stage or are still (Carnegie-Mellon Univ., Los Alamos, Massachusetts In in the primitive on-line form collected during the stitute of Technology, Univ. of Washington, Arizona monitoring of our recent experiment. The reactions + State Univ.) studied are (n ,xx), where xx can be any combination of Spokesman: William Wharton (Carnegie-Mellon Univ.) two-hydrogen isotopes (p,d,t). We also measured 6,7Li(ji+,HeHe) cross sections. By looking at a large variety of pion-annihilation reac The large cross sections of some of these reactions are tions and doing a high-precision kinematically complete surprising. The 1'Li{n+,pd) cross section is more than experiment, we study the mechanism by which the pion 20% larger than the 7Li(ji+,pp) cross section. Some of annihilates in a nucleus. Pion propagation and annihila our (n+,pd) data were presented and discussed at the In tion inside nuclei is a fundamental but difficult problem diana University Cyclotron Facility (IUCF) Pion Work to understand. shop. ' Because most annihilations involve multiparticle (>3- Our (n+,pp) missing-mass resolution was as good as particle) final states, coincidence experiments are in 1.0 MeV with the channel set at Ap/p = 0.5%. Figure 1 valuable and potentially richer in information than are shows a missing-mass spectrum for the '60{n+,pp)uN single-arm experiments. For this reason we collected a reaction. The dominant peak in the spectrum is the 1+ large amount of high-quality two-particle coincidence state at 3.95 MeV. We also see the 14N, 1+ ground-state data from pion annihilation on light nuclei at several pion transition. This transition is known to involve two units energies between 38 and 90 MeV. The data, which were 48 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory •T 1 1 1 •I -l II i REFERENCE r 3.95 1. "Workshop on Pion Production and Absorption in Nuclei," Ed., R. D. Bent. Indiana University Conf.. October 1981. 160.0 - - A Study of Neutrino-Electron Elastic Scattering (Exp. 225, Neutrino Area) 120.0 (Univ. of California at Irvine, Los Alamos) n" + d -» p + p Spokesman: H. H. Chen (Univ. of California at Irvine) 1- Z 1 . o This experiment, designed to measure v-e elastic scat o tering, completed its first shakedown run during the last 80.0 - week of beam in November 1981. The central detector was completely installed during the summer and autumn. The first 13 of 40 modules of scintillators and the first 13 of the horizontal flash chambers were instrumented. The 40.0 1* cosmic-ray anticoincidence shield, composed of ~600 g.s. I drift chambers, was installed. About 95% of the drift I chambers have been connected to an electronics system that piovides a veto signal for incoming cosmic rays. 0 .. iJ IW1L11....I. ,Vw^ Figure 1 is a diagram of the end view of the apparatus. -30 -20 -10 0 10 MISSING MASS (MeV) Fig. I. 16 + l4 The 0(jt ,pp) N missing-mass spectrum at Tn = 60 MeV, proton angles 60 and 102.7°. of angular momentum that have a 50% probability of be ing either in the internal motion or the center-of-mass motion of the two removed nucleons. By looking at the recoil momentum distribution for the ground-state transi tion, we are investigating the relative strength of pion ab sorption on two nucleons in an internal L = 0 and L = 2 configuration. Between the two 1+ states is a 2.3-MeV 0+, T = 1 state that is very weak in this spectrum. Such a transition would involve pion absorption on a !T = 1, S = 0 nucleon pair rather than on a T= 0, S — 1 pair, which is the case in the 3.95-MeV transition. The ratio of the known spec troscopic strengths and isospin Clebsch-Gordan factors for the 3.95-MeV 1+ and 2.3-MeV 0+ transitions is 3.5. Wmmmmm^mmmzmm The ratio of the cross sections is much larger than this, indicating that absorption on a T= 0, S = 1 pair is much Fig. I. stronger than on a T= 1, S =0 pair. End view of apparatus for v-e elastic scattering. July-December 1981 PROGRESS AT LAMPF 49 Los Alamos National Laboratory The preliminary results of this shakedown run were 3. Because parts of the antishield that cover known satisfying. The central detector worked quite reliably geometrical gaps were not yet part of the overall with very little tuning. Based on feasibility studies made veto signal, the residual trigger rate beyond that with a prototype detector 5 years ago, the background from the backgrounds listed above was attributed trigger rates in the central detector scaled linearly with to veto-system inefficiency. This residual rate of the mass of the detector, adding confidence to our (0.18 ± 0.09) s_1 corresponds to an antisystem in expected rates with the full detector. The background efficiency of ~3 X 10-4. We expect that when we trigger rate with at least three layers of the central detec connect the gap counters to the system the an tor scintillators in coincidence was 585 s~'. With an an tisystem inefficiency will approach the 10-5 level. ticoincidence signal from the drift chambers the rate We will analyze the current data to look for still finer dropped to 0.62 s"1. Cosmic-ray effects derive from effects and to set limits on contributions to the trigger three main components. rate within the beam gate. During the winter and spring 1. Incoming cosmic-ray muons stop within the central of 1982 we plan to instrument the rest of the central detector and subsequently decay after the veto detector, add diagnostics and additional counters to the signal ends. We measured the stopping u+ rate in antisystem, and make several more tuning runs to dis the 13 instrumented layers of the central detector cover and block leaks through the antishield. We expect as (8.0 ± 0.5) s_1. For this run we used an 8-us- to be fully instrumented and capable of looking for long gate, corresponding to 3.6-u+ lifetimes. neutrino events when the beam returns during the sum Therefore, the trigger rate from muons that de mer of 1982. cayed after this time was 0.21 ± 0.01 s_1. The rate expected from the feasibility study for this same _1 condition is 0.26 s . Figure 2 shows an event of A Measurement of the Rare-Decay n° —* e+e this kind in the flash chambers. (Exp. 222, P3) 2. Cosmic-ray neutrons appear in the detector (Los Alamos, Arizona State Univ.) through their interaction with active material, giv Spokesman: R. E. Mischke (Los Alamos) ing highly ionizing recoil protons. By looking at events with large pulse heights in the scintillators + Evidence for the rare-decay n" —*• e e~ has been ob {dEldx per scintillator layer of >3 times minimum tained in an experiment that measured the invariant mass ionizing), we obtained a rate of (0.17 ± 0.08) s~' + spectrum of e e~ pairs produced by 300-MeV/c iC for events of this kind. The feasibility study predict _1 mesons interacting in a liquid-hydrogen target. Interest in ed a rate of 0.16 s . 1 this decay dates back to the first calculation by Drell in 1959. Since then many models have been used to es timate the branching ratio. The effects of vector dominance,2 baryon loops,3 direct quark-lepton coupling,4"6 weak neutral currents,7,8 and Higgs bosons*'9,10 have been included by different authors. In general, most results show only small enhancements over a minimum branching ratio, called the unitarity lower limit.11'12 Thus, the branching ratio is expected to be - — — -• 10 cm • ^ •—« t e i. There has been one previous report13 of a measurement Fig- 2. of the branching ratio for this decay with the result B = 7 Side view of the flash chamber readout showing an (2.2!?;?) X 10- . incoming muon, which stops in the detector and subsequently decays. Peter Herczeg, private communication. 50 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Our experiment used a beam of 1.8 X 107TT/S inci binations to find the best-fit tracks. About one-third of dent on a 5-cm-diam and 25-cm-long liquid-hydrogen the candidate events contained two acceptable tracks. target. Most e+e~ pairs coming from the target resulted Cuts were applied to define a fiducial volume for the ap from 7t° decays, often with a photon being converted paratus and to eliminate accidental coincidences. Accep through Compton scattering or pair production. These table events were required to intersect within the volume pairs always have an effective mass e~. Another source of pairs was the reaction n~p —> Fig. 2. Most of the events with an effective mass 0 MULTIWIRE CHAMBERS •SKBfrfefi*fRS " (IEAEHKOV COUNTER cm Q . 2.Q . *p . jo Fig. 1. Top view of apparatus. The incident beam oftC comes from the left and charge exchanges in the H2 target. The resulting e+e_ from JI° decay are detected by the multiwire chambers, the scintillation counters, and the Cerenkov counter. July-December 1981 PROGRESS AT LAMPF 51 L.os Alamos National Laboratory 10000 14 500 19000 23500 m2 (MeV/c2)2 Fig. 2. Final data sample showing number of events vs in variant mass squared. The open circles are the Monte Carlo Jit to the data. 10000 14500 19000 23500 m2 (MeV/c2)2 fit is shown in Fig. 2; it has a %2 of 49.1 for 47 degrees of freedom. The fit requires 58(±19) JI° —• e+e~~ events. Fig. 3. Normalizing to the contribution from Dalitz decay Decomposition of Monte Carlo fit, which show the 0 events, as determined from the Monte Carlo and the fit, contributions from (a) it decay other than direct + + gives e e~ decay, (b) 7i~p —* ne e~, (c) accidental coin cidences between the left and right sides of the spectrometer, and (d) n° —-»• e+e~. B = (18 ± 6) X 10- REFERENCES The error given is dominated by the statistical uncer tainties in the subtraction of background. We have in 1. S. D. Drell, Nuovo Cimento 11, 693 (1959). vestigated possible systematic effects that could affect 2. I. K. Litskevich and V. A. Franke, Yad. Fiz. 10, 815 (1969) [Sov. the branching ratio. These include our assumptions J. Nucl. Phys. 10, 471 (1970)). about the photon-conversion probability, the form factor 0 + in re —*• e e~y, and various cuts on the data. We estimate 3. M. Pratap and J. Smith, Phys. Rev. D5, 2020 (1972). an overall systematic uncertainty of <10%. Our result is almost four times the unitarity lower 4. A. Soni, Phys. Lett. 52B, 332 (1974), and 53B, 280 (1974). limit. The accuracy is sufficient to give us confidence that we have seen the decay it" —>• e+e~, but not adequate 5. J. D. Davies, J. G. Guy, and R. K. P. Zia, Nuovo Cimento 24A, for us to distinquish between models that predict dif 324 (1974). ferent contributions to the amplitude for this process. 6. J. C. Pati and A. Salam, Phys. Rev. Dll, 1137 (1975). 52 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 7. F. C. Michel, Phys. Rev. 138, B408 (1965). ment measures the momentum spectrum and asymmetry + + of the positrons in the process u —*• e + "v^ + ve. 8. P. Herczeg, Phys. Rev. D16, 712 (1977). The experiment features • a surface muon beam at momentum 29 MeV/c with 9. H. E. Haber, G. L. Kane, and T. Sterling, Nucl. Phys. B161,493 polarization close to 100%. The momentum spread, (1979). Ap/p, is «2%. An electrostatic deflector removes the electrons and provides a muon beam of high purity 10. P. Herczeg, Proc. of the Workshop on Program Options in Intermediate-Energy Physics, Los Alamos Scientific Laboratory that is deflected out of the aperture of the apparatus report LA-8335-C (May 1980). whenever a muon enters the apparatus; •a time projection chamber (TPC) for determining the 11. S. M. Berman and D. A. Geffan, Nuovo Cimento 18, 1192 momentum and emission angle of the positrons from (1960). the n's that decay within the fiducial volume of the chamber. The chamber operates in a magnetic field 12. C. Quigg and J. D. Jackson, Lawrence Radiation Laboratory of high uniformity, «0.2%, and gives the (x,y,z) report UCRL-18487 (1978), unpublished. coordinates of many points along the helical positron trajectory; 13. J. Fischer, P. Extermann, O. Guisan, R. Mermod, B. Morel, L. Rosselet, R. Sachot, P. Block, G. Bunce, B. Devaux, A. M. • a readout that uses eight-bit "flash" encoders to give Diamant-Berger, N. Do-Due, G. Marei, and R. Turlay, Phys. precise time and amplitude measurements of the Lett. 73B, 364 (1978). "pad" pulses. The flash encoder measures the shape of the pad pulse by sampling its amplitude every 40 ns. This allows for a precise time measurement of High-Precision Study of the u+ Decay Spectrum the centroid and a measurement of the total charge (Exp. 455, P3) in the pulse to be compared with pulses from neighboring pads to determine position (see Fig. 1); (Los Alamos, Univ. of Chicago, National Research and Council in Canada, Carleton Univ.) Spokesmen: H. L. Anderson (Los Alamos) and W. W. • a system geared for high statistics. The event rate is 6 8 Kinnison (Univ. of Chicago) 100/s for 10 s for a total of 10 events in each of several runs planned. The object of this experiment is to establish a more Most of the features outlined above were operational precise knowledge of the constaints of the weak interac in the last 6 months of 1981. We also accomplished the tion. It will test with five times greater sensitivity whether following. V-A correctly describes the weak interaction in am • The magnetic field was explored with nuclear- plitude and phase, as current dogma asserts. The experi magnetic-resonance (NMR) probes and trimmed Fig. 1. Pulse heights from neighboring pads, indicating how a precise position may be obtained by inter polation. July-December 1981 PROORESSATLAMPF 53 Los Alamos National Laboratory with auxiliary coils to produce the desired uni and found AR/R = 0.037, in agreement with theory, formity over a large fraction of the fiducial volume. and Ap/p = 2%. •The muon beam was tuned during a 1-week test run •In our third test run in November we read out the in July and gave a satisfactory rate within a 2-cm- pad signals with 173 flash encoder readouts. This diam spot with a momentum spread Ap/p ~ 2%. allowed full reconstruction of events. Our software •In a second test run in September we mounted one programs allowed us to do reconstruction on line of our TPC modules m the magnet and in the beam and we obtained several thousand events. We show and were able to display the stopping u's within the an example in Figs. 2(a)-(d). chamber by drift-time measurements. We could •We obtained several thousand events with a graphite change the location along the axis of the chamber target placed at the entrance opening of the TPC. where the j/s stopped by adding or subtracting a These are being analyzed offline to obtain a Michel moderator. We measured range and range straggling spectrum in the region defined by our trigger. This Figs. 2(a)-(d). (a) The (\,y) view of an event with momentum 22.7 MeV/c, emission angle 6 = CR~Y-0.°79J. (b) The (yj.) view of the event. (c) The (\,z) view of the event. (d) Three-dimensional view of the event. 54 PROGRESS AT LAMPF July-December 1981 Los Aiamos National Laboratory will be a first measurement of the asymmetry The exclusive DCX reaction, in which the residual because the trigger concentrated on forward-emitted nucleus is left in a discrete final state, has been studied in positrons, for which the asymmetry is greatest. several recent experiments. Various puzzles remain, for The next step is to install all the modules for the final example, in the diffraction-like structure seen in the spectrometer. We expect to have this ready for an an angular distributions and in the relative magnitudes of ticipated extended run at LAMPF starting in June/July. double-isobaric-analog and nonanalog transitions. The The full data-acquisition rate will depend on completion unexpectedly large cross sections for the latter, which of the preprocessor unit of the system, which we hope were observed in the first experiments on 160 and lsO, can be ready for use for the summer run. have led to the realization that not only the configura tions of the initial and final nuclear states but also the spectrum of intermediate states play important roles in A Measurement of Inclusive Pion Double Charge the description of this process.5,6 In the inclusive DCX Exchange on 160 and 40Ca reaction, by comparison, nuclear structure enters in the (Exp. 309, P3) configuration of the initial state, the question of inter (Univ. of Wyoming, Massachusetts Institute of mediate states merges into a description of the propaga Technology, Los Alamos, Univ. of New Mexico) tion of rc^s or A's in nuclear matter, and the final state Spokesman: G. A. Rebka (Univ. of Wyoming) must be properly antisymmetrized (that is, "Pauli block ing" will be important). The pion double charge exchange (DCX) reaction — Previous data on inclusive DCX reactions are both in which a charged pion interacts with a nucleus and a sparse and contradictory. Large discrepancies exist pion of opposite charge emerges — has been a topic of among calculations,2'7,8 as well as among active investigation at LAMPF and other laboratories. measurements9,10 of the "Hefa^Tt*) cross sections. A Because charge conservation forbids DCX in a single more recent investigation of the *He(n+,n~~)4p process10 pion-nucleon interaction, the process necessarily involves yielded results greatly exceeding those of a prediction8 successive scatterings from at least two nucleons (or, based on sequential single-charge-exchange scatterings, possibly, from the pion field of the nucleus).1'2 In this leading the authors10 to deduce the dominance in this respect, the DCX mechanism is the complement of true process of scattering from mesonic-exchange currents. A pion absorption which, because of energy-momentum recent measurement4 completed at SIN of the 160(ji+,7t") conservation, occurs predominantly on two nucleons, cross section at Tn+ = 240 MeV was found to disagree and which is an important competing channel in pion- markedly with earlier results obtained using nuclear nucleus reactions. It is natural to hope that DCX (for ex emulsions.11 The observed pion energy spectrum and ample, n+nn —»• n0pn -* n'pp) might contain informa angular distribution showed little resemblance to the tion on AW correlations in the nucleus and on the nature shape expected from four-body phase space. Clearly of multiple-scattering mechanisms. Because of the something interesting is occurring in this reaction, but no strength of the free n-N interaction these mechanisms are theoretical calculations have as yet been performed. expected to dominate it-nucleus reactions as they do N- In the present experiment we have undertaken a nucleus reactions, yet present multiple-scattering theories systematic investigation of the inclusive DCX process in do not directly account for absorption,3 and quasi-free complex nuclei with good statistical accuracy over a pion-scattering measurements exhibit a pronounced broad range of incident pion energies and outgoing pion single-scattering character.4 For incident pions of kinetic angles. It is hoped that the resulting data set will provide energy ~160 MeV it is expected that excitation of the motivation for further theoretical study and thus lead to A(1232) resonance in an intermediate state (for example, a better understanding of the DCX reaction mechanism + n+nn _* A « —*• A°p —»• n~pp) will play a significant role in both inclusive and exclusive processes. in the DCX mechanism. A theoretical calculation using The work reported here has concentrated on measure the A-hole model for n-nuclear interactions, which will ments of the 160(7I±,JI:,:) and 40Ca(it±,ji:F) cross sections; yield predictions for DCX together with pion scattering some exploratory results were also obtained for 12C and and nucleon knockout (n,nN) cross sections, is currently 208Pb. Data were taken for incident pion energies be being formulated. tween 120 and 270 MeV and for outgoing pion energies between 10 MeV and the four-body phase-space cutoff *T. Karapiperis and E. J. Moniz, private communication, 1981. (~30 MeV below the kinematic limit) at angles between July-December 1981 PROGRESS AT LAMPF 55 Los Alamos National Laboratory 25 and 130°. The accuracy is everywhere better than background problems. Low background rates were es ~10%, limited mainly by counting statistics. Auxiliary sential to the success of this measurement of cross sec measurements of the differential cross section for Ttr-p tions as low as 0.01 ub/MeV-sr. Backgrounds were elastic scattering were performed at each incident energy further reduced by demanding a coincidence between the to obtain an absolute normalization of the DCX cross midplane MWPC and the focal-plane chambers and sections. scintillator in the event trigger, thus ensuring that the The experiment was performed in the P3-East channel detected particle came through the spectrometer. using the 325-MeV/c, 180° double-focusing spec Electrons (or positrons) resulting from conversion of trometer (Fig. I). The spectrometer was equipped with a decay photons from n°'s produced in (n±,n0') reactions in multiwire proportional counter (MWPC) between the the target were separated from pions in the analysis by two 90° dipoles and a focal-plane detector consisting of examining the pulse height in the Cerenkov counter for two MWPCs, a plastic scintillator, and a fluorocarbon each event. Electrons always produced a large pulse; Cerenkov counter. This spectrometer is well suited for in pions of energy <90 MeV produced either no light or a clusive DCX measurements; because the flight path pulse of sufficiently smaller amplitude so that the separa from target to focal plane is only 3.5 m, one can observe tion was unambiguous. For higher energies the pion and pions with energies as low as 10 MeV and can correct electron distributions began to overlap, but a peak-fitting reliably for pion decay. The double-focusing property procedure still allowed adequate separation. In the keeps the focal plane small while maintaining a relatively (7t~,Tt+) measurements a copious proton yield was ob large momentum acceptance (Ap/p = 9%) and solid served, together with smaller numbers of deuterons and angle (Aft=I5msr), thus reducing shielding and tritons. These were cleanly separated from the pions by examining either the scintillator pulse height or the flight time between the midplane and focal-plane chambers. A TARGET, SPECTROMETER a DETECTOR stringent cut on the particle trajectories through the two ASSEMBLY focal-plane chambers allowed the elimination of most of the muons; the remaining contamination will be assessed with the aid of a Monte Carlo calculation. ,2 40 208 Solid C, CH2, Ca, and Pb targets of thickness 0.5-1 g/cm2 were used. For the I60 measurements the 2 target was 1.1 g/cm of H20 contained in an aluminum frame with 0.05-mm Mylar windows. The n-p scattering I2 data were obtained from a (CH2- C) subtraction. For the DCX runs, backgrounds were measured with an empty target frame and with an empty H20 container, and were found to be <2%. The incident pion beam was monitored both by an ion chamber placed immediately following the last quadrupole in the P3-East channel and a scattered- MYLAR - particle telescope that observed, at 90° to each side of WINDOW the beam, an auxiliary 3-mm-thick CH2 target located 3 m downstream from the scattering chamber. A profile TARGET LADDER monitor just upstream of the scattering chamber 90° BENDING MAGNET measured the steering and focusing of the beam. Inter- SLITS ..VACUUM comparison among these monitors provided a con PUMP tinuous check of beam steering and ion-chamber gain. l6 40 VERTICAL Preliminary analysis of the 0 and Ca DCX results ROTATION AXIS has yielded pion spectra of which typical examples are shown in Fig. 2. The absolute normalization of these Fig. 1. cross sections was determined from a comparison with The 325-MeV/c double-focusing spectrometer. the auxiliary n-p scattering results obtained using iden tical apparatus and analysis procedures. The present 56 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 10.0 1 T" 4. R. E. Mischke, A. Blomberg, P. A. M. Gram, J. Jansen, J. Zichy, ,60(7r+.-!r-) • J. Bolger, E. Boschitz, C. H. Q. Ingram, and G. Probstle, Phys. Rev. Lett. 44, 1197 (1980). TT in-240 MeV • 8«25» 5.0 • • • A 9 = 130° 5. M. Cooper, Proc. of LAMPF Workshop on Pion Single Charge Exchange, Los Alamos Scientific Laboratory report LA-7892-C (1979), p. 194. 6. T. Marks, M. P. Baker, R. L. Burman, M. D. Cooper, R. H. Heffner, R. J. Holt, D. M. Lee, D. J. Malbrough, B. M. Preedom, >i R. P. Redwine, J. E. Spencer, and B. Zeidman, Phys. Rev. Lett. « 38, 149 (1977); R. J. Holt, B. Zeidman, T. Marks, D. J. Malbrough, B. M. Preedom, M. P. Baker, R. L. Burman, M. D. .o I Cooper, R. H. Hefiher, D. M. Lee, R. P. Redwine, and J. E. 3-..0 Spencer, Phys. Lett. 69B, 55 (1977); C. Perrin, J.-P. Albanese, R. UJ Corfu, J.-P. Egger, P. Gretillat, C. Lunke, J. Piffaretti, E. •o CJ Schwarz, J. Jansen, and B. M. Preedom, Phys. Lett. 69B, 301 (1977); R. L. Burman, M. P. Baker, M. D. Cooper, R. H. b Heffner, D. M. Lee, R. P. Redwine, J. E. Spencer, T. Marks, D. J. % 0.5 Malbrough, B. M. Preedom, R. J. Holt, and B. Zeidman, Phys. Rev. C17, 1774 (1978); and K. K. Seth, S. lversen, H. Nann, M. Kaletka, J. Hird, and H. A. Thiessen, Phys. Rev. Lett. 43, 1574 (1979). 7. F. Becker and C. Schmit, Nucl. Phys. BI8, 607 (1970). 8. W. R. Gibbs, B. F. Gibson, A. T. Hess, and G. T. Stephenson, Jr., Phys. Rev. C15, 1384 (1977). 0.1 40 80 120 160 9. L. Gilly, M. Jean, R. Meunier, M. Spighel, J. P. Stroot, and P. .-MeV Duteil, Phys. Lett. 19, 335 (1965); L. Kaufman, V. Perez- Mendez, and J. Sperinde, Phys. Rev. 175, 1358 (1968); I. V. Falomkin, M. M. Kulyukin, V. I. Lyashenko, G. B. Pontecorvo, Fig. 2. Yu. A. Shcherbakov, C. Georgescu, A. Mihul, F. Nichitiu, A. The doubly differential cross section for the reac Sararu, and G. Piragino, Nuovo Cimento 22, 333 (1974); and I. ls + tion O(n ,K~)for T„ in = 240 MeV compared at V. Falomkin, V. I. Lyashenko, G. B. Pontecorvo, Yu. Shcher 0 _ = 25 and J30°. Where errors are indicated bakov, M. Albu, T. Angelescu, O. Balea, A. Mihul, F. Nichitiu, they are statistical; where not shown they are A. Sararu, F. Balestra, R. Garfagnini, G. Piragino, C. Guaraldo, aiki R. Scrimaglio, Lett. Nuovo Cimento 16, 525 (1976). smaller than the plotted symbols. 10. A. Stetz, L. W. Swenson, J. Davis, J. Kallne, R. C. Minehart, R. R. Whitney, V. Perez-Mendez, A. Sagle, J. Carroll, J. B. 16 data for 0(7i+,7T) at TK m = 240 MeV are found to be in McClelland, and J. Faucett, Phys. Rev. Lett. 47, 782 (1981). good agreement with previous SIN results.4 11. Yu. A. Batusov, S. A. Bunyatov, V. M. Sidorov, and V. A. REFERENCES Yarba, Yad. Fiz. 3, 309 (1966) [Sov. J. Nucl. Phys. 3, 223 (1966)1; Yu- A- Batusov, S. A. Bunyatov, V. M. Sidorov, V. A. Yarba, G. Ionice, E. Losnianu, and V. Mihul, Yad. Fiz. 5, 354 1. W. B. Kaufmann, J. C. Jackson, and W. R. Gibbs, Phys. Rev. (1967) [Sov. J. Nucl. Phys. S, 249 (1967)]; Yu. A. Batusov, S. A. C9, 1340 (1974). Bunyatov, V. M. Sidolrov, and V. A. Yarba, Yad. Fiz. 6, 998 (1967) [Sov. J. Nucl. Phys. 6, 727 (1968)]; and Yu. A. Batusov, 2. J. F. Germond and C. Wilkin, Nuovo Cimento Lett. 13, 605 S. A. Bunyatov, N. Dalkhazhav, G. Ionice, E. Losneanu, V. (1975). Mihul, V. M. Sidorov, D. Tuvdendorzh, and V. A. Yarba, Yad. Fiz. 9, 378 (1969) [Sov. J. Nucl. Phys. 9, 221 (1969)]. 3. R. M. Thaler, Proc. July-December 1981 PROGRESS AT LAMPF 57 Los Alamos National Laboratory Preliminary Report on a New Pion-Beta Decay Ex- 400-MeV rt+ beam in the P3-East channel. The massive perimtui TC° from the n+ beta decay has essentially the same + (Exp. 32, P3) momentum as the 7i , and we detect the two energetic (Temple Univ., Los Alamos) y rays from the n° decay. It is necessary to use a very in 8 + Spokesman: R. J. Macek (Los Alamos) tense beam of 2 X 10 rc /s. Figure 1 shows, our ap paratus. The conserved-vector-current (CVC) hypothesis,1 a To avoid background from pion charge exchange the 7 cornerstone of the unified theory of electromagnets and decays take place in a vacuum tank at 2 X 10" torr. weak interactions, provides a precise prediction for the There is an intense flux of secondary u's from the decay branching ratio of the pion-beta decay reaction u+ —*• of the it's. The beam is collimated and the detectors 7t°e+v. The predicted ratio is 1.045 X 10~8 with an uncer located so that they cannot see these u's. The last tainty of 0.5% due to errors in the pion masses and an collimator is toroidally magnetized iron to reduce u scat additional 1% uncertainty due to the electromagnetic tering out of the collimator. This magnetization of the corrections. The most precise existing experiment is that collimator allowed us to run at a beam rate 3 times of Depommier et al.,*'2 who found a branching ratio of more intense than would otherwise have been tolerable. IJOOSS x i Left side gamma detector Beam-defining Magnetic collimator collimator To beam- monitoring devices =t"~ Vacuum tank and decay region Gamma-ray converter array Total absorption energy-measuring lead-glass array 1 m Fig. 1. Layout of pion-beta-decay apparatus. 58 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 180 REFERENCES 1. R. Feynman and M. Gell-Mann, Phys. Rev. 109, 193 (1958). 2. D. Depommier, J. Duclos, J. Heintze, K. Kleinknecht, H. Rieseberg, and V. Soergel, Nucl. Phys. B4, 189 (1968). Crystal Box Experiment (Exps. 400/445, SMC) (Los Alamos, Stanford Univ., Univ. of Chicago) Spokesmen: C. M. Hoffman, J. D. Bowman, and H. S. Matis (Los Alamos) This experiment and some aspects of the data- acquisition system have been described in the preceding three progress reports. Briefly, this experiment aims to search with unprecedented sensitivity for the lepton- flavor violating decays u+ —> e+e+e~, u+ —>• ey, and u+ —»• e+vy. The detector consists of a modular array of 0 100 200 300 400 500 600 700 TOTAL GAMMA-RAY ENERGY, MeV 396 NalfJY) crystals, a precision cylindrical drift cham ber, and an array of plastic scintillation counters. A Fig. 2. schematic view of the apparatus is shown ii\ Fig. 1. Distribution of the sum of the energies of coinci The goal for this experiment is to be sensitive to the dent pairs of gamma rays. three rare-decay modes with branching ratios smaller than 10-n. To achieve this goal in a reasonable amount of running time (-~106 s) one must have a copious source variables show distinct peaks as expected for beta decay. These variables provide additional cuts, but it is not 10 CRYSTALS DEEP necessary to make any but very mild cuts to further 9 CRYSTALS ACROSS DRIFT CHAMBER clean up the event selection. 8 PLANES, The events shown in Fig. 2 represent very nearly our final sample. A later analysis gave a total of 1127 ± 33 events after background subtraction. Including uncer tainties in the incident pion fiux, detection efficiency, and various other corrections, we quote a preliminary result of (1.05 ± 0.06) X 10"8 for the branching ratio. Presently, we are analyzing the beam monitor data (we had several different monitors), including phase- space data. We are hopeful that this will not be a major contributor to the final accuracy, but we have learned that long-term monitoring of high-intensity pion beams at the 1% level is a significant technical problem. We expect to improve our estimates of uncertainties and to be able to produce a number with a quoted error determined mainly by the statistics (that is, at about the 4% level), and thus to have a significantly better value -36 HODOSCOPE COUNTERS for the branching ratio of pion-beta decay, although still not with a precision approaching that of the theory. Fig. J- Schematic view of the Crystal Box. July-December 1981 PROGRESS AT LAMPF 59 Los Alamos National Laboratory TABLE I CRYSTAL BOX RESOLUTIONS System Quantity Achieved Resolution Nal EgEy AEIE = 0.058 (FWHM), 50 MeV AT 0.4 ns (FWHM) A* <3.5 cm (FWHM) Scintillator At 0.35 ns (FWHM) Drift chamber Ax £150 urn (rms) of muons and a large acceptance for the events of in end plates within tolerances. We expect delivery of the terest, and one must be able to eliminate background end plates early in 1982, and the stringing of the cham processes to at least the expected level of sensitivity. We ber will begin shortly thereafter. We expect the chamber plan to stop 5 X 10s u+/s in the center of the detector. and all its electronics to be ready by the summer of 1982. This rate, together with the acceptance of the apparatus A major test run occurred in November 1981 at the (~25-50% depending on the mode), gives the desired sen SMC to test the electronics, the data-acquisition system, sitivity. The major source of backgrounds is the chance the on-line software, and the scintillator array. In almost coincidence of e+,s and y's from the uncorrected decays all respects this run was extremely successful. It of several muons. These backgrounds are eliminated by demonstrated that these major components of the experi requiring the detected particles to be in time coincidence ment perform as expeaed. The stend that will be used to and by imposing conservation of energy and momentum; support the apparatus was assembled and used for this good background rejection depends on good resolutions test In addition, 100 channels of constant-fraction dis in timing, position, and energy. criminators, 40 channels of mean timers, the nonad- We have performed extensive tests with prototypes of jacency and geometry boxes, several logic fan-out each part of the detector. The achieved resolutions are modules, and a CAMAC latch were all constructed for shown in Table I. These resolutions are more than ade this run. However, the need for some minor modifica quate to reject backgrounds to the desired levels. tions in the output-pulse generation by the constant- A test ran in August 1981 at the SMC was used to fraction discriminators and the mean timers was un define the final parameters for the electronics for the drift covered. In all other respects all these modules operated chamber, and an LRS-4290 system was successfully successfully. More importantly, the basic philosophy used to read out a test chamber. The preamplifiers and that went into designing the trigger electronics proved to amplifier discriminators, which supply signals to the be correct. The propagation delay through all the elec time-digitization system, also performed up to expecta tronics was measured so that delay cables for all the tions. The only major change in the electronics was to signals can be constructed. The time resolution of the reduce the bandwidth of the preamplifiers somewhat to scintillation counters and the electronics was within minimize the crosstalk between adjacent drift-chamber specifications. cells. The performance of the electronics and the cham We were not able to use the PDP-11/44 computer, ber was satisfactory. We demonstrated the ability of the which was purchased for this experiment, because of chamber and the read-out system to operate at beam problems between the computer and the micropro rates higher than we expect for the experiment. grammed branch driver. These problems are being The NuCon Company of Livonia, Michigan is worked on by Group MP-1. Instead, a PDP-11/45 com manufacturing the end plates for the drift chamber. After puter was usee', for this run. Generally speaking, the data- a painstaking upgrading of their five-axis machine they acquisition software worked well, though several bugs have demonstrated that they can successfully make the were uncovered and the need for some additional 60 mOQREttATUkMPF July-December 1981 Lot Alamos National Laboratory features was demonstrated. The large-scale-integrated- The primary motivation for these studies is the need (LSI) circuit system to read out the Nal information also for determination of the mean-square radius difference 2 worked quite well. The pulse-height modules and the tim § 241 243 tageous for oAd-A nuclei with large quadrupole moments Muonic X-Ray Study of Am and Am because the M x-ray energies are insensitive to assump (Exp. 653, SMC) tions concerning the nuclear charge distributions, having (Los Alamos, Oak Ridge, Princeton Univ., Purdue only the hyperfine interaction as a major contribution to Univ.) the observed splittings. (Dynamical mixing of nuclear Spokesmen: E. B. Shera and M. W. Johnson (Los states also contributes, but at a much lower level.) The Alamos) and R. A. Naumann (Princeton Univ.) results given in Table I are in excellent agreement with results of a recent 243Am(a,a') study,2 but the ratio This experiment has as its objective the determination e0(241)/eo(243) = 1.035 ± 0.010 is somewhat larger 3 of the nuclear charge distributions of "'Am and " Am, than that suggested by optical-spectroscopic the heaviest nuclei ever studied with muonic-atom tech measurements.3 niques. Data acquisition was completed during a 20-shift The situation with the TABLE I PROPERTIES OF "'Am AND "3Am DEDUCED FOR MUONIC X-RAY DATA Nuclide Qfcb) B(E2; 5/2 — 7/2)(e2b2) c(F)' "'Am 4.420 ± 0.030 7.243 ± 0.087 7.061; + 0.0004 34.72507 "3Am 4.272 ± 0.028 6.482 ± 0.079 7.0815 ±0.0004 34.86609 aThe a is fixed at 0.552 F. July-December 1981 PROGRESS AT LAMPF 61 Los Alamos National Laboratory P(?) = P from muonic-atom data, it is necessary that good data 3. T. E. Manning etal., Phys. Rev. 102, 1108 (1956). exist for both K and L muonic x rays. Unfortunately, this condition is not satisfied in the present case. The HFS in the L lines is so extreme that little information can be extracted from them. Consequently, it has been assumed Inelastic Pion Scattering by 170, 180, and ,9F that both isotopes are adequately described by a skin (Exp. 369, EPICS) thickness a = 0.522 F. With this constraint, values for c (Univ. of Minnesota, Los Alamos) 2 2 and 1 1 i i - IOOO - n + 164-MeV 7T (11 ^f Fig.l. Spectrum for 164-MeV 7r+ scattering from oxygen at 42" 62 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory l2H Elastic Scattering of Pions from C at 164 MeV ter. For the first part of Exp. 539, movement of the spec in 1° Bins trometer off center caused the true scattering angle to (Exps. 539/622, EPICS) decrease ~0.05° every 10°. (Univ. of Texas, Univ. of Minnesota, Los Alamos, New A preliminary analysis of elastic scattering on 14C Mexico State Univ.) from the first part of Exp. 539 is presented in Figs. 1 and Spokesmen: H. Baer (Los Alamos) and D. Holtkamp 2. Figure 3 displays fits to these data using PIESDEX, a (Univ. of Minnesota) code developed by E. Siciliano and M. Johnson. Figure 4 shows the final 7t+ cross sections for the 12C strip target In analyzing the elastic-scattering data from Exps. data, which were taken simultaneously with the 14C data. 539/622 [14C(ji,7tO,4C; I2C(jt,7t012C at 164 MeV], a The slope of the 1 ° bins in the 12C data is correct to great amount of effort has been spent in obtaining the within error bars. To obtain a smooth angular distribu angular distributions in 1 ° bins instead of the usual full tion for the 1 ° binned data, it was necessary to normalize acceptance (~4°) of the EPICS spectrometer, because the experimental yields every 10° using hydrogen runs. such data are particularly useful in outlining minima. It At the 5° midpoints between normalization runs, nor was determined in the analysis that the 1 ° bins of EPICS malizations had to be averaged. Severe (10-20%) were well calibrated and centered correctly. On that problems existed in the slope of the 1 ° data when dif basis a kinematic analysis using the 1° capability of ferent normalizations were not used every 10°. The EPICS provides a reliable angle calibration of the ex relative solid angles of the 1 ° bins were found to be a perimental data, that is, it reveals any effect caused by strong function of angle. the angular divergence of the beam on the target and shows whether or not the spectrometer is moving off cen 100f I I I I I I I I I I I I I I I I 1 I I , 100 I I I I I I I I I I I I I I I i •14C ELASTIC TT 14 , C ELASTIC n* 164 MeV 164 MeV 10 10 V} E *••% IiIf 0.100 0.100 I 0.010. t i i i i i t i i i i i • t • i i i • I 0.010' '»«•«« i t • i i • • i • • • • • 35 40 45 50 55 60 65 70 75 80 85 35 40 45 50 55 60 65 70 75 80 85 cm. ANGLE (deg) cm. ANGLE (deg) Fig. 1. Fig. 2. Elastic cross sections for jt+ incident at 164 MeV Elastic cross sections for n~ incident at 164 MeV on "C. on 14C. July-December 1981 PROGRESS AT LAMPF 63 Los Alamos National Laboratory 1001 I I I I I I I I | I I I I I I I I I I N — Z Dependence of Analog Double-Charge- Exchange Reactions ... 14C ELASTIC FIT (Exp. 606, EPICS) n", 164 MeV (Northwestern Univ.) 1«C ELASTIC FIT Spokesman: K. K. Seth (Northwestern Univ.) n+, 164 MeV We have successfully completed measurements of the first clear-cut double-analog transition to a highly excited state in the continuum. The reactions 48Ca(T£+,n")48Ti and 48Ti(7i+,;r)48Cr were studied at 9 = 5° and E(n+) = 130, 180, 235, and 290 MeV. The double-analog transi tions in both reactions were clearly observed. The one in 48Ti occurs to a T=4, Jn = 0+ state at 17.379 MeV, which had been earlier identified by Sherr and colleagues1 in a S0Ti(p,t)*>Ti experiment. It is interesting to note that the transition is seen even more clearly in our double-charge-exchange (DCX) experiment, as is il lustrated in Fig. 1, which shows the 180-MeV spectra. 35 40 45 50 55 60 65 70 75 60 65 The double-analog transition to the 8.75-MeV state in 48 cm. ANGLE (deg) Cr is> seen equally clearly. The experiment on 48Ca was done to determine how Fig. 3. + l4 analog DCX cross sections increase with (N — Z). All The Jt and it" elastic cross-section Jits for C us first-order theories2 predict an increase oc(N - Z)(N - Z ing PIESDEX. — 1) due to an increase in neutron pairs, and a decrease ccA~x, (with x between 3 and 4) due to absorption. This would predict, for example, a ratio 100 I I I I 1 I I I I I I I I I 1 I I I 12 + C ELASTIC n 0 48 42 164 MeV o(5 , Ca)/o(5°, Ca) x 20 25 48Ca(irV-^8Ti(T-4J > 20 174 MeV (T«4) o E o S! 15 "5" (A H X Z 3 to X \ 0.100 „.AJW^ M 16 18 20 22 24 26 EXCITATION IN 48Ti (MeV) 0.010' ' ' ' I I I I I t i i i i i i i i t i Fig.l. 35 40 45 50 55 60 65 70 75 60 85 Excitation of the 0+,T-4 state at 17.379 MeV in cm. ANGLE (deg) the 48Ca(Tt+,7T)48Ti reaction at E(it+) = 180 MeV. Fig. 4. Elastic cross sections for TC+ incident at 164 MeV on nC. 64 PROGRESS AT LAMPF Juty-Dacember 1981 Los Alamos National Laboratory An earlier exploratory investigation3 by us had indicated that this ratio is strongly quenched, perhaps by^s much C(ir,ir ) as an order of magnitude. On-line analysis of the present q = 285 MeV/c experiment indicates that this is true. The measured ratio is ~3. Earlier, we suggested,3 on the basis of the preliminary experiment, that this quenching might arise because of an interfering contribution from an isotensor term in the EI a pion-nucleus optical potential. The suggestion should be bicj considered seriously now in view of the clear results of the present experiment. • 11.67MeV v" REFERENCES o 15.2 MeV ir* • l7 26MeVT* a sin's/10 1. R. T. Kouzes, P. Kutt, D. Mueller, and R. Sherr, Nucl. Phys. A309, 529 (1978). 2. G. A. Miller and J. E. Spencer, Ann. Phys. N.Y. 100, 562 (1976); 120 140 160 180 200 220 240 K. K. Seth, Proc. LAMPF Workshop on Pion Single Charge Ex Er(MeV) change, Los Alamos Scientific Laboratory report LA-7892-C (1979), pp. 201-221; M. B.Johnson, Phys. Rev. C22, 192 (1980). Fig. 1. Excitation functions for three levels proposed as 3. K. K. Seth et al.. Bull. Am. Phys. Soc. 25, 725 (1980). (4~, T = 1) states. The solid line is a curve propor tional to sin2 8. Investigation of the Strong Cancellations of Neutron/Proton Transition Amplitudes in 14C 10 (Exp. 622, EPICS) E~l—i—l—i—'—1—I—I—l—I—T l4 + + (Univ. of Minnesota, Los Alamos) 164-MeV C(7T ,7r ') Spokesman: D. Holtkamp (Univ. of Minnesota) 17.26-MeV (4,"I) 1 Experiment 622 has been completed. Excitation func I0 tions for n* scattering at two momentum transfers, as well as a limited angular distribution for it1 scattering at 120 MeV, were measured. Three candidates for 4" states (T= 1) in ,4C are iden blcs iff1 tified at 11.67, 15.2, and 17.26 MeV. Excitation func tions for these states are shown in Fig. 1, together with a curve proportional to sin2 6. These peak cross sections taken at a momentum transfer of ~286 MeV/c indicate I02k that these transitions follow the trend of a sin2 6 curve. This behavior, together with the measured angular dis tribution shapes, is the basis for the tentative 4~ assign ment. The angular distribution for the 17.26-MeV state 10f 3 J I I I I I at 164 MeV is shown in Fig. 2. Preliminary distorted- 20 40 60 80 100 120 wave-impulse-approximation (DWIA) calculations cm. ANGLE (deg) l assuming a pure (ds/2,p3/i \- configuration are shown with the data and are seen to give a good fit (normaliza Fig. 2. + tion of the calculation is arbitrary). In addition, these Angular distribution for Jt inelastic scattering at states exhibit the same angle and energy dependences as 164 MeV to the 17.26-MeV level, together with known A/4 transitions .in 12C, l3C, and 160. preliminary DWIA calculations (solid line). July-December 1981 PROGRESS AT LAMPF 65 Los Alamos National Laboratory Nonanalog Double Charge Exchange (Exp. 577, EPICS) (New Mexico State Univ., Univ. of Penn., Univ. of Texas, Los Alamos) Spokesmen: S. J. Greene (New Mexico State Univ.) and H. T. Fortune (Univ. of Pennsylvania) The fact that nonanalog pion double-charge-exchange (DCX) cross sections can be as large as those for analog DCX is a surprise. A recent EPICS experiment was devoted to studying this point. A 164-MeV angular dis tribution was measured for the reaction 160(jt+,7r)16Ne ground state (g.s.). Also measured were the (K+,IC) ground-state transitions from targets of ^Si and 40Ca at a laboratory angle of 5° and bombarding energy of 164 MeV. MASS NUMBER (A) Figure 1 shows the 16Ne (g.s.) angular distribution and contrasts it with the 164-MeV l8Ne(g.s.) distribution Fig. 2. resulting from analog DCX1 on I80. The I8Ne angular A dependence of nonanalog DCX ground-state distribution is not simple diffractive, having a minimum transitions from T = 0 targets, at Tn = 164 and near 21°, corresponding to a nuclear radius of ~5.7F, 180 MeV. which is unphysically large. The first minimum of the 16Ne distribution is about 32°, appearing to be diffractive m 18 in nature, an angle corresponding to a nuclear radius of • 0(7r*t7r> Ne(DIAS) -3.3 F. Ols0(7r+,7T-),S Ne(g.s.) In Fig. 2 we show the new A dependence data and in i.o- * Tw * 164 MeV clude previous1 180-MeV data. Both sets appear to be reasonably described as following an A ~~*n mass depen dence. The 180-MeV set may be normalized to the 164- M MeV set by using I6Ne, which was measured at both energies, and by the observation that all nonanalog tran 5-oi- sitions exhibit the same energy dependence in this region. The combined set indicates A~AI}, with some variations that may be traceable to nuclear structure shell level ef b fe fects. •a U\ The mixing element for a A component in the ground- 0.01- state wave function of J= 2 nuclei varies as A ~*. We have proposed the mechanism shown in Fig. 3, a single- step DCX reaction resulting in formation of a A++, as a way of explaining the A~m dependence. The A'1 am plitude gives an overall A'1 in cross section, which then multiplies a fundamental cross section of RlvzAm. o.ool The reaction amplitude, in the Eikonal model, varies B 2 as Fig. 1. The !60(7t+,7t-)l6Ne (g.s.) and 180(jr+,jO18Ne dou J(n+n ->- TI~A++) ble isobaric analog state (DIAS) angular distribu ftk.q) = $kRa + + JB(qR) tions at T„ = 164 MeV. f[n N ->- n N) 66 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory The Study of Broad-Range Pion Inelastic-Scattering / 7T \ / Spectra (with Emphasis on the Excitation of the \ / \ / Giant Monopole Resonance) \ K+ + (Exp. 597, EPICS) n. -P (Univ. of Washington, Carnegie-Mellon Univ., Los n. •P Alamos) Spokesman: I, Halpern (Univ. of Washington) Fig. 3. Few reliable data exist at forward angles on cross sec Single-step DCX leading to the formation of a tions and spectra for pion inelastic scattering to high ex A++. citation, in part because of large backgrounds of decay muons in the pion beam. Another problem at forward angles is the copious rescattering of small-angle where elastically scattered pions inside the spectrometer. The forward angles are particularly interesting because here it should be possible with pions to excite E0 and El giant PROGRESS AT LAMPF 67 July-December 19B1 Los Alamos National Laboratory Nuclear Chemistry dicular to the beam direction, whereas in those designed to yield the perpendicular ranges it was mounted at 10° I2 ± n to the beam. A Product Recoil Study of the C(n ,nJV) C n Reactions over die Energy Range 90 to 350 MeV Following irradiation, the C activity in the target and (Exp, 543, LEP and P3) catcher foils was assayed with a y-v coincidence counter consisting of two NaI(T<) scintillation detectors mount (Carnegie-Mellon Univ., Purdue Univ., Los Alamos) ed on opposite sides of the target foil. The efficiency- Spokesman: A. A. Caretto (Carnegie-Mellon Univ.) calibrated system was set to count the 511-keV quanta resulting from annihilation of the 20.4-min nC positrons. Conceptually there are two major mechanisms by The disintegration rates of the various foils were used which a pion- (or proton-) induced nucleon-removal to obtain the average projected ranges of nC in carton, reaction might take place: designated FW, BW, and PW. The quantities F, B, and P (1) director knockout (DKO), whereby the incident are the fraction of the total number of nC nuclei recoil pion strikes a bound nucleon, causing its ejection. ing into the forward, backward, and perpendicular The incident particle and the struck nucleon exit catchers, respectively, and W is the surface thickness of the nucleus without further interaction, leaving a the target. In the case of the 10-degree runs, the value of residual nuclear excitation energy of less than P represents the average of the results obtained for the about 10 MeV to preclude subsequent nucleon two catchers. evaporation; and The energy dependence of the projected ranges is dis (2) inelastic scattering followed by evaporation (ISE), played in Fig. 1. We see that the projected forward whereby the incident pion inelastically scatters off ranges decrease with increasing pion energy, the project a bound nucleon, transferring between 10 and 20 ed perpendicular ranges are largely independent of MeV to that nucleon. The nucleon subsequently energy, and the projected backward ranges increase with evaporates, which deexcites the nucleus and bombarding energy. Furthermore, the energy depen produces the nucleon-removal product. dence of FW and B W is markedly stronger for incident Mechanism (1) would predict a relatively isotopic iC than for 7t+. angular distribution for the recoiling UC nuclei in 2 ± Our results constitute the first determination of recoil ' C(n ,7tA0"C, whereas mechanism (2) would predict a 12 ± n ranges of C(n ,nN) C reaction products; they may be peak in the angular distribution at close to 90° to the compared with similar results previously obtained for the direction of the incident pion. >2 n C(p,pn) C reaction induced by protons of comparable We have chosen the relatively simple thick-target 1 3 1 3 energies. " Within the limits of uncertainty, the FW and thick-catcher technique, employed previously " for BW values are equal, but the values of PW are studies of the nC{p,pn)nC reaction, to learn some of the 12 ± 11 significantly larger in the proton reaction, particularly at features of the recoil properties of the C(;t ,JtA') C the lower energies. reactions. The experiment involved irradiations of target- Analysis of our pion reaction data is under way in catcher stacks with pions followed by assay of the in terms of a two-velocity vector representation of the reac duced UC activity. The irradiations were performed at tion, based on a quasi-free scattering model for describ the P3 and LEP channels at LAMPF. The pion energies ing on a microscopic level how momentum is trans ranged from 90-350 MeV, and the exposures lasted ferred from the incident pion to the carbon nucleus. The about 30 min. velocity and kinetic energy of the recoiling nucleus will 2 The target stacks consisted of a 14.3-mg/cm -thick come from this analysis. In addition, a comparison with 2 graphite foil sandwiched between 25-um- (~5-mg/cm -) calculations based on the intranuclear cascade code thick beryllium catcher foils of the highest available ISOBAR plus the evaporation code OFF will be made. purity. Beryllium guard foils protected the stack from ex From these analyses we expect to be able to conclude ternally produced "C recoils. The stacks were irradiated something about the contributions of the DKO and ISE in two different orientations to the beam at each energy. processes to the nucleon-removal reactions in the carbon In experiments designed to yield the projected forward as a function of pion energy and pion charge. and backward ranges, the stack was mounted perpen 68 PROGRESS AT LAMPF July-Docamber 1981 Los Alamos National Laboratory Helium-Jet Transport of Fission and Spallation Reaction Products (Exp. 629, AB-Nucchem) (Los Alamos, Idaho National Engineering Lab., Univ. of Oklahoma) Spokesmen: M. E. Bunker and W. L. Talbert, Jr. (Los Alamos) and R. C. Greenwood (Idaho National Engineering Lab.) We are investigating the feasibility of using a helium- jet transport system coupled to an isotope separator to study short-lived radionuclides far from stability, produced with the H+ beam at LAMPF using high- energy, proton-induced fission and spallation reactions. The ultimate objective of this research is to determine the masses, spins, and moments of highly unstable nuclei, and in favorable cases to study the nuclear structure of these nuclei. The basic idea of helium-jet transport is that the reac tion products recoiling from a thin target foil are first stopped in flowing aerosol-loaded helium gas; radioac tive atoms then attach themselves to the aerosol particles and are swept out of the reaction chamber to a remote station through a small-diameter capillary tube. A major advantage of the technique is that essentially all elemen tal species ejected from the target can be transported to •TT (MeV) the ion source of a remote isotope separator where, according to recent experiments in the United States1,2 Fig. 1. and Europe,3 most elements — even refractory elements Energy dependence of tlte average projected range like molybdenum, technetium, palladium, ruthenium, and of nC from the 12C(Tc±,nN)1,C reactions. FW, PW, rhodium — can be successfully ionized. In contrast, the and B W correspond to the forward, perpendicular, targets used at existing major on-line separator facilities and backward ranges, respectively. at proton accelerators, such as the ISOLDE facility4'5 at CERN, have to be massive to compensate for the relatively low-beam currents available (<5 uA). The only REFERENCES elements that can be studied are those that can readily diffuse out of these elevated-temperature targets, that is, 1. S. Singh and J. M. Alexander, "Recoil Study of the Reaction those elements which are not refractory. In the helium-jet ,2C(p,pn)"C, Phys. Rev. 128, 711-719 (1962). technique, thin targets «10 mg/cm2) are used, with the result that very high beam currents are required in order n 2. S. Hontzeas, "Recoil Studies of the Reaction C(p,pn)"C from to produce a sufficient number of atoms for detailed Threshold to 85 MeV," Can. J. Chem. 46. 268-277 (1968). nuclear studies. The LAMPF accelerator is, in fact, uniquely capable of providing the high product yields 3. N. T. Porile, "Recoil Study of the l2C(p,pn) Reaction from Threshold to 150 MeV," Nucl. Phys. A130, 88-96 (1969). needed for mounting the proposed helium-jet-coupled separator facility. July-December 1981 PROGRESS AT LAMPF 69 Los Alamos National Laboratory The initial experiments ccnducted at LAMPF in 1981 It remains to be demonstrated whether the helium-jet have demonstrated that fiss'- products and spallation transport technique will work satisfactorily when beam products ejected from thin uranium, tantalam, and currents of >500 uA are incident on the target chamber. rhodium targets bombarded with up to 3 uA of 800-MeV A retractable target chamber that will eventually be test protons can be rapidly and efficiently transported over ed on Line A is being designed. The design will large distances using a relatively simple helium-jet emphasize minimization of the total transport time and system. A \-t target chamber was installed in the nuclear will incorporate helium-cooled entry and exit windows. chemistry cave near the end of the H" beam line. Helium containing NaCl aerosol flowed into the target chamber REFERENCES and back to a collection station 41 m from the target. The return flow was made through 1.6-mm i.d. capillary 1. R. A. Anderl, V. J. Novick, and R. C. Greenwood, Nucl. Instrum. tubing. With a chamber pressure of 2 atrn absolute, a Methods 186, 153 (1981). helium flow rate of 30 cm3/s, and an aerosol generator temperature of 600° C, overall transport efficiencies of 2. D. M. Moltz, Nucl. Instrum. Methods 186, 135 (1981). between 40 and 50% were observed for all nongaseous 3. A. K. Mazumdar et al., Nucl. Instrum. Methods 186, 131 (1981). reaction-product elements recoiling from the targets. The time delay from beam turn-on to the arrival of the first 4. H. L. Ravn, Phys. Rep. 54, 201 (1979). activity at the collection station was measured to be about 2.8 s, which is in reasonable agreement with 5. P. G. Hansen, Annu. Rev. Nucl. Sci. 29, 69 (1979). theoretical predictions.6'7 The median diameter of the NaCl aerosol particles was 0.04 urn. 6. J. Kruger and J. F. Nothling, J. Aerosol Sci. 10, 571 (1979). 7. C. WeifTenbach et al., Nucl. Instrum. Methods 125, 245 (1975). 70 PROGRESS ATLAMPF July-December 1981 Los Alamos National Laboratory Materials Science tion results for the yield strength (at 0.2% offset) and the uniform plastic strain for our samples. Irradiation of Technologically Important Metals For the 304 stainless steel and annealed Alloy 718 the with 800-MeV Protons Using the Isotope Produc yield strengths increased by about a factor of 3 whereas tion Facility at LAMPF the ductility dropped. In the bcc metals (tantalum and molybdenum) the yield strengths increased by at least a (Exp. 554, ISORAD) factor of 2. Tantalum samples retained significant duc (Los Alamos) tility at room temperature, but several molybdenum Spokesmen: R. D. Brown and J. R. Cost (Los Alamos) specimens broke at <0.2% strain. This suggests that the ductile-brittle transition temperature for molybdenum The goal of this experiment is to investigate the was raised above room temperature during irradiation, response of several metals, useful in accelerator as has been observed following neutron irradiation. technology, to irradiation with 800-MeV protons. The The results of a transmission electron microscopy metals investigated were grouped into two categories, (1) analysis of the irradiation-produced microstructure those important as vacuum-line windows and target clad before and after straining will be discussed in terms of dings, and (2) those denser metals of interest as spalla changes in mechanical properties for the 304 stainless tion neutron targets. The present work represents a steel samples. Also, a quantitative analysis of each preliminary study of the effects of low fluences (10" to 20 2 material's helium concentration will be made to test the 10 protons/cm ) of 800-MeV protons on the yield calculated results of Coulter et al.' strength, tensile strength, and ductility of samples of 304 stainless steel, Alloy 718, molybdenum, and tantalum. REFERENCE Tensile samples (0.75 or 1.5 mm thick) were directly water cooled during irradiation and were tested at room 1. C. A. Coulter, D. M. Parkin, and W. V. Green, "Calculation of temperature. Table I gives preirradiation and postirradia- Radiation Damage Effects of 800-MeV Protons in a 'Thin' Copper Target," J. Nucl. Mater. 67, 140 (1977). TABLE I PREIRRADIATION AND POSTIRRADIATION MECHANICAL PROPERTIES Yield Stress Uniform Plastic Strain Preirradiation Postirradiation Preirradiation Postirradiation Material MPa (psi) MPa (psi) (%) (%) 304 stainless steel 134 (19 500) 383 (55 000) 77 58 Annealed Alloy 718 552 (80 000) 889 (129 000) 38 23 Annealed Tantalum 141 (20 500) 290 (42 000) 36 12 Stress relieved Molybdenum 290 (42 000) 690 (100 000) 19 Stress relieved July-December 1981 PROGRESS AT LAMPF 71 Los Alamos National Laboratory Muon-Spin-Rotation (|iSR) Studies in Spin-Glass seived in the ferromagnetic specimen, whereas in the spin -1 Systems glass (Tg = 5.0 K) a much larger (>30 us ) and con (Exp. 499, SMC) siderably less well-defined anomaly was seen at T= Tg. (Los Alamos, Univ. of California at Riverside, Rice A major goal of future work in this alloy system will be Univ.) to understand this enormous difference. This will require Spokesmen: S. A. Dodds (Rice Univ.), R. H. Heffner samples of intermediate concentrations, as well as further (Los Alamos), and D. E. MacLaughlin (Univ. of Califor studies of the samples now available. nia at Riverside) We have refined our transverse-field measurements in J>dMn and confirmed that at high temperatures, A lies Work on Exp. 499 during the past year has concen well below the values calculated for inhomogeneous trated on two spin-glass alloy systems, AgMn and broadening in a paramagnetic dilute alloy. Measure + PdMn. The experimental program in the former system ments of u diffusion in magnetically tagged palladium has been practically completed, at least for temperatures plus 300-ppm gadolinium have confirmed that muons + in the presently accessible range above ~2.5 K. We are immobile below temperatures ~200K, so u briefly summarize our results to date. depolarization is due only to hyperfine field static and The nSR measurements in AgMn in zero field and in fluctuation properties below this temperature. The ob applied longitudinal and transverse fields up to 5 kOe served discrepancy, therefore, is not due to muon diffu have revealed several fundamental properties of the spin- sion. We have carried out computer calculations of the paramagnetic-state dipolar field at octahedral and glass transition and of elementary excitations in the spin- + glass state. The effect of fluctuation modes of limited tetrahedral interstitial u sites using a theory rigorous for arbitrary concentration.3 This calculation yields a cen impurity-spin amplitude has been observed in both the + u+ static internal field distribution and in the u+ dynamic tral u resonance line, unshifted from the position relaxation function. This is of importance because two calculated in the dilute limit and with approximately the basically different classes of elementary excitations, dilute-limit line width. Near-neighbor satellites are ob quasi magnons and barrier modes, may possibly be dis served, however, which average to a broad background tinguishable by the relative amplitudes of individual spin in a polycrystalline specimen. Thus the anomalously fluctuations. The experimental relaxation rate at tem narrow absorption lines observed are not due to geometrical effects of finite concentration. The remaining peratures approximately one-half Tg (glass temperature) is at least 50 times higher than expected on the basis of a possibility is that near-neighbor pairwise an- computer simulation1 of the quasi-magnon-mode fre tiferromagnetic interactions lead to reduced contribu tions to the static inhomogeneity. Although this quency distribution. Near and above Tg an anomalously large static distribution is induced by an applied field, mechanism seems to be the most reasonable candidate for the observed anomaly, the fact that the discrepancy is and the rapid slowing of impurity-spin fluctuations as Tg largest at temperatures of ~150 K seems to conflict with is approached from above is quenched appreciably in 4 fields <;1 kOe. We expect all these results to stimulate independent measurements, which give an interaction considerable further theoretical interest in spin-glass strength of ~40 K in temperature units. dynamics. We will finish work on the AgMn system by Further work in PdMn will concentrate on extending our measurements to below 1 K when our 3He understanding this anomaly through comparison of cryostat is completed. results from alloys of different concentrations. In addi Work on PdMn alloys is still in progress. Two sam tion, evolution of field and temperature dependences of ples with manganese concentrations of 2 and 7 at.% have muon relaxation rates as a function of concentration will been studied. The former is a ferromagnet because of yield information on the nature of the approach to an or long-range positive manganese-manganese exchange in dered state in the presence of increasing disorder in the teractions mediated by the exchange-enhanced host, impurity-spin configuration. These studies, together with whereas palladium plus 7-at.% manganese is a spin glass investigations of ferromagnetic spin-glass PdFeMn, will by virtue of direct near-neighbor anr/ferromagnetic cou be of importance in understanding how host-exchange plings.2 The uSR behavior of the two systems differs enchancement affects the interplay between random and markedly. A cusp-like anomaly in the zero-field uSR nonrandom impurity-spin configurations and dynamics -1 in diluio alloys. relaxation rate (AmM ~ 0.3 us at Tc = 5.6 K) is ob- 72 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory REFERENCES REFERENCES 1. L. R. Walker and R. E. Walstedt, Phys. Rev. B22, 3816 (1980). 1. A. P. Murani, Solid State Commun. 33, 433 (1980). 2. G. J. Niewenhuys, Adv. Phys. 24,515 (1975); and B. R. Coles, H. Jamieson, R. H. Taylor, and A. Tari, J. Phys. F5, 565 (1975). Fusion Materials Neutron Irradiations 3. R. E. Walstedt and L. R. Walker, Phys. Rev. B9, 4857 (1974). (Exp. 545, Radiation-Effects Facility) (Los Alamos; Joint Research Center, Tspra, Italy; 4. G. J. Niewenhuys and B. H. Verbeek, J. Phys. F7, 1497 (1977). Princeton Plasma Physics Laboratory; Chalk River Nuclear Laboratory) Spokesman: R. D. Brown (Los Alamos) Models for n+ Depolarization in Spin Glasses (Los Alamos) This experiment brings together several studies of M. Leon property changes from spallation neutron irradiation, which have primarily been of interest to fusion reactor + A number of models for the depolarization of u in programs. spin-glass systems have been formulated and implement An experiment by a group at Ispra, Italy will compare ed on the LAMPF Computer Facility VAX computer. It the damage produced by LAMPF spallation neutrons is hoped that some of these models will prove relevant with that produced in fast reactors, a 14-MeV neutron and useful in interpreting the large amount of spin-glass source, and (eventually) a (d,L\) source. Techniques to be uSR data being acquired at LAMPF. These models used include small-angle x-ray and neutron scattering should also help to clarify our thinking about the dif and transmission electron microscopy (TEM). Ron ferent physics aspects of the spin-glass systems. Dierckx, Spokesman for the group at Ispra, has sent us a At present the models fall into two classes, (1) com capsule of samples that has been irradiated to a fluence plete reorientation models, and (2) incomplete reorienta of ~1018n/cm2. The samples include single crystals of tion models. In class (1) the local internal magnetic field nickel, iron, and niobium, each about 1 cm3 in volume, + felt by the u. (always taken as static between jumps) is suitable for neutron-scattering investigations. Aluminum uncorrected in direction before and after a field fluctua tensile samples have been included, together with foils for tion, whereas in class (2), in addition to the fluctuating TEM and transmutation product analysis. The sample directionally uncorrected component, there is also a capsule contains activation foils for dosimetry and ther static component to the local internal field. For both mocouples to monitor the temperatures, which at peak classes of models the algorithms allow for external fields beam current have registered 140°C. Following cool either parallel or perpendicular to the initial polarization down, the samples will be returned to Italy for examina direction.* tion. Results will be compared with those for samples For class (1) we have included, in addition to (a) a irradiated at RTNS-II and EBR-II. Irradiation of ad single correlation time (exponential correlation function) ditional capsules is expected. for the internal field fluctuations, the possibility of (b) a Gary Taylor and Don McNeill (Princeton Plasma distribution of correlation times (again exponential Physics Laboratory) have submitted a number of sam correlation functions) and (c) nonexponential correlation ples for irradiation that are primarily connected with functions. There is some evidence that neutron scattering plasma diagnostics for the Tokamak Fusion Test Reac 1 favors (b) or (c). However, (c) gives difficulties with the tor (TFTR). Small diagnostic windows of crystalline physical requirement of homogeneity in time (at least quartz, fused silica, and zinc selenide have been with the functions we have investigated), so we will con irradiated to fluences of ~1017 n/cm2. The optical trans centrate on (b) and attempt to test its compatibility with mission of the windows was compared before and after the data. irradiation, and vacuum integrity was determined in ther mal cycling tests following irradiation. Fiber optics sam Compare Y. J. Uemura and T. Yamazaki, to be published (LT-16). ples have also been irradiated for the TFTR project. In use, the fiber optics will be placed near the reactor vessel July-December 1981 PROGRESS AT LAMPF 73 Los Alamos National Laboratory and will see a neutron spectrum similar to that at our The Effect of Dislocation Vibration on Void Radiation-Effects Facility. Samples irradiated to a Growth in Metals 2 fluence of 10" n/cm have shown losses in transmission (Exp. 407, Line B, Nuclear Chemistry Cave) and changes in the index of refraction. We are currently [Eidg. Institut fur Reaktorforschung (EIR)/SIN, Univ. of irradiating samples of three different fiber optic materials Illinois, Northwestern Univ., Massachusetts Institute of to compare such property changes. An experiment to ex Technology, New Mexico Institute of Mining and amine in situ transmission changes and possible Technology, Sandia Labs., Los Alamos] fluorescence is being planned. Experiments at extremely Cospokesmen: W. F. Sommer (Los Alamos) and D. S. high fluxes have demonstrated the time dependence of Phillips (Univ. of Illinois) transmission losses in fiber optics. It would be most interesting to see ii similar results can be observed at our The major purpose of this research has been to gain flux. information about radiation-produced point- One method of heating the plasma in a fusion reactor defect/dislocation interactions. The importance of these involves passing rf power through a ceramic window in studies stems from the fact that under bombardment by the reactor vessel. Increased power losses from radiation energetic particles a lattice atom can receive sufficient damage in these windows could result in their failure, energy to be removed from its lattice site; the basic John Fowler (Group CMB-5) it i.ow measuring the loss product is a Frenkel defect, a vacancy-interstitial pair. tangent in alumina and sapphire as a function of fre Further, when the bombarding particles are very quency to 50 MHz, following neutron irradiations to energetic (medium-energy neutrons and protons), the in 2 18 2 fluences between 10" n/cm afid 10 n/cm . Additional itial interaction can produce an energetic spallation samples of alumina and beryllia have been supplied by nucleus that then moves through the lattice and produces Oak Ridge; the loss tangent will be measured at frequen a number of Frenkel defects. Additionally, spallation cies as high as 100 GHz. Seven packets of these samples nuclei and evaporation nuclei enter the atomic inventory were irradiated in LAMPF run cycles 30-32; additional of the metal (or alloy) as an impurity. Dislocations are a irradiations are definitely planned. major sink for point defects (vacancies, interstitials, and Samarium-cobalt permanent magnets may be used on impurity atoms). Their configuration and concentration the. Proton Storage Ring if the material's magnetic play an important role in determining the microstructural properties are not greatly altered because of scattered evolution of a metal system subjected to a radiation en radiation. Samples of several permanent magnet vironment because they can strongly affect the mass materials have been irradiated for W. T. Hunter and E. transport and final configuration of the point defects. D. Bush (Group MP-8). Samples irradiated to This microstructural evolution is the cause for 1017 n/cm2 have shown a drop of 1-2% in magnetic field. mechanical property changes during irradiation. Stuart MacEwen (Chalk River Nuclear Laboratory in We recently completed an experiment (the initial phase Canada) has sent titanium tensile samples for irradiation. of LAMPF Exp. 407) that showed that void (collection A group of samples has been irradiated with Dierckx's of vacancies) formation was suppressed when, by the ap IB 2 samples to ~10 n/cm , and a second group has been plication of an external applied stress, dislocations were n 2 irradiated to ~10 n/cm . These samples will be shipped forced to move through the lattice. This work was to Canada for mechanical property evaluation. motivated by a theoretical prediction of Green and Many activation foils have been irradiated for R. Weertman.1 They considered the fact that in the void Reedy and P. Englert in connection with Exp. 691, growth temperature regime (0.35-0.5 Tm, where Tmis the "Simulation of Cosmic-Ray Production of Nuclides by absolute melting point) interstitials are much more Spallation-Produced Neutrons." mobile than vacancies. Thus, the interstitials diffuse rapidly to sinks such as dislocations, whereas the slower moving vacancies build up in concentration in the lattice. 74 PftCOHESS AT LAMPF July-December 1981 Lot Alamos Ntttionti Laboratory (This supersaturation is believed to lead to nucleation of 7.7 K and a magnetic transition at TM ~ 4.1 K. For voids.) Additionally, Green and Weertman considered x = I the system exhibits a magnetic transition at 7'M ~ the accepted theoretical explanation for void growth; dis 6.6 K, and for x = 0 it has only a superconducting tran locations have a bias towards the absorption of in- sition at Tsx 11.3K. terstitials, leaving a net positive number of vacancies for Transverse-field measurements in LuRh4B4 (x = 0) absorption at the void. The void is considered to be un show no motional narrowing for T < 200 K, indicating biased. They postulated that by causing dislocations to that the u4 is stationary in this temperature range. Thus, "sweep out" the lattice, the vacancy supersaturation under the assumption that the u* mobility is unaffected could be reduced and void formation would, according by changing rare-earth species (that is, x), the dynamic ly, be reduced. u+ relaxation rate A( 7") measured in the other rare-earth Our initial results2 support their prediction. One of our rhodium-boride compounds is due only to the fluctuating future goals is to improve our experiment by employing dipole fields produced by the rare-earth magnetic mo internal friction methods so that the forced dislocation ments. motion can be monitored during the irradiation. In HoRh4B4 (x = 1). we observed dynamic relaxation with the full muon asymmetry for 30 K < T <. 300 K in REFERENCES zero-applied field. At 7"~28K the magnetic specific heat shows a Schottky anomaly because of the 1. W. v Green and J. Weertman. "Increased Efficiency of a Disloca crystalline-electric-field (CEF) splitting of the Ho3+ J = 8 tion Line as a Sink for Vacancies when it Oscillates," Radiat. Eff. manifold. Comparison of uSR data for GdRh4B,, (see 22, 9 (1974). below) and HoRh4B4 indicates that the maximum in A(7*)(see Fig. l)seenatT= 10-30 K in the latter system 2. W. F. Sommer, "An Experimental Determination of the Effect of Cyclic Stress on Void Growth in Ultrahigh-Purity Aluminum dur is caused primarily by these CEF effects. Below ing Simultaneous 800-MeV Proton Irradiation." Ph.D. thesis. Uni T~ 10 K the uSR data show a reduced asymmetry versity of Illinois. April 1981. (about one-third), indicating the presence of a large (>40 us"') static field component produced by the onset of a ferromagnetic-like transition. The dynamic relaxa Muon-Spin-Rotation ()iSR) Measurements in tion shows a continual slowing down below TM\ no Selected Ternary Metallic Compounds sharp transition at TM is observed. Also, below TM we (Exp. 640, SMC) observed no definite frequencies in the muon time spec (Los Alamos, Univ. of California at Riverside, Rice trum, which, if observed, would be indicative of a unique Univ.) static field. Calculations for both octahedral and + Spokesmen: S. A. Dodds (Rice Univ.), R. H. He/fner tetrahedral u stopping si'^ lead one to expect frequen (Los Alamos), and D. E. MacLaughlin (Univ. of Califor cies of several megahertz, far below TM. Thus, the lack nia at Riverside) of observable frequencies might be traced to multiple stopping sites, which would tend to diffuse the spectrum. The goal of this experiment is to examine the proper A comparison of HoxLu,_xRh4B4 for x= 1 and 0.7 ties of selected ternary metallic compounds that exhibit (see Fig. 2) in the temperature range 50 K < T < 300 K both superconductivity and magnetic order. Specifically, at zero field reveals that A/x scales roughly with we wish to address the questions, (1) Does the onset of TITM(X). The data below 10 K are in striking contrast, superconductivity affect thz spin dynamics in the however; for x= 0.7 a shoulder in A(7) at Tx T$ is re paramagnetic state and thus modify the magnetic or vealed. Measurements on Gd07Luo 3Rh4B4 (see below), dering? and (2) To what extent does the onset of which exhibits no superconductivity at all, show that a ferromagnetic order immediately suppress superconduc shoulder cannot be caused by unusual effects of dilution tivity (that is, is there a spin-fluctuation regime in the of the rare-earth ions. Thus, the zero-field superconducting state)? We report on measurements in Ho0 7Lu0 3Rh4B4 data reveal an interesting effect of superconductivity on the magnetic-ion relaxation rate. the systems HoALu,_jtRh4B4 and GdxLu,_xRh4B4, made during the beginning phase of this experiment. This shoulder persists in applied longitudinal fields (H\\) The initial series of measurements for Exp. 640 were up to 1 kOe, but disappears at H|| = 5 kOe, possibly because at 5 kOe the applied field exceeds //c2 and chosen in the system Ho^Lu,_xRh4B4. For x = 0.1 this system exhibits a superconducting transition at 7$ x destroys the superconducting state. Above T = 35K, July-December 1981 PROGRESS AT LAMPF 75 Los Alamos National Laboratory IWU - "i iniij I II 1 llll| 1 M= -J I I Mill !—I I I llllj 1—n= 1 I iITT j 1 11 i? D o 7 10 •» 0 Z < 0 \ o UJ ° °z EC r 5 HoRr.4e4 I 0 FULL ASYMMETRY Ho07Lu03Rh«S4 • REDUCED ASYMMETRY _ A FULL ASYMMETRY 1 O N RELAXATIO A REDUCED ASYMMETRY 1 °' 0.1 ~ The initial set of measurements on HoiLu,_jCRh4B4 asymmetry to one-third the value measured for T> 6 K, described above left two major unanswered questions, indicating a sharp phase transition accompanied by the (1) the effect of the CEF splitting on A(T) for T > 35 K, onset of a large static component in the relaxation func and (2) the effect on A(7) of dilution of the magnetic ion tion. The muon dynamic relaxation rate then decreases in the absence of superconductivity. For these reasons as the temperature is lowered below TM. This sharp tran we chose to study the GdxLu!_^Rh4B4 system. For large sition at 7V = 5.5 K is destroyed by a 5-kOe applied gadolinium concentrations (encompassing x > 0.7), this field. The longitudinal field dependence of A at compound exhibits no superconductivity in the tem r=5.5K is monotonically decreasing, reaching a perature range of interest and thus the effects of dilution plateau at about H<\ = 1-2 kOe, and remaining roughly without superconductivity can be studied. Furthermore, constant between 2 and 5 kOe. Very analogous behavior 76 PMOOREMATLAMPF Juty-Decer'jer 1581 Lot Alamos National Laboratory in both a zero- and an applied-longitudinal field is ob set of superconductivity on holmium moment dynamics served in Gd0,7Lu0.3Rh4B4, showing no unusual effects of for x = 0.7. Further experiments in related systems are rare-earth ion dilution. planned to clarify the nature of this effect. The most interesting observation in this initial series of experiments is undoubtedly the striking effect of the on July-December 1981 PROGRESS AT LAMPF 77 Los Alamos National Laboratory Biomedical Research resulting in about 600 uA of proton current on the biomedical pion target and yielding dose rates from 12 to Pion Therapy Beam Development and 18 rad/min/Y. The average treatment volume is about 2 t for single parallel-opposed fields (abutting) during each Characterization treatment cycle, so the overall average treatment volume (Exps. 270 and 271, Biomed) is probably closer to 2.5 I. (Los Alamos, Univ. of New Mexico) The narrow Bragg peaks of the pion beams are spread Spokesmen: M. Paciotti (Los Alamos) and A. Smith in depth by the use of a dynamic range shifter. The range (Univ. of New Mexico) shifter is computer controlled and can be programmed to produce spread peaks of varying dimension and shape, The catalog of broad beams for static treatments has ranging in depth from 3-14 cm in 1-cm intervals. A series been expanded to provide fields with transverse dimen of such range modulation functions has been developed sions up to 20 cm at each of three momenta correspond for each momentum (148, 167, and 190 MeV/c). This is ing to nominal depth penetrations of 12, 16, and 23 cm. necessary because the peak-to-plateau ratio, beam con Fan beams for dynamic treatments have been prepared tamination (electrons and muons), and momentum at several channel momenta, and extensive beam tuning spread (resulting in differences in the full width at half and dosimetry have been performed. Measured beam maximum of the spread peak) are different for each data have been provided for a three-dimensional momentum. For each spread peak it is possible to tailor treatment-planning code PIPLAN, with particles identified the slope of the physical dose and consequently the dis by position, angle, momentum, and type — that is, pion, tribution of stopping pions. It is also possible to produce muon, or electron. spread peaks with uniform total dose, uniform high- An experimental method has been developed for linear-energy-transfer (LET) dose, or uniform detecting muons resulting from pier, decay, using mul- biologically effective dose. tiwire proportional counters located before and after the The range-modulation function describes the thickness beam-shaping section of the channel. Analysis of these of a bellows-controlled column of oil in the beam path vs data has been facilitated by the use of a ray-tracing code. time. The range-modulation development code takes A new pyrocarbon target has been installed in the measured, central-axis, unmodulated total and high-LRT biomedical channel and is considered nearly optimum for distributions, and by applying time weights offsets each high-intensity operations. The target can be set by the curve by prescribed shifts in depth, sums all the offset operator to maintain constar" electron contamination. A curves together, and renormalizes to obtain the resultant multiwire chamber has been constructed and tested for modulated total and high-LET depth-dose curves. The use as a beam-profile monitor. program then uses a relative-biological-eflectiveness Considerable dosimetry has been directed toward (RBE) model to calculate the effective dose. The range- providing characterization for a large variety of patient modulation functions have been completely redesigned, beams: broad, essentially parallel beams for static treat based on data obtained from gel-tube cellular experi ment; beams focused in one dimension and broad in the ments designed to measure cell-killing uniformity, to ac perpendicular dimension for one-dimensional dynamic complish greater uniformity in biological effect for treatment; and beams focused in two dimensions for single-field treatments, and to confirm biological uni two-dimensional dynamic treatment. For the static formity of treatments performed with opposed, overlap beams, three beam sizes (small, medium, and large) have ping portals. been developed and characterized for each of three An automated data-acquisition and analysis system penetrations. Target volumes requiring larger field sizes has been developed for dosimetry measurements on the are treated with combinations of abutted fields. pion therapy beam using a PDP-11/70 computer and Dose rates for the pion therapy beams are a function CAMAC interface. A multiple ionization chamber array of beam momentum, the beam tune (size) for a given (MICA) system, with associated software control, has momentum, and the size of the spread-peak region. been developed for dosimetry measurements. This Typical dose rates for the beams range from 0.02 to system increases dosimetry data-acquisition rates by a 0.03 rad/min/? for each microampere of proton beam factor equal to the number of data channels in use. The current on the biomedical pion target. In the summer of system has been tested and used with a linear array of 10 1982 the proton beam current will be raised to 750 uA, ionization chambers. 78 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Accurate microdosimetry data are required for input a distinctly different dose distribution, separate calcula to the algorithms used in the calculations of RBE, pion- tions are required for each particle type. To model an ac effective dose, and range-shifter functions. Such data are tual beam, then, requires an accurate phase-space rep obtained from a variety of experimental techniques, in resentation of pencil beams. PIPLAN uses individually cluding Rossi-chamber proportional counters, solid-state measured trajectories for each beam tune, with the detectors (totally depleted lithium-drifted silicon), and spatial coordinates, angles, momentum, and particle type aluminum activation measurements. Rossi-chamber identified. measurements are used as the primary source of To improve the accuracy of PIPLAN, considerable ef microdosimetric data, but are time consuming. fort has been devoted to development and incorporation Therefore, one or two Rossi-chamber spectra are ob of sophisticated models for beam smoothing, neutron tained for each beam tune and additional data are ob dose caused by in-flight interactions in the plateau as tained from either solid-state detectors or aluminum ac well as in the peak region, multiple scattering through tivation, both of which permit rapid data collection. tissue inhomogeneities and air gaps between treatment These are normalized by comparison with the Rossi- appliances, range-modulation effects, external appliance chamber data to obtain complete information on the effects (notably neutrons produced from pions stopping spatial variations of high-LET dose for all therapy within the collimator), improved spatial resolution, and beams. contour processing. A new computer code was written to For biological experiments requiring special small- reconstruct the same kind of image as digital x-ray volume beams, custom collimatois and/or boluses have radiography from integrated CT images, and automatic been fabricated for each experiment and dosimetry has methods and algorithms have been developed and been performed using a combination of ion chambers implemented to transcribe CT-scanner regions of interest and thermoluminescent detectors. Microdosimetric (ROIs) to vector contours in treatment-planning measurements have also been taken to aid in the inter programs. A new display capability was developed to pretation of results. superimpose pion-dose distributions on patient CT data on the cathode ray tube (CRT) of the EMI 7070 scanner. Two supporting libraries were completed: a beam-tune Treatment-Planning Code Development library and a range-shifter-function library. New models (Los Alamos) were also installed to account for the dose deposited by P. Berardo electrons from muon decay in the patient and by muons from pion decay in both the beam channel and the Dynamic treatments require the use of the three- patient. Improvements to the case-file system (where all dimensional treatment-planning code, PIPLAN. This code treatment-planning data for a given patient are collect uses a ray-tracing model where actual pion trajectories in ed), to the resolution and reduction of CT data, and to the three-dimensional volume represent pencil beams. folding CT data into pion-dose calculations were also PIPLAN calculates a dose distribution by summing the implemented. contributions of individual pencil beams as they pass through various parts of the anatomy [determined by computed-tomography (CT) scans] and clinical ap Biomedical Instrumentation pliances. The dose distribution for a pencil beam is (Los Alamos) predetermined analytically in water as the sum of its sep J. D. Doss arate components, including the effects of in-flight in teractions and straggling. This dose is distributed in Hyperthermia depth as a function of water-equivalent range along the trajectory, and radially as a function of multiple At the request of a physician in Shanghai, two Los Coulomb scattering (which is both geometry and energy Alamos hyperthermia sources with custom-designed dependent). Distributing this dose entails accumulating probes have been loaned to the People's Republic of at each point of interest the relative amount of dose ii China. Neurosurgeons in China intend to use localized that point from each pencil beam. Because the treatment'" hyperthermia in combination with conventional surgical beams contain spatially nonuniform ratios of pions, techniques to treat brain tumors. The Los Alamos rf muons, and electrons, and because each particle type has probes will generate elevated temperatures in the region July-December 1981 PROGRESS AT LAMPF 79 Los Alamos National Leborelory where the bulk of the tumor has been surgically re We have had several requests from ophthalmologists moved. Information on clinical results will be shared with for copies of our computer program ROW, which is used the United States. to analyze corneal shape and optical power distribution. Drawings have been sent recently to two institutions Because of the level of interest in using this code for that wish to construct b'-!erthermia units based on Los clinical applications, we have rewritten the code in a Alamos prototype instruments. The Western Instrument form of BASIC that is quite similar to that used on most Company of Denver plans to produce a commercial in of the inexpensive desk-top computers likely to be found strument for veterinary applications, and Washington in a physician's office. University in St. Louis plans to construct six to eight units for biological experiments. A hyperthermia instrument loaned to the National Calculational Support Cancer Institute of Peru is being used in combination (Los Alamos) with radiation therapy for experimental treatment of D. J. Brenner melanoma. We have also designed special instrumenta tion for use in investigations of the effects of hyperther Development of a Realistic Deexcitation Code for mia on fungus infections. The first experiment, in Light Nuclei collaboration with the University of New Mexico School of Medicine, will occur in December. A proposal is being The neutron radiotherapy programs require detailed considered, from physicians at the Truman Medical Cen high-energy neutron cross sections on light nuclei. We ter in Kansas City, for the use of localized rf hyperther have improved the intranuclear cascade code VEGAS by mia in the treatment of cervical intraepithelial neoplasm. adding a deexcitation code based on the Fermi breakup This lesion is evidently a precursor of malignancies in the model, which includes the following features. female reproductive tract, and is presently treated with 1. A breakup of up to seven particles is allowed. electrocautery, cryosurgery, or laser beams. 2. Particle-unstable levels are allowed as intermediate Our computer code FIELD, which is used to calculate states in a sequential breakup. Realistic nuclear electric field strength and power density in tissue, has data are used for these intermediate states. recently been rewritten so that it will be much easier to 3. Two-body breakup channels use a Coulomb use for predicting the applied power distribution in barrier penetration factor based on Coulomb wave hyperthermia treatments. A manual has been written to functions. Multiparticle breakup uses a threshold facilitate the use of this code at other institutions. adjusted for Coulomb energy. 4. Two-body breakup of a given level is restricted to conserve parity and is inhibited by an angular- Ophthalmology momentum barrier penetration factor. The results of the code (double-differential and angle- A variety of the multipolar circulating saline probes integrated production cross sections) have been com have been constructed at Los Alamos and tested, at the pared with some recent measurements at 27.4, 39.7, and McGee Eye Institute (MEI) in Oklahoma City. Although 60.7 MeV taken at the University of California at Davis. the probes exhibit all the advantages over the monopolar In general, excellent agreement is found, with the excep probe outlined previously, there is generally more tion of secondary deuteron-production cross sections, damage to the corneal inner cell layer (endothelium) than which are underestimated because direct-transfer reac was expected. While tests of these probes continue, we tions are not included in the formalism. As an example, are constructing more sophisticated versions of the the angle-integrated proton production cross section probe. Corneal-shape-modification instrumentation is es from the ]2C(n,xp) reaction at 39.7 MeV is shown in sentially complete for loan to the University of New Fig. I. Also, kerma factors (kinetic energy released in Mexico School of Medicine, but the actual start of ex matter) have been calculated with the code. These factors periments will probably be delayed until further results are essential in high-energy neutron dosimetry, but until are forthcoming from the experiments at MEI. now calculations of kerma have been based on un realistic nuclear models. 80 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 12( 3(n.xp) ENERGY = 40 MeV predictions to experiments done at the nanometer level in a very low-pressure cloud chamber. 10- Currently, the code is being modified so that the " i histories of the free radicals formed by ionizing events Tk-u_ are recorded. These free radicals, particularly the hydroxy! radical, have been implicated in cell killing in a > 0.1: (i Details of energy deposition in small sites (nanometers up to micrometers) are known to be important for the 005 J 0 10 20 30 predictions of biological damage. In the case of neutrons, ENERGY (MeV) secondary charged particles and tertiary electrons must Los Alamos all be tracked to calculate the energy deposition in a specific site size. Fig. 1. A system to perform such calculations has been Angle-integrated production cross section of developed that involves (1) precalculating electron tracks protons emitted after 40-MeV neutrons are inci of various energies, which are then stored; (2) dent on [2C. Points: experiment from the Uni precalculating heavy charged-particle tracks (protons, versity of California at Davis. Histogram: this deuterons, and a particles), using experimental and calculation. theoretical information on secondary electron- production spectra and then superimposing suitable elec tron tracks on the field. These charged-particle tracks are Development of a Low-Energy Electron Transport then stored; and (3) calculating neutron tracks using calculated secondary charged-particle-production spec Code tra and superimposing suitable charged-particle tracks on the field. An electron transport Monte Carlo code has been developed primarily for use with low-energy (1 < E < As an example of the results of such a system, a 105 eV) electrons in water vapor. Interest in a low-energy calculation of the spectrum of energy deposited in a 1- transport code in water has been generated by the um sphere by 14-M'JV neutrons is shown in Fig. 2 development of several models of biological damage, all (points; compared with experimental data from the of which require quantities that must be calculated from Radiological Research Accelerator Facility (RARAF) at radiation maps, that is, lists of all energy-deposition Brookhaven (full line). events in the field, their positions, types, and energies. In the code, cross sections for all the different possible ionizations and excitations are included together win? Interpretation of Soft X-Ray Biological Data using elastic scattering, which is considered on an event-by- Low-Energy Electron Transport Code event basis rather than by using a multiple-scattering for malism. Extensive experiments have been performed at the Extensive corroborative work has been performed Medical Research Council (MRC) in England with very with the code, particularly by extending it to include soft x rays, whose secondary electrons have a range of a various other gases and by successfully comparing its few nanometers. These x rays are a fine probe of the possible biological interactions occurring between nearby July-Decemher 1981 PROGRESS AT LAMPF 81 Los Alamos National Laboratory NEUTRON ENERGY = 13.966 MeV sites of energy deposition within the cell nucleus after 0.5 -| irradiation. We have interpreted the data using the model where tj(x) is a function of the x-ray field, which we calculate with the low-energy electron transport code de scribed above, );,• is related to the measured biological damage, and y(x) is a function specific to the cell type used, describing the interaction between energy- deposition events in the nucleus. Given t, and \[, we use an unfolding technique to derive y. Preliminary analysis i' lb 100 IOOO reveals an interaction function y, limited to about 3 nm, y (keV/ym) considerably smaller than previous calculations in which Los Alamos less sophisticated calculations of t{x) were used. Accurate data on y is considered by many scientists to Fig. 2. be a vital prerequisite to future calculations of the effects Microdosimetric spectrum of lineal energies for of low doses of radiation on mammalian systems, in neutrons of mean energy 13.966 MeV. Full curve: cluding man. experimental data from RARAF. Points: this calculation. 82 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory MP-Division Publications: Papers Submitted for J. B. McClelland et a!., "Analyzing Power for pp and pd Publication Elastic Scattering in the Coulomb-Nuclear Interference Region," 5th Int. Symp. Polarization Phenomena in G. H. Sanders, H. S. Butler, M. D. Cooper, G. W. Hart, Nuclear Physics, Santa Fe, New Mexico, August 1980. CM. Hoffman, G. E. Hogan, H. S. Matis, V. D. Sandberg, R. A. Williams, E. B. Hughes, J. Rolfe, F. Irom, G. J. Igo, J. B. McClelland, and C. A. Whitten, S. Wilson, and H. Zeman, "Intelligent Trigger Processor Jr., "Elastic p-p Scattering at 796 MeV in the Coulomb- for the Crystal Box," submitted to Topical Conf. on the Nuclear Interference Region," to be published in Phys. Application of Microprocessors to High-Energy Physics Rev. C. Experiments, CERN, Geneva, Switzerland, May 1981. F. Irom, G. J. Igo, J. B. McClelland, and C \. Whitten, W. Cornelius, "Mixing of Final State Spin Components Jr., "Small Angle Elastic l>d Scattering at 796 MeV," in the HRS," Los Alamos National Laboratory report submitted to Phys. Rev. Lett. LA-9130-MS (1981). G. R. Smith, J. R. Shepard, R. L. Boudrie, G. S. Adams, C. L. Morris, W. B. Cottingame, S. J. Greene, C. J. Har T. S. Bauer, G. J. Igo, G. Pauletta, C. A. Whitten, Jr., vey, C. F. Moore, D. B. Holtkamp, S. J. Seestrom- A. Wriekat, B. Hoi*t*d, and G. W. Hoffmann, "The Morris, and H. T. Fortune, "Indication of A-Hole Con (p,d) Reaction at 800 MaV," submitted to Phys. Rev. C. figurations in 12C (15.11)," submitted to Phys. Lett. W. D. Cornelius, "Recent Results from LAMPF Optical C. F. Moore, C. J. Harvey, C. L. Morris, W. B. Cot Pumping Studies," invited talk at the Mtg. Japanese tingame, S. J. Greene, D. R Holtkamp, and H. T. For Phys. Soc. on Heavy Ion and Polarized Ion Sources, Os tune, "Evidence for a Spin-Flip Giant Resonance in aka, Japan, October 1981. l2C(7t,7t')," submitted to Phys. Rev. Lett. C. M. Hoffman, "The Search for Muon Number Viola G. R. Swain, "Power Reduction by Changing the Design tion at LAMPF," presented at Workshop on Nuclear Particle Phase," presented at Linear Accelerator Conf., and Particle Physics at Energies Up to 31 GeV, Los Santa Fe, New Mexico, October 1981 and to be Alamos, New Mexico, January 1981. published in the proceedings. W. F. Sommer, "An Experimental Determination of the M. W. McNaughton, E. P. Chamberlin, J. J. Jarmer, Effect of Cyclic Stress on Void Growth in Ultra-High N. S. P. King, H. B. Willard, and E. Winkelmann, "Spin Purity Aluminum During Simultaneous 800-MeV Correlation A„„ and Analyzing Power A in p;j —* pp at Proton Irradiation," Ph.D thesis. University of Illinois, 643 MeV," submitted to Phys. Rev. C. 19dl. M. W. McNaughton, B. E. Bonner, W. D. Cornelius, W. F. Sommer, W. V. Green, L. W. Hobbs, C. A. Wert, E. W. Hoffman, O. B. van Dyck, R. L. York, R. D. Ran- "An Experimental Determination of the Effect on Void some, C. L. Hollas, R. J. Riley, and K. Toshioka, "Spin Formation in Aluminum During Simultaneous 800-MeV Transfer Measurements for pp —>• pp at 800 MeV," sub Proton Irradiation," presented at the 110th AIME An mitted to Phys. Rev. C. nual Mtg., Chicago, February 1981. C. J. Orth, W. R. Daniels, B. J. Dropesky, R. A. R. D. Ransome, C. L. Hollas, P. J. Riley, B. E. Bonner, Williams, G. C. Giesler, and J. N. Ginocchio, "Products W. D. Cornelius, O. B. van Dyck, E. W. Hoffman, of Stopped-Pion Interactions with Cu and Ta," Phys. M.W. McNaughton, R. L. York, S. A. Wood, and Rev. C21, 2525 (1980). K. Toshioka, "Measurement of the p-C Analyzing Power Between 100 and 750 MeV and the p-Be Analyz K. M. Hanson, J. N. Bradbury, T. M. Cannon, R L. ing Power at 780 MeV," submitted to Nucl. Instrum. Hutson, D. B. Laubacher, R. J. Macek, M. A. Paciotti, Methods. and C. A. Taylor, "Computed Tomography Using Proton Energy Loss," to be published in Phys. Med. Biol. July-Dacerr oer :Q81 PROGRESS AT LAMPF 83 Los Alamos National Laboratory R. D. Ransome, S. J. Greene, C. L. Hollas, B. E. Bonner, G. R. Swain, "Power Reduction by Changing the Design M. W. McNaughton, C. L. Morris, and H. A. Thiessen, Particle Phase," 1981 Linear Accelerator Conf., Santa "A Polarimeter for Protons Between 100 and 800 MeV," Fe, New Mexico, October 1981. submitted to Nucl. Instrum. Methods. C. M. Hoffman, "How to Build a Very Low Momentum J. D. Doss, R. L. Hutson, J. J. Rowsey, and R. Brown, K~ Beam at a Kaon Factory," to be published as a Los "Method for Calculation of Corneal Profile and Power Alamos National Laboratory informal report. Distribution," Arch. Ophthalmol. 99, 1261-1265 (1981). J. R. Cost and W. F. Sommer, "Response of Metallic J. J. Rowsey, J. D. Doss, "Preliminary Report of Los Glasses Fe40Ni40P14B6 and Feg0B20 to Irradiation with Alamos Keratoplasty," Ophthalmology 88, 755-760 800-MeV Protons, 2nd Topical Mtg. on Fusion Reactor (1981). Materials, Seattle, Washington, August 1981. J. D. Doss, "Field Manual: Calculations of Electric D. H. Fitzgerald, F. O. Borcherding, W.J. Briscoe, Fields in Conducting Media," Los Alamos National B. M. K. Nefkens, and D. I. Sober, "Efficiency of a Laboratory report LA-9012 (October 1981). Single-Converter Detector for Monochromatic Photons Between 25 and 234 MeV," submitted to Nucl. Instrum. J. D. Doss, "Calculation of Electric Fields in Conductive Methods. Media," submitted to Medical Physics. C. Boekema, R. H. Heffner, R. L. Hutson, M. E. Schillaci, J. L. Smith, A. B. Denison, S. A. Dodds, and D. B. Holtkamp, S. J. Seestrom-Morris, S. Chakravarti, D. E. MacLaughlin, "uSR Measurement of Rare-Earth D. Dehnhard, H. W. Baer, C. L. Morris, S. J. Greene, Moment Dynamics in the (Lutetium, Holmium) and C. J. Harvey, "n+/n~ Cross Section Ratios Larger Rhodium Boridt Ternary Alloy System," 27th Ann. than the Free Pion-Nucleon Value Observed in Pion In Conf. on Magnetisn and Magnetic Materials, Atlanta, elastic Scattering from 14C," submitted to IX Int. Conf. Georgia, November ' 981. on High-Energy Physics and Nuclear Structure, Ver sailles, France, July, 1981. R. H. Heffner, M.Leon, M. E. Schillaci, D. E. MacLaughlin, and S. A. Dodds, "uSR Studies of the Spin Glass Silver Manganese," 27th Ann. Conf. on J. F. Harrison, "RSX-11M Device Commons," 1981 Magnetism and Magnetic Materials, Atlanta, Georgia, Fall Mtg. of DECUS U. S. Symp., Los Angeles, Califor November 1981. nia, December 1981. J. A. McGill, L. G. Atencio, and C. L. Morris, "A Fast, K. E. Christensen, G. A. Bennett, and W. F. Sommer, Low-Mass Detector for Charged Particles," submitted to "An In Situ Mechanical-Radiation Effects Test Capsule Nucl. Instrum. Methods. for Simulating Fusion Material Environments," 2nd Topical Mtg. on Fusion Reactor Materials, Seattle W. J. Briscoe, D. H. Fitzgerald, B. M. K. Nefkens, and Washington, August 1981. M. E Sadler, "P3 Channel Beam Measurements at LAMPF," submitted to Nucl. Instrum. Methods. D. L. Grisham and J. E. Lambert, "Waste Management at LAMPF," Am. Nucl. Soc. 1981 Winter Mtg., San D. L. Grisham, "Design and Drafting Personnel at Los Francisco, California, November 29 - December 4, Alamos," 2nd DOE Workshop on Design Automation 1981. and Computer-Aided Design, Albuquerque, New Mex ico, October 1981. J. A. McGill, "Inclusive Proton Spectra and Total Reac tion Cross Sections for Proton-Nucleus Scattering at M. Zaider, D. J. Brenner, K. Hanson, and G. Minerbo, 800 MeV," Los Alamos National Laboratory report LA- "An Algorithm for Determining the Proximity Distribu 8937-T. tion From Dose-Averaged Lineal Energies," submitted to Radiat. Res. 84 PROOR E88 AT LAMPF July-December 7987 Los Alamos National Laboratory P. Berardo, S. Zink, M. Paciotti, and J. Bradbury, Lutetium Rhodium Boride Ternary Alloy System," 27th "Criteria and Techniques for Three-Dimensional Treat Ann. Conf. on Magnetism and Magnetic Materials, ment Planning," to be published in Proc. Int. Workshop Atlanta, Georgia, November 1981; and to be published on Pion and Heavy Ion Radiotherapy: Preclinical and in J. Appl. Phys. June 1981. Clinical Studies, Vancouver, British Columbia, July 1981. D. M. Manley, "Measurement and Isobar-Model Analysis of the Doubly Differential Cross Section for the + + J. F. Dicello and D. J. Brenner, "Radiation Quality of n Produced in rc~p —»• it 7Tn," submitted to Phys. Rev. Beams of Negative Pions," to be published in Proc. Int. Workshop on Pion and Heavy Ion Radiotherapy: J. M. Moss, T. A. Carey, S. J. Seestrom-Morris, N. J. Preclinical and Clinical Studies, Vancouver, British DiGiacomo, J. B. McClelland, G. F. Bertsch, Columbia, July 1981. O. Scholten, G. S. Adams, M. Gazzaly, N. Hintz, and S. Nada, "Excitation of the Giant Resonance Continuum R. H. Heffner, M. Leon, C. E. Olsen, M. E. Schillaci, with Intermediate-Energy Protons," submitted to Phys. S. A. Dodds, and D. E. MacLaughlin, "Muon Rev. Lett. Depolarization by Low-Lying Excitations in Spin-Glass AgMn," submitted to Phys. Rev. Lett. H. Baer, D. Dehnhard, M. Silbar, and O. van Dyck, "Unique Nuclear Spectroscopy with Pions," submitted J. N. Bradbury, "Medical Uses of Accelerators," Proc. to CERN Courier. 6th Int. Summer College on Physics and Contemporary Needs, Islambad, Pakistan, June 15 - July 2, 1981. C. M. Hoffman, "On the Possibility of Studying vc and v~e Interactions," Los Alamos National Laboratory J. D. Doss, "Calculation of Electric Fields in Conductive report LA-8760-MS. Media," submitted Med. Phys. H. J. Emrich, G. Fricke, M. Hoehn, M. Mallot, LAMPF Experimental Program Reports and H. Miska, B. Robert-Tissot, D. Ryche, L. Schaller, and Publications L. Schellenberg, H. Schneuwly, B. Shera, H. G. Sieberl- ing, R. Steffen, H. D. Wohlfahrt, and Y. Yamazaki, (Exp. 5) R. E. Chrien, T.J. Krieger, R.J. Sutter, "Systematics of Radii and Nuclear Charge Distributions M. May, H. Palevsky, R. L. Stearns, T. Kozlowski, and Deduced From Elastic Electron Scattering, Muonic X- T. Bauer, "Proton Spectra from 800 MeV Protons on Ray and Optical Isotope Shift Measurements," invited Selected Nuclides," Phys. Rev. C21, 1014 (1980). paper presented at 4th Int. Conf. on Nuclear Far From Stability, Helsingor, Denmark, June 1981. (Exp. 9) K. G. Boyer, W. J. Braithwaite, W. Cottingame, S. J. Greene, C. J. Harvey, D. B. Holtkamp, L. E. Smith, H. H. Howard and J. C. Allred, "Vertices of Entropy in C. F. Moore, C. L. Morris, H. A. Thiessen, G. S. Blan- Economic Modeling," Joint Mtg. of Operations pied, G. R. Burleson, J. Davis, J. S. McCarthy, R. C. + Research Society of America and The Technical Infor Minehart, and C. A. Goulding, "Comparison of n and mation for Management Society, Houston, Texas, Oc 7i~ Inelastic Scattering from Low-Lying Collective States tober 1981. of 40'«^4-48Ca and 54Fe," Proc. Int. Conf. on Nuclear Physics, Berkeley, California, August 1980, p. 695. Y. Tanaka, D. B. Laubacher, R. M. Steffen, E. B. Shera, H. D. Wohlfahrt, and M. V. Hoehn, "Ground State (Exp. Ill) J. C. Hill, R. F. Petry. and K. C. Wang, Quadrupole Moments of lw,157Gd by Muonic X Rays," "Identification and Decay of Neutron-Rich 39S," Phys. submitted to Phys. Lett. B. Rev. C21, 38^ (1980). C. Boekema, R. H. Heffner, R. L. Hutson, M. Leon, (Exp. 122) R. J. Powers and K.-C. Wang, "Experimental M. E. Schillaci, J. L. Smith, S. A. Dodds, and D. E. Study of Pionic Ca and Ti and Examination of the Pion- MacLaughlin, "Muon Spin Rotation Measurement of Nuclear Potential for Low-Z Nuclei," Nucl. Phys. A336, Rare-Earth Moment Dynamics in the Holmium 475-498 (1980). July-December 1981 PROGRESS AT LAMPF 85 Los Alamos National Laboratory (Exp. 139) G. S. Kyle, N. M. Hintz, M. A. Oothoudt, and C. J. Harvey, "Strong Cancellations of Neutron and M. Kaletka, P.M. Lang, H. Nann, K. K. Seth, D. K. Proton Transition Amplitudes Observed in Pion Inelastic McDaniels, P. M. Varghese, T. Kozlowski, D. G. Scattering from MC," Phys. Rev. Lett. 47, 216 (1981). Madland, C. L. Morris, J. C. Pratt, J. F. Spencer, N. Tanaka, H. A. Thiessen, G. S. Blanpied, G. W. (Exp. 243) D. R. Fortney and N. T. Porile, "Differential Hoffmann, R. P. Liljestrand, J. C. Fong, G. J. Igo, R. J. Ranges of Sc Fragments from the Interaction of 238U Ridge, and C. A. Whitten, "Elastic and Inelastic Scatter with 0.8-400-GeV Protons," Phys. Rev. C2I, 664 ing of 800-MeV Protons by i8Ni," Phys. Lett. 91B, 353- (1980). 357 (1980). (Exp. 243) D. R. Fortney and N. T. Porile, "Angular (Exp. 142) W. W. Wilci.e, M. W. Johnson, W. U. Distribution of Sc Fragments from the Interaction of Schroder, J. R. Birkelund, J. R. Huizenga, J. C. Browne, 238U with 0.8-400-GeV Protons," Phys. Rev. C21, 2511 and D. G. Perry, "Actinide Muonic Atom Lifetimes (1980). Deduced from Muon-Induced Fission," Phys. Rev. C21, 2019 (1980). (Exp. 243) S. Pandian and N. T. Porile, "Angular Dis tribution and Differential Ranges of Ba Products from (Exp. 144) L. B. Auerbach, ?! Haik, V. L. Highland, the Interaction of 238U with 0.P-400-GeV Protons," W. K. McFarlane, R. J. Macek, J. C. Pratt, J. Sarracino, Phys. Rev. C23, 427 (1981). and R. D. Werbeck, "A New Search for the Allowed Decay JT° — 4y," Phys. Lett. 90B, 317 (1980). (Exp. 247) C. J. Orth, W. R. Daniels, B. J. Dropesky, R. A. Williams, G. C. Giesler, and J. N. Ginocchio, (Exp. 146) R. S. Raymond, R. E. Anderson, R. L. "Products of Stopped-Pion Interactions with Cu and Boudrie, J. Piffaretti, N. S. P. King, T. G. Masterson, Ta," Phys. Rev. C21, 2524 (1980). C. L. Morris, R.J. Peterson, and R. A. Ristinen, "Ex citation of Giant Resonances in "8Sn Via 130-MeV Pion (Exp. 258) S. Frankel, W. Frati, C. F. Perdrisat, and Scattering," Proc. Int. Conf. Nuclear Physics, Berkeley, O. B. van Dyck, "Backward Production oi High-Energy California, 1980, p. 263. Protons in p-Nuclear Reactions by Means of the (p,2p) Reaction in 6Li," Phys. Rev. C24, (1981). (Exp. 156) T. C. Sharma, L. W. Swenson, K. S. Krane P. Varghese, D. K. McDaniels, H. A. Thiessen, (Exp. 268) P. O. Egan, "Muonic Helium," in Atomic N. Tanaka, R. R. Silbar, M. Greenfield, and C. F. Physics, D. Kleppner and F. M. Pipkin, Eds. (Plenum Moore, "Proton Yields from Quasielastic Pion Scattering Publishing Corp., New York, 1981). on "A1 and 208Pb," Nucl. Phys. A333, 461 (1980). (Exp. 271) D. W. Cooke and K. R. Hogstrom, "Ad- (Exp. 197) J. W. Low, E. V. Hungerford, J. C. Allred, ditivity Studies of X-Ray and Negative Pion Irradiations B. W. Mayes, L. S. Pinsky, M. L. Warneke, T. M. on the TL Response of TLD-700," Health Phys. 39, Williams, j. M. Clement, W. H. Dragoset, R. D. Felder, 568-571, (1980). J. H. Hoftiezer, J. Hudomalj-Gabitzsch, G. S. Mutchler, and G. C. Phillips, "Angular Distribution of the Reac (Exp. 271) D. W. Cooke and K. R. Hogstrom, "Ther 3 tion pd -• He7x° at 800 MeV," Phys. Rev. C23, 1656 moluminescent Response of LiF and Li2B4G7:Mn to (1981). Pions," Phys. Med. Biol. 25, 657-666, 1980. (Exp. 229/369) D. B. Holtkamp, W.J. Braithwaite, (Exp. 271) K. R. Hogstrom and H. I Amols, "Pion In- W. Cottingame, S. J. Greene, R. J. Joseph, C. F. Moore, Vivo Dosimetry Using Aluminum Activ.j ," Med. C. L. Mom- *. Piffaretti, E. R. Siciliano, H. A. Thiessen, Phys. 7, 55-60 (1980). and D. Dc/.. rd, "Isospin Mixing of 4" Particle-Hole States in 160," Ph.", Rev. Lett. 45, 420 (19' :• (Exp. 271) K. R. Hogstrom and T. Irifune, "Depth-Dose and Off-Axis Characteristics of TLD in Therapeutic (Exp. 239) D. B. Holtkamp, S.J. Seestrom-Morris, Pion Beams," Phys. Med. Biol. 25, 667-676 (1980). D. Dehnhard, H. W. Baer, C. L. Morns, S. J. Greene, 86 P*OGnE»8ATLAMPF July-December 1981 Lw Alamos National Laboratory (Exp. 271) K. R. Hogstrom, M. A. Paciotti, A. R. Smith, Los Alamos Meson Physics Facility Workshop on and M. Collier, "A Comparison of Static and Dynamic Nuclear Structure with Intermediate-Energy Probes, Los Treatment Modes for the Pion Therapy Beam at Alamos, New Mexico, January 1980; Los Alamos Scien LAMPF," Int. J. Radiat. Oncology, Biology & Physics tific Laboratory report LA-8303-C (1980), p. 33 •; Bull. 6, 1693-1700, 1980. Am. Phys. Soc. 25, 505 (1980). (Exp. 271) K. R. Hogstrom and 1.1. Rosen, "BiFusion (Exp. 310/448) C. L. Morris, H. A. Thiessen, V. J. Rates of Positron Emitters in Pion Irradiated Patients," Braithwaite, W. B. Cottingamt, S.J. Greene, D B. Phys. Med. Biol. 25, 927 932 (1980). Holtkamp, I. B. Moore, C. F. Moore, G. R. Burleson, G. S. Blanpied, G. H. Daw. and A. J. Viescas, "Observa (Exp. 310) C. L. Morris, H. A. Thiessen, W.J. tion of a Double Isobaric Analog State in the Reaction Braithwaite, S.J. Greene, I. B. Moore, W. B. Cot- 209Bi(7t+,7i-)209At," Phys. Rev. Lett 45, 1233 (1980). tingame, D. B. Holtkamp, C. F. Moore, G. R. Burleson, and G. S. Blanpied, "Mass Measurements with Pion (Exp. 310/448) S. J. Greene, G. R. Burleson, W. B. Cot Double Charge Exchange," Bull. Am. Phys. Soc. 25, 504 tingame, H. T. Fortune, D. B. Holtkamp, C. F. Moore, (1980). and C. L. Morris, "Interference Effects in Pion Double Charge Exchange," Bv'i. Am. Phys. Soc. 26, 582 (1981). (Exp. .110) S. J. Greene, W.J. Braithwaite, W. B. Cot- tingame, I. B. Moore, C. I. Harvey, D. B. Holtkamp, (Exp. 310/448) S. J. Greene, W.J. Braithwaite, D. B. C. F. Moore, C L. Morris, H. A. Thiessen, G. R. Holtkamp, W. B. Cottingame, C. F. Moore, G. R. Burleson, and G. S. Blanpied, "Pion Double Charge Ex Burleson, G. S. Blanpied, C. L. Morris, and H. A. change on 1M80 and 24>26Mg," Bull. Am. Phys. Soc. 25, Thiessen, "Systematics of (7t+,Ji") Double Charge Ex 504 (198>>). change," Proc. Int. Conf. on Nuclear Physics, Berkeley, California, August 1980 p. 687. (Exp. 310/448) S. J. Greene, "The Postive-Pion Double- Charge-Exchange Reaction: Experiments on the Isotopic (Exp. 317) R. J. Peterson, R. L. Boudrie, J. J. Kraushaar, Pairs 1M80 and ",26Mg," Los Alamos National R. A. Ristinen, J. R. Shepard, C. R. Smith, C. F. Moore, Laboratory report LA-8991-T (June 1981). W. J. Braithwaite, N. S. P. King, C. L. Morris, H. A. Thiessen, and J. Piffaretti, "Spin and Isospin Transfer in 12 + + (Exp. 310/448) S. J. Greene, W.J. Braithwaite, D. B. the C(7i ,7t ) Reaction," Phys. Rev. C21, 1030-1038 Holtkamp, W. B. Cottingame, C. F. Moore, G. R. (1980). Burleson, G. S. Blanpied, C. L. Morris, and H. A. Thiessen, "Pion Double Charge Exchange — Recent (Exp. 350) R. D. McKeown, J. P. Schiffer, H. E. Data," Proc. Los Alamos Meson Physics Facility Jackson, M. Paul, S. J. Sanders, J. R, Specht, E. J. Workshop on Nuclear Structure with Intermediate- Stephenson, R. P. Red wine, R. E. Segsl, J. Are.nds, Energy Probes, Lcs Alamcs, New Mexico, January J. Eyink, H. Hartmann, A. Hegerath, B. Metking, 1980; Los Alamos Scientific Laboratory report LA- G. Noldeke, and H. Rost, "Comparison of Pion- and 8303-C (1980), p. 430. Photon-Induced Reactions on 12C," Phys. Rev. Lett. 45, 2015 (1980). (Exp. 310) G. R. Burleson, G. S. Blanpied, G. H. Daw, A. J. Viescas, C. L. Morris, H. A. Thiessen, S. J. Greene, (Exp. 350) R. D. McKeown, S. J. Sanders, J. P. Schiffer, W. J. Braithwaite, W. B. Cottingame, D. B. Holtkamp, H. E. Jackson, M. Paul, J. R. Specht, E. J. Stephenson, I. B. Moore, and C. F. Moore, "Isospin Quintets in the R. P. Redwine, and R. E. Segel, "How Many Nucleons Ip and s-d Shells," Phys. Rev. C22, 1180 (1980). Are Involved in Pion Absorption in Nuclei?" Phys. Rev. Lett. 44, !033 (1980). (Exp. 310/448) W. J. Braithwaite, S.J. Greene, I. B. Moore, W. B. Cottingame, D. B. Holtkamp, C. F. (Exp. 354) G. S. Blanpied, G. W. Hoffmann, M. L. Moore, C. L. Morris, H. A. Thiessen, G. R. Burleson, Barlett, J. A. McGill, S.J. Greene, L.Ray, O. B and G. S. Blanpied, "Observation of the Double Isobaric van Dyck, J. Amann, and H. A. Thiessen, "Large Angle Analog State in the Reaction 209Bi(n+,7t-)2t"At," Proc. Scattering of 0.8-GeV Protons from 12C," Phys. Rev. C23, 2599 (1981). July-December 1981 PROGRESS AT LAMPF 8? Los Aiarr.vs National t aboiatory (Exp. 357) J. D. Knight, C. J. Orth, M. E. Schillaci, (Exp. 400/455) R. D. Bolton, R. D. Carlini, M.D. R.A. Naumann, F.J. Hartmann, J.J. Reidy, and Cooper, M. Duong-Van, J. S. Frank, H. S. Matis, R. E. H. Schneuwly, "Coulomb Capture Ratios of Negative Mischke, V. D. Sandberg, J. P. Sandoval, R. L. Talaga, Muons in N2 + 02, NO, and CO," Phys. Lett. 79A, 377 and D. P. Grosnick, "The Design and Performance of a (1980). Stereo Drift Chamber with Closely Packed Planes," Nucl. Instrum. Methods 188, 275-283 (1981). (Exp. 375) J. A. Brown, R. H. Heffner, R. L. Hutson, S. Kohn, M. Leon, C. E. Olsen, M. E. Schillaci, S. A. (Exp. 407) L. N. Kmetyk, J. Weertman, W. V. Green, Dodds, T. L. Estle, D. A. Vanderwater, P. M. Richards, and W. F. Sommer, "Void Growth and Swelling for O. D. McMasters, "Muon Spin Depolarization in Metals Cyclic Pulsed Radiation," J. Nucl. Mater. 98, 190-205 with Dilute Magnetic Impurities," in Proc. of the (1981); Los Alamos Scientific Laboratory report LA- Materials Research Soc. Symp. on Nuclear and Electron 8510-MS (September 1980). Resonance Spectroscopies Applied to Materials Science, Boston, Massachusetts, November 1980, Kaufmann and (Exp. 407) T. M. Cannon, D. M. Parkin, and W. F. Som Shenoy, Eds. (Elsevier North-Holland, Inc., 1981); Los mer, "Digital Enhancement and Analysis of TEM Alamos Scientific Laboratory report LA-UR-80-1504. Plates," J. Nucl. Mater. 98,329-337 (1981); Los Alamos Scientific Laboratory report LA-UR-80-3018-REV. (Exp. 375) J. A. Brown, R. H. Heffner, R. L. Hutson, S.Kohn, M.Leon, C.E. Olsen, M.E. Schillaci, S.A. (Exp. 407) O. T. Inal, and W. F. Sommer, "800-MeV Dodds, T. L. Estle, D. A. Vanderwater, P. M. Richards, Proton Damage in Tungsten and Molybdenum: A Field- and O. D. McMasters, "Muon Depolarization by Ion-Microscope Observation," J. Nucl. Mater. 99, 94-99 Paramagnetic Impurities in Nonmagnetic Metals," Phys. (1981). Rev. Lett. 47, 261 (1981). (Exp. 407) W. F. Sommer, L. N. Kmetyk, W. V. Green, (Exp. 390) S. M. Levenson, D. F. Geesaman, E.P. and R. Damjanovich, "Use of the LAMPF Accelerator Colton, R. J. Holt, H. E. Jackson, J. P. Schiffer, J. R. as a Fusion Materials-Radiation Facility," Los Alamos Specht, K. E. Stephenson, B. Zeidman, R. E. Segel, National Laboratory report LA-UR-81-2295 (1981). P. A. M. Gram, and C. A. Goulding, "Inclusive Pion Scattering in the (3,3) Resonance Region," Phys. Rev. (Exp. 407) K. E. Christensen, G. A. Bennett, and W. F. Lett. 47, 479 (1981). Sommer, "An In Situ Mechanical-Radiation Effects Test Capsule for Simulating Fusion Material Environments," (Exp. 391) B. F. Gibson, J. J. Kraushaar, T. G. Master- Los Alamos National Laboratory report LA-UR-81- son, R. J. Peterson, R. S. Raymond, R. A. Ristinen, and 2140. R. L. Boudrie, "Elastic and Inelastic JI+, n~ Scattering on 7Li," Los Alamos National Laboratory report LA-UR- (Exp. 407) L. N. Kmetyk, W. F. Sommer, and 81-347; Bull. Am. Phys. Soc. 26, 581 (1981).' J. Weertman, "The Effect of Cyclic Pulsed Temperature on Void Growth in Metals During Irradiation," Los (Exp. 400/445) G. H. Sanders, H. S. Butler, M.D. Alamos National Laboratory report LA-81-2437. Cooper, G. W. Hart, C. M. Hoffman, G. Hogan, H. S. Matis, V. D. Sandberg, R. A. Williams, E. B. Hughes, (Exp. 407) L. N. Kmetyk and W. F. Sommer, "Analytic J. Rolfe, S. Wilson, and H. Zeman, "Intelligent Trigger and Experimental Decay Heat Determinations of 800- Processor for the Crystal Box," Los Alamos National MeV Proton Irradiated Aluminum," Los Alamos Laboratory report LA-UR-81-1323. National Laboratory report LA-8946-MS (October 1981). (Exp. 400/445) G. H. Sanders, G.W. Hart, G.E. Hogan, J. S. Frank, C. M. Hoffman, H. S. Matis, and (Exp. 417) W. W. Wilcke, M. W. Johnson, W.U. V. D. Sandberg, "A High Performance Timing Dis Schroder, D. Hilscher, J. R. Birkelund, J. R. Huizenga, criminator," Nucl. Instrum. Methods 180, 603-614 J. C. Browne, and D. G. Perry, "Actinide Muonic Atom (1981). Lifetimes Deduced From Muon-Induced Fission," Phys. Rev. C21, 2019 (1980). 88 PROGRESS AT LAMPF July-December 7987 Los Alamos National Laboratory (Exp. 436) S. Takagi, H. Yasuoka, Y. Kuno, Y.J. Search for Critical Opalescence," Los Alamos Scientific Uemura, T. A. Shibata, R. S. Hayano, T. Yamazaki, Laboratory report LA-UR-80-982 (1980). Y. Ishikawa, S. E. Kohn, C. Y. Huang, and J. H. Wer- 27 nick, "|TSR and Doped A1 NMR Studies of FeSi," (Exp. 492) M. W. McNaughton, "Absolute Polarization Hyperfine Interactions 8, 499 (1981). Standards at Medium and High Energies," Los Alamos Scientific Laboratory report LA-UR-80-2395. (Exp. 436) T. Yamazaki, "Distribution of Electron Spin Densities Probed by Negative Muons," Hyperfine In (Exp. 492) M. W. McNaughton and E. P. Chamberlin, teractions 8, 463 (1981). "pp Elastic Analyzing Power from 318 to 800 MeV," Los Alamos National Laboratory report LA-UR-81- (Exp. 436) T. Yamazaki, "Basic Physics Aspects of 1705; Phys. Rev.C24, 1778 (1981). Muon Spin Research," Nucl. Phys. A335, 537 (1980). (Exp. 495) C. L. Morris, K. G. Boyer, C. F. Moore, C. J. (Exp. 452) S. J. Seestrom-Morris, D. Dehnhard, D. B. Harvey, K. J. Kallianpur, I. B. Moore, P. A. Seidl, S. J. Holtkamp, and C. L. Morris, "Identification of AS = 1 Seestrom-Morris, D. B. Holtkamp, S. J. Greene, and Transitions in l3C by Measurement of Pion Inelastic Ex W. B. Cottingame, "Pion Inelastic Scattering to Low- citation Functions," Phys. Rev. Lett. 46, 1447 (1981). Lying States in !2C and 40Ca," Phys. Rev. C24, 231 (1981). (Exp. 470/386) J. A. McGill, "Inclusive Proton Spectra and Total Reaction Cross Sections for Proton-Nucleus (Exp. 495) C. F. Moore, W. J. Braithwaite, C. J. Harvey, Scattering at 800 MeV," Los Alamos National K. Kallianpur, I. B. Moore, P. A. Seidl, D. B. Holtkamp, Laboratory report LA-8937-T (August 1981). W. B. Cottingame, S. J. Greene, and C. L. Morris, "A Comparison of Inelastic Pion Scattering from Self Con (Exp. 478) T. G. Masterson, J. J. Kraushaar, D. A. Lind, jugate Nuclei 40Ca and 12C," Bull. Am. Phys. Soc. 25, R. J. Peterson, R. S. Raymond, R. A. Ristinen, R. L. 731 (1980). Boudrie, and B. F. Gibson, "A Limit on Charge Asym metry From Elastic n-d Scattering at 143 MeV," Los (Exp. 495) C. L. Morris, R. L. Boudrie, J. Piffaretti, C. J. Alamos National Laboratory report LA-UR-81-993 Harvey, C. F. Moore, P. A. Seidl, W. B. Cottingame, (1981). S. J. Greene, S. J. Seestrom-Morris, and D. B. Holtkamp, "Isospin Purity of the Giant Dipole Resonance in l2C," (Exp. 478) T. G. Masterson, B. F. Gibson, J.J. Bull. Am. Phys. Soc. 26, 536 (1981). Kraushaar, R. J. Peterson, R. S. Raymond, R. A. Ristinen, and R. L. Boudrie, "Test of Hardonic Charge (Exp. 495) D. B. Holtkamp, C. L. Morris, W. B. Cot- Symmetry by Pion Scattering on Deuterium," Phys. tinga.ne, S. J. Greene, W. J. Braithwaite, C. J. Harvey, Rev. Lett. 47, 220 (1981). C. F. Moore, I. B. Moore, and P. A. Siedl, "A Study of the I+ States of ]2C with Pion Inelastic Scattering: (Exp. 486) M. Haji-Saeid, C. Glashausser, G. Igo, Angular Distributions and Excitation Functions," Bull. W. Cornelius, M. Gazzaly, F. Irom, J. McClelland, J. M. Am. Phys. Soc. 25, 730 (1980). Moss, G. Pauletta, H. A. Thiessen, and C. A. Whitten, Jr., "Inelastic Proton Scattering at 800 MeV to the 12C (Exp, 499) M. Leon, "Models for Muon Plus Depolariza 15.11-MeV State: A Search for Nuclear Critical tion in Spin Glasses for Zero External Field," Los Opalescence," Phys. Rev. Lett. 45, 880 (1980). Alamos Scientific Laboratory report LA-UR-2371 (1980); Hyperfine Interactions 8, 781 (1981). (Exp. 486) C. Glashausser, S. M. Haji-Saeid, G. J. Igo, J. B. McClelland, J. M. Moss, W. D. Cornelius, M. Gaz (Exp. 499) D. E. MacLaughlin, "Muon Spin Rotation zaly, F. Irom, G. Pauletta, H. A. Thiessen, and C. A. and Other Microscopic Probes of Spin-Glass Whitten, "800-MeV Proton Inelastic Scattering to the Dynamics," Los Alamos Scientific Laboratory report 12 C 15.11 MeV State at Large Momentum Transfer: A LA-UR-2372 (1980); Hyperfine Interactions 8, 749 (1981). July-December 19B1 PROGRESS AT LAMPF 89 Los Alamos National Laboratory (Exp. 499) J. A. Brown, R. H. Heffner, T. A. Kitchens, (Exp. 553) L. C. Liu, "Two-Nucleon Processes in a M. Leon, C. E. Olsen, M. E. Schillaci, S. A. Dodds, and Coupled-Channel Approach to Pion-Nucleus Single- D. E. MacLaughlin, "Anomalous Paramagnetic-State Charge-Exchange Reactions," Phys. Rev. C23, 814- Muon Spin Rotation in Spin-Glass Ag:Mn," J. Appl. 827 (1981). Phys. 52, 1766 (1981). (Exp. 562) D. Ashery, R. J. Holt, H. E. Jackson, J. P. (Exp. 499) J. A. Brown, S. A. Dodds, T. L. Estle, R. H. Schiffer, J. R. Specht, K. E. Stephenson, R. D. Heffner, M. Leon, D. E. MacLaughlin, C. E. Olsen, and McKeown, J. Ungar, R. E. Segel, and P. Zupranski, M. E. Schillaci, "Zero and Finite Field Muon Spin Rota "Isospin Dependence of Pion Absorption on a Pair of tion in Spin-Glass Ag:Mn," Los Alamos Scientific Nucleons," Phys. Rev. Lett. 47, 895 (1981). Laboratory report LA-UR-80-1563 (1980); Hyperfine Interactions 8, 763 (1981). (Exp. 571) M. E. Schillaci, R. L. Hutson, R. H. Heffner, S. A. Dodds, M. Leon, and T. L. Estle, "Depolarization (Exp. 519) S. Frankel and W. Frati, "Mechanism for of Diffusing Spins by Paramagnetic Impurities," Hyper Backward Production of High-Energy Protons in p- fine Reactions 8, 663 (1981); Los Alamos Scientific Nucleus Collisions," Phys. Rev. C24, (1981). Laboratory reports LA-UR-80-1503 and LA-UR-80- 2376 (1980). (Exp. 519) H. Brody, S. Frankel, W. Frati, and O. B. van Dyck, "Elastic and Inclusive Analyzing Power of (Exp. 571) R. H. Heffner, "Muon Spin Depolarization in Deuterium for 0.8-GeV Protons," Phys. Rev. C24, Nonmagnetic Metals Doped with Paramagnetic Im (1981). purities," Hyperfine Interactions 8, 655 (1981); Los Alamos Scientific Laboratory report LA-UR-80-2375 (Exp. 539) C. J. Harvey, H. W. Baer, C. L. Morris, D. B. (1980). Holtkamp, S. J. Seestrom-Morris, D. Dehnhard, and S. J. Greene, "A Study of the Neutron Density Distribu (Exp. 580) R. L. Boudrie, J. F. Amann, G. C. Idzorek, 12 13 14 + tions of - ' C from a Comparison of n and n~ Elastic S. J. Seestrom-Morris, D. B. Holtkamp, M. A. Franey, Scattering," Bull. Am. Phys. Soc. 26, 582 (1981). D. Dehnhard, and C. Goulding, "Scattering of 547 MeV Polarized Protons from 13C," Bull. Am. Phys. Soc. 26, (Exp. 539) D. B. Holtkamp, S.J. Seestrom-Morris, 582 (1981). D. Dehnhard, H. W. Baer, C. L. Morris, S.J. Greene, and C. J. Harvey, "Strong Cancellations of Neutron and (Exp. 629) W. L. Talbert, Jr., M. E. Bunker, B.J. Proton Transitions Amplitudes Observed in Pion In Dropesky, J. W. Starner, R. C. Greenwood, R. J. elastic Scattering from ,4C," Bull. Am. Phys. Soc. 26, Gehrke, and V. J. No^'ick, "Transport of Fission and 582 (1981). Spallation Products bv He-Jet," Bull. Am. Phys. Soc. 26, 1156 (1981). 90 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory IV. FACILITY AND EXPERIMENTAL DEVELOPMENT Research Support at LAMPF (Second in a Series) Keeping the mechanical, electrical, and hydraulic Ring upon its completion. Development activities are systems of the LAMPF accelerator in operation, and almost continuous in all of the activities shown in Fig. 1. designing and implementing upgrades of equipment are Beam availability currently approaches a remarkable the functions of the Accelerator Support Group, MP-11. 90% as compared to the design figure of 75%. Much of These activities span the accelerator space from ion the credit for this high performance goes to members of sources and injectors to power and water supplies for MP-11, who are, by turns, on call during machine opera magnets in experimental areas. Figure 1 shows tion. When the machine suffers unscheduled outages, schematically the locations of the group's activities. MP-11 is on the job to restore operation. One current major project is an ion source which will Figures 2-8 show some of the activities of the Ac provide high-current H~ capability to the WNR Storage celerator Support Group. Q/& -!-—E 3= i 201 MHz SYSTEM 805 MHz SYSTEMS •-fl-Q ION/SOURCE DEVELOPMENT POLARIZED INJECTOR INJECTOR SYSTEMS POWER SUPPLIES WATER SYSTEMS - VACUUM SYSTEMS BEAM DIAGNOSTICS - RF PHASE AND AMPLITUDE CONTROL SYSTEMS MASTER FREQUENCY CONTROL AND DRIVE LINES • OTHER SUPPORT GROUPS ELECTRONIC INSTRUMENTATION AND COMPUTER SYSTEMS-MP-I ACCELERATOR 0PERATI0NS-MP-2 EXPERIMENTAL AREAS-MP-7 ENGINEERING SUPP0RT-MP-8 BEAM LINE DEVELOPMENT- MP-13 Fig. 1. Accelerator support, MP-11. July-December 1981 PROGRESS AT LAMPF 91 Los Alamos National Laboratory Fig. 2. Bobby Poe (above) and Allen Herring perform a residual gas analysis on 201-MHz tank. Fig. 3. Bill Boedeker inspects beam boxes. 92 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Fig. 5. Don Rader wires a sample-and-hold chassis for emittance-measuring apparatus. Fig. 4. Bill Halloran machines parts for the intense H~ source that is under development. Fig. 6. The 805-MHz rfcrew. Left to right: Don Patton, Chester Higgins, Bob Newell, David Trudell, and Don Rader. July-December 1981 PROGRESS AT LAMPF 93 Los Alamos National Laboratory Fig. 7. Harry Williams, Phil Chamberlin, and Rob York (top to bottom) inspect the polarized ion source. Fig. 8. Joe Primeaux wires a LAMPF standard module. 94 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory The LAMPF Radiation Effects Facility — A New Stringer Introduction The radiation-effects facility (REF) at LAMPF was built to allow study of radiation damage produced by spallation neutrons, which are generated by the main proton beam in the isotope production targets and the copper beam stop. Access to the neutron flux is via three stringers that penetrate 8 m of shielding around the beam stop. Previous stringers allowed insertion of samples hav ing diameters to 50 mm, but sample lengths were restric ted because of bends in the tubing required to reduce radiation streaming. In addition, samples had to be inser ted and removed in the pit region, access to which re quired a lengthy machine shutdown for personnel safety. To overcome these problems, a stringer design was sought that would allow samples to be inserted and removed from outside the isotope production facility building and that would increase the available sample volume. .__ * J^ ^ Fig. I. Stringer Design (a) Sample cart positioned to irradiation position. (b) As above but shield door raised, (c) View shows To allow easy sample insertion and removal, we guide tube extended across the pit as the cart is decided on the concept of a wheeled cart pulled through withdrawn, (d) Guide tube has been pulled outside a rectangular tube by a come-along. A disposable sample the building with cart in position for transfer of box (inside dimensions are 295 mm long, 73 mm wide, samples to cart, (e) Sample cart. and 50 mm deep) was designed to slip inside the cart. Provision has been made for instrumentation wiring be tween the samples and the outside. During irradiation, Operation — Neutron Spectrum the sample box is cooled by contact with a water-cooled copper plate. The new stringer was placed in operation during To reduce the radiation streaming through the rec Cycle 30. The initial runs were used to study the neutron tangular tube, it was necessary to place a movable shield flux vs energy and position in the sample box, with the block between the pit and the neutron source. The con results shown in Fig. 2. It should be noted that the straints imposed by the stringer housing dictated the use neutron spectrum and flux will vary with the type and of a vertically moving shield block, which in its upper location of the isotope production targets. It has position covers the rectangular tube opening and, when previously been suggested1 that the spallation neutron down, allows the cart to ride on its top surface while be spectrum available at the REF is suitable for studying (at ing inserted or withdrawn. The shield block is 1.8 m long, low fluence) radiation damage produced by neutrons at and is raised and lowered by end wedges moved by a fusion reactors. Samples have already been irradiated in motor-driven lead screw. The shield block's vertical posi the new stringer in conjunction with Exp. 545, "Fusion tion is monitored by microswitches interlocked with the Materials Neutron Irradiations." Several runs have been radiation safety system, which allows the proton beam to instrumented, indicating peak sample temperatures of be on only if the block is in the raised position. Operation 140°C. of the stringer is illustrated in Fig. 1. July-December 1981 PROGRESS AT LAMPF 95 Los Alamos National Laboratory the container at Oak Ridge at atmospheric pressure and used under vacuum at EPICS. To prevent distortion of the container and possible shifting of the carbon powder, provision had to be made to permit the internal pressure to reach environmental pressure (atmospheric or vacuum). The target holder was made as a frame wrapped with 1 mil (25 urn) stainless steel foil, as shown in Fig. 1. One narrow end is plugged with a porous filter to permit passage of gas; the filter is sintered stainless steel. The components were assembled with a polyurethane adhesive. Tests showed that the pressure change should be less than 1/2 psi per minute to prevent stretching of the window foil. LO 10 100 The filling and shipping operation required fabrication NEUTRON ENERGY (M«V) of containers for shielding and protection against rapid pressure changes, and to protect the foil while loading J4 Fig. 2. the C. The filled targets as received at LAMPF re The variation in neutron spectrum between the quired decontamination but were otherwise generally in front location (~300 mm from the beam line) and satisfactory shape. Six targets were selected and moun the back location (~533 mm from the beam line) in ted on a holder for the target ladder at EPICS. At the 14 the new REF stringer sample box. conclusion of the experiment, no C leakage was found. Thin-walled vessels for tritium gas targets pose ad ditional challenges of greater radiation hazard and pressure containment. The latter requirement constrains Acknowledgment the vessel geometry to spherical if wall thickness is to be We would like to thank J. E. Vasquez for his design con tributions. REFERENCE 1. M. L. Simmons and D.J. Dudziak, "Controlled Thermonuclear Reactor Neutron Spectra Simulation at the LAMPF Radiation Ef fects Facility," Nucl. Technol. 29, 337 (1976). —R. D. Brown and C. F. Hansen Special Target Holders It is a common enough challenge in nuclear physics to fabricate pure isotopic targets with a minimum of wall material. Recently, two special challenges were met: a vessel to hold powdered 14C in vacuum, and a high- pressure gas target. We describe both targets here to il lustrate the special engineering services available to ex perimenters at LAMPF. Fig.l. The '4C target dimensions are 30 by 72 by 3 mm. The Carbon-14 target holder parts: frame, cup formed material is similar to lampblack and would be loaded in from foil, and sintered plug, all stainless steel. 96 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory minimized. Five-inch-diam (127-mm) hemispheres of stainless steel with 0.62-mm wall thickness, and aluminum with 0.8-mm wall thickness, were found com mercially available. The attempt to use aluminum spheres was dropped at a later stage. A technique to assemble the spheres evolved through trial and error and under safety constraints to ensure adequate strength and reliability. The hemispheres were machined to have matching lip-and-groove at the equator, then welded. The welded spheres were annealed and radiographed, and the voids repaired. The best five spheres were selected for targets; the remainder were used for testing. A laboratory safety committee set forth assembly and testing methods to ensure safety. The permitted working presure would be the lower of 200 psia or 1/3 yield; the yield pressure would be determined using four spheres. Each sphere selected for use as a target would be copper plated and tested at 400 psia or 2 times working pressure. The spheres destined to hold tritium would be gold plated to prevent tritium diffusion. Finally, material analysis would be required. An assembled sphere is shown in Fig. 2 before finishing and plating to show the equatorial electron-beam weld. Fig. 2. Tne yield and ultimate pressure tests, conducted by Tritium target sphere [5 in. diam (127 mm)], wall Laboratory group WX-11, showed that the yield thickness 0.62 mm, with mounting post on one end pressure exceeded 660 psi and ultimate pressures of and threaded fill tube on the other end. 1500-2500 psi. Material analysis from the supplier of the hemispheres was accepted. Eight Laboratory groups in H, MP, MEC, CMB, WX, and M Divisions were in the magnetron sources at the Fermi National Ac volved in target fabrication, filling, and handling. celerator Laboratory and at the Brookhaven National —/. Van Dyke Laboratory. These sources have adequate peak current, but are presently limited to low duty factor operation. A different approach is needed to provide an adequate H~ Ion Source Program quality source for the proton storage ring, and it is necessary for LAMPF to undertake a development program to provide such a source. Introduction Fortunately, high-current H~ sources have recently The requirement for high-intensity H~ ion beams for been developed in the Lawrence Berkeley Laboratory fu the WNR Proton Storage Ring has necessitated the sion program to provide intense neutral-beam injection. development of a new H" ion source. The present H~ ion Additional development required for the accelerator ap source at LAMPF is a charge exchange source and is plication is in the area of high-voltage extraction of high- limited to low-intensity operation. Although the develop brightness beams. A similar development program has ment of a higher intensity charge exchange source is cer been carried out at LAMPF in improving the brightness tainly possible, such a source would have fundamental of the proton beams from the LAMPF duoplasmatron. It limitations on beam brightness and would be marginal at was decided to develop a scaled down version of a best for LAMPF operations. Various types of direct- suitable neutral-beam injector ion source to provide a extraction H~ ion sources have been developed in the relatively low-current but high-brightness beam. The in past few years for other accelerator applications, such as itial goal of this program is to obtain an ion source that will produce H~ beams with the same intensity and beam July-December 1981 PROGRESS AT LAMPF 97 Los Alamos National Laboratory quality as the H+ beams now used for production at voltage extraction system to the desired operating poten LAMPF. tial. For these beams to be useful in an accelerator ap plication, the extraction system must suppress the high electron flux with a minimum distortion of the H" beam. Ion-Source Concept A static dipole magnetic field and a biased-exit electrode, termed a plasma-repeller electrode, are used to effect this The ion-source concept most closely meeting our re electron suppression. The development of these concepts quirements is the self focused, cusped-field source is now being pursued both at Berkeley and Los Alamos developed at Berkeley by Ehlers and Leung.' A and is expected to produce an accelerator-quality H" ion schematic diagram of our prototype based on the source. Berkeley concept is shown in Fig. 1. A cusped-field magnetic bucket is used for confinement of a low-density Experimental Program hydrogen plasma. A converter electrode in the form of a spherical cap is immersed in this plasma and biased An experimental program was undertaken at LAMPF several hundred volts below plasma potential. The to demonstrate the feasibility of using this ion source production of H~ ions is effected at the surface of the concept for the proton storage ring. A small cusped-field converter electrode mainly by desorption of hydrogen ion source and a ground-level test stand, which had been atoms by positive ion bombardment. These H~ ions are previously used in the development of intense H+ ion self-focused by the spherical plasma sheath at the con beams, were obtained. The ion source was modified to verter surface into a converging beam. This beam accept a converter electrode, a standard duoplasmatron propagates through the plasma to an exit aperture in the beam-extraction system, and a plasma-repeller electrode. magnetic bucket and is then accelerated by a high- The aperture in the plasma-repeller electrode, together VACUUM GAUGING DIPOLE MAGNETS CUSPED FIELD MAGNETS FILAMENT ASSEMILV WATER COOLING LINES PLASMA REPE1XER ELECTRODE ADAPTER PLATE PIERCE ELECTRODE EXTRACTOR ELECTRODE 1—ACCELERATING COLUMN fig. J. Prototype cusped-field H~ ion source. 98 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory with the size of the converter, was chosen to produce a beam current that could be obtained from the source. small-emittance ion beam, a choice that subsequently has Nevertheless, H~ beams up to 4 mAp at 10% duty factor been found to be too restrictive for optimum operation. were successfully extracted and transported to the emit Nevertheless, these modifications and design choices did tance scanners. Emittance measurements taken with the permit a low-current prototype source to be built. scanners (see Fig. 2) confirmed that the emittance of The ground-level test stand was refurbished and the these beams is indeed within the designed geometrical ad necessary modifications were made to test the prototype mittance of the prototype ion source. Stable, quiet opera H~ ion source. The ion source produced an 8-mA-dc tion of this source was achieved in these first tests. beam of H~ ions at 200 eV, which was the current expec ted for this prototype design. The source was then moun ted on a high-voltage test stand and H~ beams were ex Experimental Results tracted at energies up to 100 kV. These beams were momentum analyzed and emittance data taken with a The initial results obtained with this first prototype ion standard LAMPF emittance-scanning system. In the in source demonstrate the feasibility of using an H~ cusp- itial high-voltage tests, problems were encountered in ob field type ion source for accelerator applications. High- taining proper cooling to the accelerating structures on quality beams at 100 kV of 4 mAp were obtained and the test stand. This constraint limited the arc power that further tests with a cooled version of this design are ex could be safely run in the ion source and thus the H" pected to yield beam currents up to 8 mAp. The emit tance of the extracted beam can indeed be defined by the geometrical admittance of the ion source, which was 0.08 cm-mrad (normalized*) in these first tests. The H~ "O beam fraction is typically 95% of the total extracted ion O beam. Election loading was small as evidenced by current drain on the high-voltage power supply but cer LU tainly was not coirroletely eliminated since there was O significant x-ray production. The rise time of the extrac UJ ted H~ beams was several microseconds. No other a rr significant transients in beam current were observed with u unanalyzed beam. Voltage modulation of the converter > 0 electrode permitted rapid (several microseconds) current modulation of the extracted beam. We expect that further development of this self-focusing, cusped-field type of ion source will result in an ion source that will O produce the desired beam currents for the proton- N storage-ring application with the high brightness required for high-duty accelerator operation. REFERENCE HORIZONTAL POSITION (cm) 1. K. W. Ehlers and K.N. Leung, "Characteristics of a Self- Extraction Negative Ion Source," Lawrence Berkeley Laboratory report 11637. Fig. 2. Horizontal emittance distribution for a 4 mAp H~ ion beam. 'Normalized = multiplied by Lorentz factor ((3y = p/m). —R. R. Stevens, Jr. July-December 1981 PROGRESS AT LAMPF 99 Los Alamos National Laboratory V. ACCELERATOR OPERATIONS This report covers operating Cycles 30, 31, and 32. because it impairs the beam transmission interlock The accelerator was in operation from early July through system which serves to protect beam-line components in late November, providing beams for research use for 111 that region. Average H+ beam current was limited to days and for facility development for 13 days. A sum 500 nA during Cycle 32 because of large cooling-water mary of information on beams provided for experimental leaks in the A6 beam stop shielding. A summary of un use is given in Table I. scheduled facility downtime during research shifts is Machine operation continued to be reliable and stable. given in Table II. Because some of the outages were con A new A-t solution, with reduced power settings for most current, the total is greater than the beam downtime. of the 805-MHz klystrons, was used successfully. Ap Accelerator development efforts addressed dual-beam proximately 1/4 MW was saved in total power consump steering problems associated with future operation of the tion; in addition, klystron lifetimes may be extended. Proton Storage Ring. The work concentrated on improv Significant degradation in beam-current-monitor ing computer modeling capability and on detection and toroids and beam profile monitors at A5 and A6 was ob replacement of several suspect quadrupole magnets. served. The toroid damage is especially worrisome —J. Bergstein TABLE I BEAM STATISTICS FOR CYCLES 30, 31, AND 32 Cycle 30 Cycle 31 Cycle 32 No. of experiments served 40 28 34 H+ scheduled beam hours 898 815 837 H~ scheduled beam hours 148 - - P~ scheduled beam hours 710 791 829 H+ beam availability, % 86 89 90 H~ beam availability, % 84 - - P" beam availability, • % 79 82 85 H+ average current, uA 565 535 500 H~ average current, uA 3 ... ~ P~ average current, nA ~5 ~5 ~5 H+ beam duty factor, % 6-7.5 6-7.5 6-7.5 H~, P~ beam duty factor, % 3-7.5 3-7.5 3-7.5 100 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory TABLE II UNSCHEDULED MACHINE DOWNTIME Category Downtime (h) Percent of Total 201-MHz amplifiers and transmission lines 50 11 805-MHz amplifier systems 35 8 Vacuum 25 6 Magnets and magnet power supplies 42 10 Interlocks 15 3 Injectors 135 30 Water 78 17 Computer control and data acquisition 16 4 Beam stops, plugs, targets, strippers, scrapers 32 7 Miscellaneous (utilities, etc.) 17 4 TOTAL 445 July-December 1981 PROGRESS AT LAMPF 101 Los Alamos National Laboratory CLINTON P. ANDERSON MESON PHYSICS FACILITY MILESTONES Official Ground Breaking February 15, 1968 Spinoff: Adoption of LAMPF Accelerating Structure for X-Ray Therapy and Radiography Machines ca 1968 5-MeV Beam Achieved June 10, 1970 Adoption of a LAMPF Standard Data-Acquisition System August 1970 100-MeV Beam Achieved June 21, 1971 211-MeV Beam Achieved August 27, 1971 800-MeV Beam Achieved June 9, 1972 Spinoff: First Use of Electrosurgical Forceps in Open-Heart Surgery (University of New Mexico) September 13, 1972 Discovery of 23frTh (Experiment Zero) September 25, 1972 Dedication to Senator Clinton P. Anderson September 29, 1972 Spinoff: First Hyperthermic Treatment of Animal Tumors October 1972 First H~ Injector Beam March 28, 1973 First Simultaneous H+ and H~ Beams May 4, 1973 Beam to Area B July 15, 1973 First Experiment (#'>6) Received Beam August 24, 1973 First Meson Production, Beam to Area A August 26, 1973 Beam to Area A-East February 6, 1974 First Medical Radioisotope Shipment July 30, 1974 Usable 100-uA Beam to Switchyard September 5, 1974 Pi-Mesic Atoms with "Ticklish" Nuclei October 13, 1974 First Experimental Pion Radiotherapy October 21, 1974 First Tritium Experiment (80 000 Ci) November 1974 Start of Great Shutdown December 24,1974 New Precise Measurements of Muonium Hyperfine Structure Interval and u+ Magnetic Moment 1975-77-80 Q Data-Acquisition Software Operational June 1975 Spinoff: First Use of 82Rb for Myocardial Imaging in Humans (Donner Laboratory, Lawrence Berkeley Laboratory) June 1975 Spinoff: First Hyperthermic Treatment of Human Cancer (University of New Mexico) July 11, 1975 Accelerator Turn On Starts August 1, 1975 Acceptable Simultaneous 100-uA H+ and 3-uA H" Beams to Switchyard September 14, 1975 Production Beam to Area B October 7, 1975 First Pions Through EPICS Channel March 18, 1976 Production Beam in Area A and Area A-East: End of Great Shutdown April 5, 1976 Muon Spin Rotation Program June 1976 Spinoff: First Hyperthermic Treatment of "Cancer Eye" in Cattle (Jicarilla Reservation) June 3, 1976 100-uA Production Beam in Area A August 1976 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory MILESTONES (Continued) Experiment in Atomic Physics (H~ + laser beam): Observation of Feshbach and Shape Resonances in H~ October 1976 Double Charge Exchange in l60: LEP Channel October 5, 1976 Startup of Isotope Production Facility October 15, 1976 HRS Operation Begins November 1976 Maintenance by "Monitor" System of Remote Handling Fall 1976 Proton Beam to WNR March 12, 1977 Polarized Proton Beam Available April 1977 Spinoff: First Practical Applications Patent Licensed to Private Industry April 12, 1977 Pion Radiotherapy with Curative Intent May 1977 Proton Computed Tomography Program June 1977 Experimental Results at Neutrino Facility July 1977 Cloud and Surface Muon Beams: SMC Channel July 1977 EPICS Operation Begins August 1977 300-uA Production Beam in Area A Fall 1977 AT Division Established January 1, 1978 7i° Spectrometer Begins Operation February 1978 Operation of Polarized Proton Target Spring 1978 Successful Water-Cooled Graphite Production Target November 1978 Spinoff: First Thermal Modification of Human Cornea (University of Oklahoma) July 11, 1979 600-uA Production Beam in Area A November 1979 New Limit on u —*• ey December 1979 Commercial Production of Radioisotopes January 1980 Spin Precessor Begins Operation February 1980 Data-Analysis Center Operational April 1980 Variable-Energy Operation June 1980 Single Isobaric Analog States in Heavy Nuclei June 1980 Spinoff: First Use of 82Rb for Brain Tumor Imaging in Humans (Donner Laboratory, Lawrence Berkeley Laboratory) September 1980 Double Isobaric Analog States in Heavy Nuclei October 1980 Focal Plane Polarimeter Operational at HRS October 1980 Safety Award to LAMPF Users Group, Inc., for Working One Million Man-Hours Since 1975 Without a Disabling Injury October 27, 1980 New Measurement of Pion Beta Decay — Improved Test of Conserved Vector Current November 1980 July-December 1981 PROGRESS AT LAMPF 103 Los Alamos National Laboratory APPENDIX A EXPERIMENTS RUN Exp. Beam No. Experiment Title Channel Hours 67 Development of Pion Beam-Monitoring 6.3 Techniques 106 Proton-Induced Spallation Reactions Related AB-Nucchem 0.0 to the Isotope Production Program at LAMPF 123 Nuclear Structure Effects in Pion-lnduced 6.5 Nuclear Reactions 14.5 225 A Study of Neutrino-Electron Elastic Neutrino Area 47.0 Scattering 249 The (p,n+) Reaction on "He with HRS 97.0 800-MeV Protons 267 Preparation of Radioisotopes for Medicine and the ISO RAD 764.0 Physical Services Using the LAMPF Isotope 578.0 Production Facility 694.6 270 Therapy Beam Development — Biomedical Channel Biomed 70.0 Tuning 68.0 271 Therapy Beam Development — Dosimetry Biomed 132.0 78.7 97.0 272 Therapy Beam Development — Microdosimetry Biomed 15.0 274 Pion Radiobiology Biomed 155.0 235.0 275 Pion Clinical Trials Biomed 350.0 293.0 351.7 294 High-Energy Nuclear Reactions AB-Nucchem 2.0 303 A Survey of Pion S'ngle-Charge-Exchange LEP 304.0 Scattering Using Back-Angle Gamma Spectroscopy 308 An Attempt to Make Direct Atomic-Mass Thin Target Area 508.9 Measurements in the Thin Target Area 309 Inclusive n+ and ir Double Charge Exchange P3 353.0 on 160 and 40Ca 241.0 315 High-Resolution Study of the (n+,2p) Reaction LEP 629.0 349 Nuclear Reactions of '"I with Pions AB-Nucchem 3.6 104 PROGRESSATLAMPF July-December 1981 Los Alamos National Laboratory Exp. Beam No. Experiment Title Channel Hours 356 Analyzing Power and Cross-Section Measurements HRS 88.1 for Inelastic Proton Excitation of Simple States 369 Inelastic Pion Scattering by "O, '"0, and ,9F EPICS 274.0 386 Total Reaction Cross Sections for P+ Nuclei HRS 30.0 at 800 MeV HRS 118.2 392 A Measurement of the Triple-Scattering HRS 187.0 Parameters D, R, A, R' and A' for Proton-Proton and Proton-Neutron Scattering at 800 MeV 399 Excitation of Giant Multipole Resonances by HRS 40.0 200-400-MeV Protons 400 Search for the Rare-Decay M+ — e+e+e_ SMC 225.0 60.9 411 Measurement of Spin-Flip Probabilities in HRS 47.0 Proton Inelastic Scattering at 800 MeV and Search for Collective Spin-Flip Modes (Preliminary Survey) 416 Study of Fast Pion-lnduced Fission of Uranium P* 15.2 427 Magnet Resonance Studies of M+Electron-Defect SMC 21.0 Complexes in Nonmetals 449 Survey of Single and Double Photodetachment EPB 116.3 Cross Section of the H- Ion from 14-21.8 eV 455 High-Precision Study of the u+Decay P3 138.0 Spectrum 124.0 159.3 465 Radiochemical Study of Pion Single Charge LEP 24.0 Exchange P3 12.0 45.7 476 The Analyzing Power for p + 2428Mg HRS 64.7 at 500 and 800 MeV 484 Inelastic Pion Scattering from 148Sm and '52Sm EPICS 70.7 491 Experimental Determination of the Strong- SMC 141.1 Interaction Shift In the 2p-1s Transition of Plonic Deuterium and Hydrogen Atoms 499 Muon Longitudinal and Transverse Relaxation SMC 54.0 Studies in Spin-Glass Systems 72.0 508 Dibaryon Resonances in Pion Production HRS 171.0 512 Proton-Proton Elastic-Scattering Measurements EPB 311.0 of the Ass(e), ALl(e), and Asl(e) 524.0 Spin-Correlation Parameters at 500, 650, and 800 MeV July-December 1981 PROGRESS AT LAMPF 105 Los Alamos National Laboratory Exp. Beam No. Experiment Title Channel Hours 517 Polarized Beam and Target Experiments in Area B 428.0 the p-p System. Phase 1. AY and A„ 414.0 + for the dn Channel and AY¥ for the 452.9 Elastic Channel from 500-800 MeV 520 Study of the Reaction p(Polarized) + HRS 127.0 (34He) - (p,d,n..) + X to Measure the Analyzing Power Structure Functions for Backward Particles 538 Analyzing Power and Cross-Section HRS 43.0 Measurements of the 4He(p,d)3He Reaction 541 A Search for Nuclear Critical Opalescence LEP 773.7 Using the Reaction "Ca(n+,2y) 543 A Product Recoil Study of the (n^N) P3 63.0 Reaction 8.5 544 Search for a Fast Fission Process LEP 76.0 545 Fusion Materials Neutron Irradiations — Radiation Damage 41.8 A Parasite Experiment 183.0 546 Investigation of the Spin Form Factor of EPICS 240.0 Tritium and 3He 547 Search for Fast Muonium in Vacuum SMC 100.1 553 Study of Target Thickness Effects in the Cross- P3 23.5 Section Measurement of the Pion Single-Charge- LEP 14.0 Exchange Reaction ,3C(n+,n°)"N(g.s.) P3 14.0 from 50-350 MeV 561 n* Nuclear Elastic Scattering at LEP 241.0 Energies Between 30 and 80 MeV 563 P + p Elastic Scattering at 600 and HRS 76.3 500 MeV 564 Study of Small-Angle 4He(n-,n+) 435.5 Reaction 571 Muon-Spin-Rotation Studies of Dilute SMC 84.0 Magnetic Alloys 12.0 577 Measurement of Angular Distributions EPICS 237.0 for 1<,0(n+,n-)1«Ne 585 Measurement of p-p and p-d Elastic Scattering HRS 106.0 in the Coulomb Interference Region Between 500 and 800 MeV 591 An Investigation of Inclusive One-Pion EPB 159.0 Production in Proton-Nucleus Collisions 492.1 106 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Exp. Beam No. Experiment Title Channel Hours 594 Precision Determinations of Some Relative SMC 93.0 Muonic Coulomb Capture Ratios in Oxides of Different Valences 595 An On-Line Gamma-Ray Study of Pion- 15.2 Induced Single-Nucleon Removal Reactions on "C and 48Ca 597 The Study of Broad-Range Pion Inelastic- EPICS 135.0 Scattering Spectra (with Emphasis on the Excitation of the Giant Monopole Resonance) 603 Search for Deltas in a Complex Nucleus Area B 13.5 by a Radiochemical Technique 606 Tests of the (N - Z) Dependence of Pion EPICS 431.0 Double Charge Exchange 611 Excitation Functions of the Four P3 8.5 ""Te^.n'N) Reactions 616 Measurement of the Wolfenstein Parameters HRS 237.4 for the 1+ States of ,!C 617 A Study of the (3/2,3/2) Resonance in EPICS 158.0 Light Nuclei 619 Inelastic Pion Scattering to 0+ and 2+ States EPICS 136.6 in 40Ca and 42Ca 622 Investigation of the Strong Cancellations EPICS 138.1 of Neutron-Proton Transition Amplitudes in "C 625 Inelastic Scattering of Pions to Giant EPICS 162.0 Resonances 627 Measurement of the Relative Sign of HRS 64.0 Neutron and Proton Transition Matrix Elements in (p,p') Reactions 629 Feasibility of Helium-Jet Techniques for AB-Nucchem 24.0 Studying Short-Lived Nuclei Produced at LAMPF 630 A Study of Proton Inelastic Scattering at HRS 59.0 0° and a Search for Giant Monopole and Giant Magnetic Dipole Excitations 634 Measurement of Parity Violation in the EPB 113.2 p-Nucleus Total Cross Sections at 800 MeV 144.0 639 Muon-Spin-Rotation Study of Muon Bonding SMC 24.0 and Motion in Select Magnetic Oxides July-December 1981 PROGRESS AT LAMPF Los Alamos National Laboratory Exp. Beam No. Experiment Title Channel Hours 640 Transverse and Longitudinal Field MSR SMC 69.0 Measurements In Selected Ternary Metallic 114.0 Compounds 642 Reactive Content of the Optical Potential — HRS 46.3 Phase II 643 Structure of States in the Oxygen HRS 20.0 Isotopes via Measurements of the Spin HRS 80.0 Depolarization and Spin Rotation Observables 646 Hyperfine Structure of Muonic 3He and SMC 120.0 Muonic 4He Atoms 294.0 653 The M,Am and 2«Am Muonic Atom Studies SMC 151.1 108 raOOREUATLAMPF July-December 1981 Lot Alamos National Laboratory APPENDIX B NEW PROPOSALS Proposal No. Title Spokoenwn Institution 697 Nuclear Excitation Following Muon B. Budick New York Univ. Capture on Medium and Heavy Nuclei 698 Ground-State Quadrupole Moments R. M. Steffen Purdue Univ. of Deformed Nuclei E. B. Shera Los Alamos 699 Measurements of Spin Flip and N. M. Hintz Univ. of Minnesota Depolarization Parameters for 58Ni(p,p')6,Ni* (6\T = 0) — a Test of the Spin-Orbit Force in Nuclei at 500 MeV 700 Double Charge Exchange on 40Ar H. T. Fortune Univ. of Pennsylvania C. L. Morris Los Alamos 701 Pion Double Charge Exchange on C. L. Morris Los Alamos Self-Conjugate Nuclei H. T. F-rtune Univ. of Pennsylvania 702 Nuclear Structure Effects in Pion J. R. Comfort Arizona State Univ. Scattering from 92-'°°Mo 703 Study of M4 Strength in 15N by D. B. Holtkamp Univ. of Minnesota n+ and IT Inelastic Scattering S. Seestrom-Morris Los Alamos 704 Pion Inelastic Scattering From 20Ne C. F. Moore Univ. of Texas H. T. Fortune Univ. of Pennsylvania 705 Study of Pion Absorption in 3He On D. Ashery Tel Aviv Univ., Israel and Above the (3,3) Resonance 706 Unpolarized p-p Differential Cross B. W. Mayes Univ. of Houston Sections at 90° m M. Furic Univ. of Zagreb, Yugoslavia 707 Study of Transfer Effects in J. J. Reidy Univ. of Mississippi Muon Capture in Gas Targets R. L. Hutson Los Alamos 708 A Measurement of the Depolarization, C. L. Hollas Univ. of Texas, Austin the Polarization and the Polarization Rotation Parameters and the Analyzing Power for the Reaction pp — pVn 709 Measurements of ANN, Ass, and ASL M. Gazzaly Univ. of Minnesota in the Coulomb Interference Region G. Pauletta UCLA at 650 and 800 MeV N. Tanaka Los Alamos 710 A Measurement of the Triple M. L. Barlett Univ. of Texas, Austin Scattering Parameters D, R, A, G. W. Hoffmann Univ. of Texas, Austin R' and A' for Quasi-Elastic Scattering at 800 MeV July-December 1981 PftOOREMATLAMPF 109 Los Alamos National Laboratory 711 Reactive Content of the Optical G. W. Hoffmann Univ. of Texas, Austin Potential at 500 MeV 712 Inelastic Proton Scattering on "Ca and R. E. Segel Northwestern Univ. MTi: An Attempt to Identify Mesonlc Effects as the Cause of M1 Quenching 713 M1's, Deltas, and Medium Effects C. Glashausser Rutgers Univ. in Cross Sections for MSr(p,pTSr* at 400 MeV 714 A Search for the Giant Isovector C. Glashausser Rutgers Univ. Monopole Resonance in Inelastic Proton Scattering at Zero Degrees 715 Analysis of Chemical Composition J. M. Oostens Oklahoma Univ. of Archeological Artifacts D. H. Snow Museum of New Mexico by Way of Muonic X Rays 716 Pion Double Charge Exchange on K. K. Seth Northwestern Univ. Heavy Nuclei 717 Pion Scattering to Collective L. C. Bland Univ. of Pennsylvania States In Selenium Isotopes C. L. Morris Los Alamos S. J. Greene New Mexico State Univ. 718 Energy Dependence of the J. Kelly MIT Two-Nucleon Effective Interaction M. V. Hynes Los Alamos 719 Production of Neutron Rich A. L. Turkevich Univ. of Chicago Radon Isotopes and Determination of Their Cross Sections and Half Lives by a Radiochemical Technique 720 Recoilless Delta Production C. L. Morris Los Alamos in the Reaction J. A. McGill Rutgers Univ. l3C(p,d)12CA 721 Measurement of the Proton B. Aas UCLA Polarization Observables in the E. Bleszynski UCLA 7Li(p,p')7Li and the Test of the Reaction Theory at Intermediate Energies 722 Measurement of Cross Sections and C. J. Harvey Univ. of Texas, Austin Analyzing Powers for Elastic S. Seestrom-Morris Los Alamos and Inelastic Scattering of 400- to 500-MeV Protons from "C 110 PftOflRESSATLAMPF July-December 1981 Los Alamos National Laboratory 723 Measurement of thtt Neutron C. J. Harvey Univ. of Texas, Austin and Proton Contributions to Excited H. T. Fortune Univ. of Pennsylvania States in 3aK by n+ smd u~ Inelastic Scattering 724 Measurement of the Lamb Shift P. O. Egan Yale Univ. in Muonlum V. W. Hughes Yale Univ. M. W. Qladisch Univ. of Heidelberg, W. Germany 725 The Effect of Rare Earth D. R. Davidson Iowa State Univ. Additions on Radiation Damage in M. S. Wechsler Iowa State Univ. Alloy HT-9 (Ferritic/Martensitic W. F. Sommer Los Alamos Alloy Steel) 726 Search for the C-Noninvariant V. L. Highland Temple Univ. Decay n° -. 3y G. H. Sanders Los Alamos 727 Measurement of the Efficiency S. E. Jones EG&G Idaho, Inc. of Muon Catalysis in Deuterium- Tritium Mixtures at High Densities 728 Study of Pion Charge Exchange G. C. Giesler Los Alamos Mechanisms by Means of Activation Techniques 729 Radiative Capture of Polarized M. A. Kovash MIT Protons by Deuterons at 500 to 800 MeV 730 Pion Production in Pion-Nucleon B. Saghai CEN, Saclay, France and Pion-Nucleus Interactions B. M. Preedom Univ. of South Carolina B. J. Dropesky Los Alamos 731 Fission Probability of the Giant A. Gavron Los Alamos Quadrupole Resonance in J. M. Moss Los Alamos Actinides July-December 1981 PROGRESS AT LAMPF 111 Los Alamos National Laboratory APPENDIX C ACTIVE AND COMPLETE EXPERIMENTS BY CHANNEL AREA B NEUTRONS AND PROTONS (AB) Exp. Phase No. Beam No. THIe Spokesman *=Complete Hours 56 STUDY OF NEUTRON SPECTRUM FROM PROTON BOM NORTHCLIFFE 1 * 0.0 BARDMENT OF DEUTERIUM IN THE 300-600-MeV REGION SIMMONS 2 * 0.0 65 NEUTRON-PROTON POLARIZATION MEASUREMENTS SIMMONS 1 * 996.8 USING A POLARIZED TARGET - PHASE I: THE n-p POLARIZATION OBSERVABLE P(8) 66 NEUTRON-PROTON POLARIZATION MEASUREMENTS SIMMONS 1 * 343.4 WITH A POLARIZED TARGET - PHASE II: THE 2 * 472.0 n-p SPIN-CORRELATION OBSERVABLE 125 ELASTIC NEUTRON-PROTON BACK-ANGLE DIFFERENTIAL DIETERLE 0.0 CROSS-SECTION MEASUREMENTS 300-800 MeV 129 PION PRODUCTION IN NEUTRON-PROTON COLLISIONS WOLFE 1 * 319.0 189 SEARCH FOR CONDENSED NUCLEAR STATES AND VAN DYCK 1 * 0.0 STUDY OF HIGH-q2 LOW-v NUCLEAR INTERACTIONS 193 MEASUREMENT OF SMALL-ANGLE NEUTRONS ELASTIC DIETERLE 1 * 1091.1 SCATTERING FROM PROTONS McFARLANE 2 * 0.0 205 (n,p) CHARGE-EXCHANGE AND NEUTRON-INDUCED KENEFICK 1 * 38.5 QUASI-FREE SCATTERING RILEY 255 MEASUREMENT OF [o(e)] FOR n-p SCATTERING AT NORTHCLIFFE 1 * 5.0 460 MeV 262 TEST OF ISOSPIN INVARIANCE IN THE REACTION BONNER 1 * 304.8 np — dn° 263 MEASUREMENT OF THE ENERGY AND ANGULAR BONNER 1 * 237.1 VARIATION OF THE np CHARGE-EXCHANGE CROSS SECTIONS 264 MEASUREMENT OF THE ENERGY VARIATIONS OF BONNER 1 * 473.1 THE nd ELASTIC DIFFERENTIAL CROSS SECTIONS NEAR 180° 279 TEST OF CHARGE SYMMETRY IN nd AND pd DIETERLE FS*a 101.0 SCATTERING McFARLANE 360 THE MEASUREMENT OF THE POLARIZATION TRANSFER ~!LEY 1 * 493.5 COEFFICIENT D, AND A, AT 800 MeV FOR THE SIMMONS REACTIONS d(p,n)2p, 'LKp.nJ'Be, AND 'Befp.nJ'B 366 NONRESONANT PION PRODUCTION IN THE REACTION MAYES 1 ' 427.7 np — irpp MUTCHLER FEASIBILITY STUDY. 112 •flOQ3ES8ATI.AMPF July-December 7987 Los Alamos National Laboratory 402 A MEASUREMENT OF THE POLARIZATION TRANSFER GLASS 166.1 COEFFICIENTS D,(0°) AND Ai(0°) IN THE SIMMONS 83.8 REACTION POLARIZED pp - nX AT 800 MeV 403 A MEASUREMENT OF THE TRIPLE-SCATTERING BONNER 0.0 PARAMETER D, FOR THE CHARGE-EXCHANGE REGION 223.8 IN np SCATTERING 457 MEASUREMENT OF THE QUASI-FREE pn AND pp BHATIA 785.0 AND FREE pp ANALYZING POWERS 500-800 MeV SIMMONS 492 POLARIMETER CALIBRATIONS AND SEARCH FOR McNAUGHTON 860.2 ENERGY-DEPENDENT STRUCTURE IN pp ELASTIC WILLARD SCATTERING VIA CROSS SECTION. ANALYZING POWER, AND WOLFENSTEIN PARAMETER MEASUREMENTS 498 MEASUREMENTS OF LONGITUDINAL CROSS-SECTION WAGNER 2 0.0 DIFFERENCE FOR LONGITUDINAL POLARIZED BEAM BURLESON 3 0.0 AND TARGETS (pp, pd, np) 504 MEASUREMENT OF THE TOTAL CROSS-SECTION PHILLIPS 1 * 1568.0 DIFFERENCE FOR PROTON-PROTON AND PROTON- NEUTRON SCATTERING IN PURE TRANSVERSE INITIAL SPIN STATES IN THE 400-800-MeV REGION 505 M-.ASUREMENT OF THE TRANSVERSE SPIN-SPIN PHILLIPS 1 * 860.2 ASYMMETRY IN THE REACTION pp - dn+ IN THE 2 0.0 500-800-MeV REGION 517 POLARIZED BEAM AND TARGET EXPERIMENTS IN THE SIMMONS 1 1294.9 p-p SYSTEM. PHASE 1. AY AND AYY FOR THE JARMER + dn CHANNEL AND AYY FOR THE ELASTIC CHANNEL NORTHCLIFFE FROM 500-800 MeV 518 POLARIZED BEAM AND TARGET EXPERIMENTS IN THE SIMMONS 1 0.0 p-p SYSTEM. PHASE 2. MEASUREMENTS OF A2r AND Axz JARMER FOR THE dn+ CHANNEL AND FOR THE ELASTIC CHANNEL NORTHCLIFFE FROM 500-800 MeV 589 FREE FORWARD np ELASTIC-SCATTERING ANALYZING POWER GLASS 1 0.0 MEASUREMENTS AT 800 MeV NORTHCLIFFE 590 MEASUREMENT OF d(e) IN p-n AND n-p SCATTERING SIMMONS 1A 0.0 AT 800 AND 650 MeV AND OTHER ENERGIES WITH NORTHCLIFFE ASSOCIATED p-p MEASUREMENTS 603 SEARCH FOR DELTAS IN A COMPLEX NUCLEUS BY TURKEVICH 1 * 38.5 A RADIOCHEMICAL TECHNIQUE 2 0.0 664 THE MEASUREMENT OF THE POLARIZATION TRANSFER GLASS 1 0.0 COEFFICIENTS A; AND D, AT 500, 650, AND 800 MeV STANEK FOR THE REACTION D(p,n)2p 665 THE MEASUREMENT OF THE INITIAL-STATE SPIN- BURLESON 1 0.0 CORRELATION PARAMETERS Cu AND C8L WAGNER IN n-p ELASTIC SCATTERING AT 500, 650, AND 800 MeV 683 MEASUREMENT OF Aot IN FR<=E NEUTRON- DITZLER 1 0.0 PROTON SCATTERING AT 500, 650, AND 800 MeV SIMMONS July-December 1981 PROGRESS AT LAMPF 113 Los Alamos National Laboratory AREA B NUCLEAR CHEMISTRY (AB-Nucchem) Exp. Phase No. Beam No. Title Spokesman *=Complete Hour* 103 SPALLATION YIELD DISTRIBUTIONS FOR PION HUDIS 0.4 INTERACTIONS WITH COMPLEX NUCLEI 104 PROPOSAL FOR LAMPF EXPERIMENT: STUDIES OF PATE 1 * 0.0 THE PROTON- AND PION-INDUCED FISSION OF 2 * 5.0 MEDIUM-MASS NUCLIDES 105 NUCLEAR SPECTROSCOPY STUDIES OF PROTON-INDUCED BUNKER 1 * 10.0 SPALLATION PRODUCTS 2 * 58.6 106 PROTON-INDUCED SPALLATION REACTIONS RELATED O'BRIEN 1 * 0.7 TO THE ISOTOPE PRODUCTION PROGRAM AT LAMPF 2 37.6 118 FRAGMENT EMISSION FROM PION INTERACTIONS PORILE 1 * 0.0 WITH COMPLEX NUCLEI 2 0.0 119 CROSS SECTIONS OF SIMPLE NUCLEAR REACTIONS KAUFMAN 2 * 15.2 INDUCED BY tr MESONS 123 NUCLEAR STRUCTURE EFFECTS IN PION-INDUCED KAROL 1 * 0.0 NUCLEAR REACTIONS 2 * 1.0 150 SEARCH FOR POLYNEUTRON SYSTEMS TURKEVICH 1 * 0.0 2 * 14.2 169 PROTON IRRADIATIONS FOR PROJECT JUMPER ORTH 1 * 0.0 SATTIZAHN 243 RECOIL STUDIES OF DEEP SPALLATION AND PORILE 55.8 FRAGMENTATION PRODUCTS FROM THE INTERACTION OF 800-MeV PROTONS WITH HEAVY ELEMENTS 282 MEASUREMENT OF CROSS SECTIONS FOR PROTON- DONNERT 0.6 INDUCED FORMATION OF SPALLATION PRODUCTS 1.5 IN COPPER BY ACTIVATION ANALYSIS 0.1 294 HIGH-ENERGY NUCLEAR REACTIONS KAROL 11.7 301 IMPAIRMENT OF SUPERCONDUCTING CHARACTERISTICS WILSON 185.0 BY PROTON IRRADIATION 349 NUCLEAR REACTIONS OF '"I WITH PIONS PORILE 3.6 407 THE EFFECT OF DISLOCATION VIBRATION ON VOID SOMMER 516.2 GROWTH IN METALS DURING IRRADIATION PHILLIPS 0.0 410 RADIATION EFFECTS IN AMORPHOUS METALS DUE TO COST 800-MeV PROTONS 583.0 424 PRELIMINARY EXPERIMENTS FOR DOUBLE CHARGE TURKEVICH EXCHANGE AND {»-,e+) SEARCHES WARREN 8.0 465 RADIOCHEMICAL STUDY OF PION SINGLE CHARGE RUNDBERG EXCHANGE 0.5 579 A RADIOCHEMICAL STUDY OF NEUTRON-DEFICIENT FAUBEL PRODUCTS FROM 500 MeV AND 2MU 0.8 114 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 610 USE OF LAMPF BEAM STOP TO OBTAIN "Fa HENNINQ 1 0.0 KUTSCHERA 629 FEASIBILITY OF HELIUM-JET TECHNIQUES FOR GREENWOOD 1 * 47.5 STUDYING SHORT-LIVED NUCLEI PRODUCED AT LAMPF BUNKER 2 0.0 TALBERT, J. 20 0 679 A RADIOCHEMICAL STUDY OF THE »BI(p,nT' Po, CLARK 0.0 "•BI(P.irxn)*l0-'At, AND iMBI(p,p2n-xn)!M-"At PION PRODUCTION REACTIONS AT 500-800 MeV 719 PRODUCTION OF NEUTRON-RICH RADON ISOTOPES AND TURKEVICH 0.0 DETERMINATION OF THEIR CROSS SECTIONS AND HALF LIVES BY A RADIOCHEMICAL TECHNIQUE BIOMEDICAL PION CHANNEL (BIOMED) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 44 RADIOBIOLOGY OF ir MESONS, A PRELIMINARY CARLSON 1 * 75.0 STUDY 84 QUALITY OF MESON RADIATION FIELDS PHILLIPS. 1 * 0.0 143 STUDY OF THE RADIOBIOLOGICAL PROPERTIES KLIGERMAN 1 * 0.0 OF NEGATIVE PIONS KNAPP 2 * 0.0 3 * 0.0 151 AN INVESTIGATION OF PION DOSIMETRY BY PASSIVE KNOWLES 1 " 8.C PARTICLE DETECTORS 167 HEAVY FRAGMENT FORMATION FOLLOWING THE ZIOCK 0.0 ABSORPTION OF n" IN "C 171 STUDY OF NEGATIVE PION BEAMS BY MEANS OF BENTON 0.0 PLASTIC NUCLEAR TRACK DETECTORS 187 NUCLEAR GAMMA RAYS PRODUCED BY NEGATIVE REIDY 21.6 PIONS STOPPING IN CARBON, NITROGEN, OXYGEN, AND TISSUE 195 NUCLEAR RESONANCE EFFECT IN PIONIC ATOMS LEON 0.0 REIDY 155.2 196 A VISUALIZATION EXPERIMENT WITH CHARGED DANIEL 0.0 PARTICLES REIDY 198 EFFECTS OF PIONS ON DNA OF NONDIVIDING CELL POWERS 0.0 SYSTEMS 207 MEASUREMENT OF NEUTRON SPECTRUM AND INTENSITY BRADBURY 1 * 0.0 RESULTING FROM n" CAPTURE IN WATER PHANTOM ALLRED AND HUMAN TISSUE 209 PION INTERACTIONS IN NUCLEAR EMULSIONS BRADBURY 1 * 0.0 ALLRED 212 COMPARATIVE EFFECTIVENESS OF NEGATIVE PIONS MEWISSEN 0.0 vs "!Cf IN A TUMOR ANIMAL SYSTEM July-December 1981 PROGRESS AT LAMPF 115 Los Alamos National Laboratory 215 VISUALIZATION OF STOPPING PION DISTRIBUTION PEREZ-MENDEZ 172.1 BRADBURY 217 n- PRODUCTION CROSS SECTIONS PACIOTTI 218 PION DOSIMETRY WITH NUCLEAR EMULSIONS AND KATZ ALANINE 235 RADIATION REPAIR OF NORMAL MAMMALIAN TISSUES GILLETTE 236 BIOLOGICAL EFFECTS OF NEGATIVE PIONS RAJU 239 STUDY OF "C AND ,3N PRODUCTION BY tr FRIEDLAND IRRADIATION OF CARBON, NITROGEN, OXYGEN, AND MAUSNER TISSUE FOR RADIOTHERAPY MONITORING 242 SURVIVAL OF SYNCHRONIZED CULTURED HUMAN TODD KIDNEY T-1 CELLS EXPOSED TO STOPPING PIONS AND X RAYS AT VARIOUS TIMES AFTER MITOSIS 244 SYSTEMS DEVELOPMENT FOR EFFICIENT UTILIZATION BRILL OF HIGH-PURITY GERMANIUM MOSAIC DETECTORS FOR TUMOR UTILIZATION 270 THERAPY BEAM DEVELOPMENT — BIOMEDICAL PACIOTTI CHANNEL TUNING 271 THERAPY BEAM DEVELOPMENT — DOSIMETRY SMITH 272 THERAPY BEAM DEVELOPMENT — MICRODOSIMETRY DICELLO 273 THERAPY BEAM DEVELOPMENT - LET MEASUREMENTS RICHMAN 274 PION RADIOBIOLOGY BUSH 275 PION CLINICAL TRIALS BUSH 285 MIGRATION OF "C AND "N RADIOACTIVITY MAUSNER PRODUCED IN VIVO BY ir 300 NEGATIVE PIONS COULOMB CAPTURE AND NEGATIVE DANIEL PIONS TRANSFER IN TISSUE, TISSUE-EQUIVALENT LEON LIQUID, AND SIMPLE COMPONENTS LEON 304 STUDY OF THE AUGER PROCESS IN PIONIC ATOMS MAUSNER PHILLIPS 380 RBE AND OER FOR NORMAL AND TUMOR TISSUE GOLDSTEIN 384 PF USING MOUSE TESTES AS A BIOLOGICAL TEST GERACI SYSTEM BEAM STOP A RADIATION (BSA-RAD) Exp. PhaM No. BMm No. Till* Spokitman *=Complete Hour* 45 RADIATION-DAMAGE STUDIES - HIGH-TEMPERATURE DUDZIAK 1 * 0.0 REACTOR MATERIALS AND TYPE II SUPERCONDUCTORS GREEN 2 * 1833.0 GIORGI 116 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 111 SEARCH FOR NEW NEUTRON-RICH NUCLIDES PRODUCED HILL 0.0 BY FAST NEUTRONS 10.8 113 RADIATION DAMAGE AND HELIUM EMBRITTLEMENT IN MICHEL 0.0 ELEVATED TEMPERATURE REACTOR STRUCTURAL ALLOYS 161 THE MICRODISTRIBUTION OF THORIUM IN METEORITES BURNETT 11.7 174 INVESTIGATION OF THE CHEMICAL REACTIONS ROWLAND 0.0 OF ATOMIC "F AS A MEANS FOR DIRECT SYNTHESIS MILLER 7.0 OF "F-LABELED COMPOUNDS 326 ELECTRICAL COMPONENT RADIATION EFFECTS STUDY HARVEY 294.5 179.9 406 NEUTRON FLUX CHARACTERIZATION AT A-6 HARVEY 1306.3 RADIATION EFFECTS FACILITY 415 TWO-NUCLEON-OUT PRODUCTS FROM STOPPED n" ORTH 0.0 INTERACTIONS 467 IRRADIATION IN SUPPORT OF FERFICON STUDIES GILMORE 0.4 542 FEASIBILITY STUDY — USING AN EXISTING NEUTRON LU 699.7 BEAM PIPE AT LAMPF BEAM STOP FOR CRYSTAL 0.0 DIFFRACTION SPECTROMETER EXPERIMENTS 545 FUSION MATERIALS NEUTRON IRRADIATIONS - BROWN 0.0 A PARASITE EXPERIMENT 554 IRRADIATION OF TECHNOLOGICALLY IMPORTANT BROWN 75.2 METALS WITH 800-MeV PROTONS USING THE COST 0.0 ISOTOPE PRODUCTION FACILITY AT LAMPF 0.0 560 STUDY OF NEUTRON-IRRADIATION-INDUCED GROWTH HARVEY 63.4 OF METALS AT RADIATION EFFECTS FACILITY 691 SIMULATION OF COSMIC-RAY PRODUCTION OF NUCLIDES REEDY 0.0 BY SPALLATION-PRODUCED NEUTRONS EXTERNAL PROTON BEAM (EPB) Exp. PIUMNO. Beam No. Till* Spokesman *=Compl«t« Hours 26 NEUTRON TIME-OF-FLIGHT EXPERIMENT AT BEAM STOP VEESER 0.0 27 p-p SPIN-CORRELATION EXPERIMENTS WILLARD 4 » 0.0 2 * 1141.8 42 BREAKUP OF FEW-NUCLEON SYSTEMS AND NUCLEI COLE 4 • 530.8 81 STUDY OF NEUTRON-PROTON AND PROTON-PROTON PHILLIPS 1 • 0.0 COINCIDENCE SPECTRA FROM p+d-n+p+p REACTION 9 * 600.5 128 WNR STORAGE RING STRIPPER EXPERIMENT HAYWARD 1 • 0.0 137 SEARCH FOR PARITY VIOLATING CONTRIBUTION NAGLE 1 • 316.6 TO SCATTERING OF HADRONS MISCHKE 2 * 363.4 FRAUENFELDER 3 * 346.5 July-December 1981 PROGRESS AT LAMPF 117 Los Alamos National Laboratory 153 INVESTIGATION OF NUCLEAR GAMMA RAYS RESULTING EISENSTEIN 1 * 0.0 FROM IN-FLIGHT PION AND PROTON REACTIONS 159 CHARGED-PARTICLE EMISSION IN PROTON-INDUCED EISENSTEIN 0.0 REACTIONS AS A FEASIBILITY STUDY IN THE USE OF INTRINSIC GERMANIUM DETECTORS WITH THE PRIMARY LAMPF BEAM 176 p-NUCLEUS TOTAL AND TOTAL REACTION CROSS- ANDERSON 1 * 0.0 SECTION MEASUREMENTS 2 * 296.6 192 MEASUREMENT OF THE EMITTANCE GROWTH IN HAYWARD 1 * 70.0 H" STRIPPING 194 p-p, D, R, AND A MEASUREMENTS McNAUGHTON 1 * 185.2 2 * 498.5 197 INVESTIGATION REACTION p + d - 3He + n° HUNGERFORD 1 * 363.0 AT LAMPF ENERGIES 200 STUDY OF THE PHOTODETACHMENT SPECTRUM OF BRYANT 1 * 128.8 H" IN THE VICINITY OF 11 eV 219 DOUBLE PION PRODUCTION IN PROTON-PROTON BEVINGTON 1 * 422.0 SCATTERING HOFFMANN FS* 66.3 223 STUDIES OF THE (p,np) CHARGE-EXCHANGE REACTION HOFFMAN 1 * 531.2 241 DIRECT LEPTON PRODUCTION AT LAMPF ENERGIES MISCHKE 278 STUDY OF REACTION MECHANISMS USING INTERNAL HOFFMANN 1 * 53.0 CONVERSION TECHNIQUES MOORE 279 TEST OF CHARGE SYMMETRY IN nd AND pd DIETERLE FS* 67.0 SCATTERING McFARLANE 1 * 0.0 289 MEASUREMENT OF THE PHASE OF THE FORWARD WHITTEN 1 * 354.6 NUCLEON-NUCLEON SPIN-INDEPENDENT ELASTIC- SCATTERING AMPLITUDE AT 800 MeV 323 STARK EFFECT QUENCHING OF RESONANCES IN BRYANT 1 * 350.6 THE PHOTODISINTEGRATION OF THE H- ION GRAM 336 STUDY OF THE SPIN DEPENDENCE OF PROTON- MUTCHLER 1 * 419.4 PROTON PION PRODUCTION REACTIONS PINSKY 2 0.0 3 0.0 4 0.0 339 SURVEY OF PHOTODETACHMENT CROSS SECTION BRYANT 1363.1 OF H- FROM THRESHOLD TO 15 eV AND ITS DEPENDENCE GRAM UPON ELECTRIC FIELD 341 STUDY OF pd - dn+n REACTION MECHANISMS PHILLIPS 229.0 449 SURVEY OF SINGLE AND DOUBLE PHOTODETACHMENT BRYANT 570.7 CROSS SECTION OF THE H" ION FROM 14 TO 21.8 eV DONAHUE 229.9 468 MECHANISMS OF LUMINESCENCE INDUCED BY PROTONS BECHER 70.8 INCIDENT OF ULTRAVIOLET GRADE OPTICAL MATERIALS 492 POLARIMETER CALIBRATIONS AND SEARCH FOR MoNAUGHTON 0.0 ENERGY-DEPENDENT STRUCTURE IN pp ELASTIC WILLARD SCATTERING VIA CROSS SECTION, ANALYZING POWER, AND WOLFENSTEIN PARAMETER MEASUREMENTS 118 PROGRESS AT LAMPF July-December J 987 Los Alamos National Laboratory 498 MEASUREMENTS OF LONGITUDINAL CROSS-SECTION WAGNER 1664.5 DIFFERENCE FOR LONGITUDINAL POLARIZED BEAM BURLESON AND TARGETS (pp, pd, np) 512 PROTON-PROTON ELASTIC-SCATTERING MEASUREMENTS GREENE 835.0 OF THE Ass(9), ALl(8), AND Asl(9) SPIN-CORRELATION IMAI 0.0 PARAMETERS AT 500, 650, and 800 MeV 0.0 0.0 530 H- MAGNETIC STRIPPING RATES JASON 237.2 586 A STUDY OF THE EFFECTS OF VERY STRONG ELECTRIC BRYANT 0.0 FIELDS ON THE STRUCTURE OF THE H" ION GRAM 587 FUNDAMENTAL EXPERIMENTS WITH RELATIVISTIC SMITH 0.0 HYDROGEN ATOMS - EXPLORATORY WORK DONAHUE 588 A SEARCH FOR LONG-LIVED STATES OF THE H~ ION CLARK 0.0 BRYANT 591 AN INVESTIGATION OF INCLUSIVE ONE-PION DEVRIES 651.1 PRODUCTION IN PROTON-NUCLEUS COLLISIONS DIGIACOMO 592 AN INVESTIGATION OF TWO-PION PRODUCTION DEVRIES 0.0 AND CORRELATIONS IN PROTON-NUCLEUS COLLISIONS DIGIACOMO AT 800 MeV 633 MEASUREMENT OF p-p ELASTIC SCATTERING IN PAULETTA 0.0 THE COULOMB INTERFERENCE REGION BETWEEN IROM 300 AND 800 MeV 634 MEASUREMENT OF PARITY VIOLATION IN THE CARLINI 299.2 p-NUCLEUS TOTAL CROSS SECTIONS AT 800 MeV TALAGA YUAN 635 SPIN MEASUREMENTS IN pd ELASTIC SCATTERING BONNER 507.7 IGO 0.0 BLESZYNSKI 636 A MEASUREMENT OF THE WOLFENSTEIN POLARIZATION HOLLAS 0.0 PARAMETERS DLL, D5l, KLt, AND KSL FOR p-p ELASTIC SCATTERING 637 A MEASUREMENT OF THE VECTOR POLARIZATION BONNER 0.0 OF THE DEUTERON IN THE REACTION pp - dn+ 690 SIMULATIONS OF COSMIC-RAY-PRODUCED GAMMA RAYS REEDY 0.0 FROM THICK TARGETS 706 UNPOLARIZED p-p DIFFERENTIAL CROSS SECTIONS MAYES 0.0 AT 90° cm. FURIC 708 A MEASUREMENT OF THE DEPOLARIZATION, THE HOLLAS 0.0 POLARIZATION, AND THE POLARIZATION ROTATION 0.0 PARAMETERS AND THE ANALYZING POWER FOR THE 0.0 REACTION pp ->• pn+n July-December 1981 PROGRESS AT LAMPF 119 Los Alamos National Laboratory ENERGETIC PION CHANNEL SPECTROMETER (EPICS) Exp. Phase No. Baam No. Till* Spokesman *=Compl*t* Hour* 9 ELASTIC AND INELASTIC PION SCATTERING FROM MCCARTHY CALCIUM ISOTOPES MORRIS 13 STUDY OF nMNDUCED DOUBLE-CHARGE-EXCHANGE SETH REACTIONS 14 n* AND n" ELASTIC AND INELASTIC SCATTERING THIESSEN FROM "O 18 SURVEY OF TT SCATTERING BY COMPLEX NUCLEI ZEIDMAN 23 A SURVEY OF PION-NUCLEUS ELASTIC AND WHARTON INELASTIC SCATTERING AT 180 MeV 39 SEARCH FOR (n,p) REACTIONS WITH EPICS MACEK THIESSEN 74 STUDY OF PION-INDUCED DOUBLE-CHARGE-EXCHANGE PEREZ-MENDEZ REACTIONS ON LOW-Z ELEMENTS STETZ 87 rt+ AND rr" SCATTERING FROM 3He AND *He MCCARTHY 130 EPICS TUNEUP PROPOSAL: PION CARBON THIESSEN SCATTERING 133 PRELIMINARY PION CHANNELING EXPERIMENTS GEMMELL 156 SURVEY OF QUASI-ELASTIC PION SCATTERING SWENSON 229 n+ vs n" INELASTIC EXCITATION OF LOW-LYING BRAITHWAITE COLLECTIVE STATES IN !,N NUCLEI MOORE 245 STUDY OF THE (tr,n) AND (ir.rrp) REACTIONS IN KALLNE 3'He AND HEAVIER NUCLEI BY DETECTING THIESSEN RECOILING TRITONS OR DEUTERONS 246 STUDIES OF n+ SCATTERING AT 50 MeV EISENSTEIN FROM LIGHT NUCLEI 265 STUDY OF PROMPT NUCLEAR DEEXCITATION GAMMA MORRIS RAYS FROM PION INTERACTIONS WITH "LI AND "C BRAITHWAITE 310 (n\tr) DOUBLE-CHARGE-EXCHANGE REACTIONS BRAITHWAITE USING CORE 2n TARGETS MORRIS 317 INELASTIC PION SCATTERING TO THE 1+ STATES PETERSON OF "C 325 PION AND MUON MULTIPLE COULOMB-SCATTERING HANSON EXPERIMENT ON THE EPICS BEAM LINE 342 STUDY OF THE (n+,p) REACTION IN ,2C MCCARTHY KALLNE 368 ELASTIC PION SCATTERING TO THE 19.2 ± 0.3 MeV MOORE STATE IN "C 120 PROGRESS AT LAMPF July-December 7987 Los Alamos National Laboratory 369 INELASTIC PION SCATTERING BY "0, "0, AND 1,F DEHNHARD 1 * 318.1 389 INELASTIC PION SCATTERING FROM LIGHT NUCLEI MORRISON 1 * 685.0 ioBi nB| nNi AND i5N ZEIDMAN 2 * 0.0 3 * 132.0 391 INELASTIC n* SCATTERING ON 'LI PETERSON 1 * 201.7 413 MASS MEASUREMENT OF "Ne AND "Ar BY THE SETH 1 * 0.0 (n-,n+) REACTION NANN 419 n+ vs TI- INELASTIC EXCITATION OF SINGLE- BRAITHWAITE 1 * 25.3 !0, PARTICLE AND CORE-COUPLED STATES IN Pb AND MORRIS ao»BI MOORE 442 STUDY OF THE INCLUSIVE PION DOUBLE-CHARGE- KALLNE 1 • 124.7 EXCHANGE REACTION 446 STUDY OF EO GIANT RESONANCES HALPERN 0.0 EISENSTEIN THIESSEN 448 STUDY OF n+ DOUBLE-CHARGE-EXCHANGE BURLESON 399.7 SCATTERING AT SMALL ANGLES ON VARIOUS NUCLEI 452 ELASTIC AND INELASTIC SCATTERING OF n* DEHNHARD 219.5 BY "C 456 THE (n,d) REACTION ON 12C AT 60 MeV HOISTAD 0.0 460 AN INVESTIGATION OF THE STABILITY OF "H, SETH 444.7 7H, AND »He BY (TT.TT*) REACTIONS 463 COMPARATIVE STUDY OF THE (n\rr) AND NANN 444.7 (TT-,IT+) REACTIONS ON "C SETH 478 it* ELASTIC SCATTERING FROM DEUTERIUM MASTERSON 1 * 148.3 481 EXCITATION OF HIGH-SPIN STATES IN T2 = 0 GEESAMAN 1 * 134.7 s-d SHELL NUCLEI BY PION ELASTIC SCATTERING 484 INELASTIC PION SCATTERING FROM 14,Sm AND ,52Sm MORRIS 1 * 70.7 495 ISOSPIN MIXING IN "C MORRIS 1 * 424.1 BRAITHWAITE 506 INELASTIC PION SCATTERING TO THE UNNATURAL COTTINGAME 1 * 0.0 PARITY LEVELS IN 12C AND 'LI BRAITHWAITE 510 ENERGY DEPENDENCE OF ELASTIC AND INELASTIC DEHNHARD 61.1 SCATTERING OF n± BY "C BETWEEN 116 AND 280 MeV 0.0 516 THE (n+,p) REACTION OF "•'•O ANDERSON 36.0 HOISTAD 522 EXCITATION OF GIANT RESONANCE STATES IN KING 198.6 aoZr AND !MPb WITH 150-MeV PIONS ANDERSON PETERSON 539 SEARCH FOR PURE NEUTRON/PROTON TRANSITIONS BAER 345.7 IN "C HOLTKAMP 546 INVESTIGATION OF THE SPIN FORM FACTOR OF BRISCOE FS* 60.9 TRITIUM AND 3He NEFKENS 1 * 240.0 July-December 1981 PROGRESS AT LAMPF 121 Los Alamos National Laboratory 549 A STUDY OF THE DCX REACTION MECHANISM — SETH THE "Ca(n+,n-)«Ti REACTION 550 EXCITED-STATE SPECTRA OF THE EXOTIC NUCLEI SETH "C AND "Ne BY (n",n+) DCX REACTIONS 551 MASSES OF «TI AND "Zn SY (ir,n+) REACTIONS SETH 558 MEASUREMENT OF (ti+,tr) REACTIONS ON BAER 13 "C AND aMg BURLESON 565 EXCITATION OF HIGH-SPIN PARTICLE-HOLE STATES ZEIDMAN IN "Fe AND MNI GEESAMAN 570 INVESTIGATION OF THE STRUCTURE OF "0 WITH HOLTKAMP PION INELASTIC SCATTERING FORTUNE 572 A-DEPENDENCE OF THE (n+.iT) REACTION AND GREENE THE WIDTH OF A DOUBLE ISOBARIC ANALOG MOORE STATE IN HEAVY NUCLEI 573 PION SCATTERING FROM "Mg AND "Mg BLANPIED 577 MEASUREMENT OF ANGULAR DISTRIBUTIONS FOR GREENE "OK.n-VNe FORTUNE 581 n* ELASTIC SCATTERING FROM DEUTERIUM MASTERSON AT 237 MeV BOUDRIE 597 THE STUDY OF BROAD-RANGE PION INELASTIC HALPERN SCATTERING SPECTRA (WITH EMPHASIS ON THE EISENSTEIN EXCITATION OF THE GIANT MONOPOLE RESONANCE) 598 INELASTIC PION SCATTERING TO THE UNNATURAL COTTINGAME PARITY LEVELS IN «LI KIZIAH 601 DETERMINATION OF ISOSCALAR AND ISOVECTOR HINTZ TRANSITION RATES FOR LOW-LYING COLLECTIVE STATES IN MZr AND 201Pb BY ti+ AND n- INELASTIC SCATTERING 602 NEUTRON-PROTON COMPONENTS OF INELASTIC HARVEY TRANSITIONS IN PION SCATTERING ON 23Na AND DEHNHARD 25Mg 604 AN INVESTIGATION OF THE NEAR STABILITY OF 5H SETH 605 A DIBARYON SEARCH AT EPICS SETH 606 TESTS OF THE (N - Z) DEPENDENCE OF PION SETH DOUBLE CHARGE EXCHANGE 612 MASS OF "Be SETH 617 A STUDY OF THE (3/2,3/2) RESONANCE IN ZIOCK LIGHT NUCLEI 619 INELASTIC PION SCATTERING TO 0* AND 2* MOORE STATES IN "Ca AND "Ca FORTUNE MORRIS 622 INVESTIGATION OF THE STRONG CANCELLATIONS HOLTKAMP OF NEUTRON-PROTON TRANSITION AMPLITUDES IN "C BAER 122 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 625 INELASTIC SCATTERING OF PIONS TO GIANT KING 162.0 RESONANCES ANDERSON PETERSON 651 MEASUREMENT OF A LOWER LIMIT FOR THE MORRIS 0.0 SUBTHRESHOLD PRODUCTION OF KAONS WITH 800-MeV PROTONS 655 TT± INELASTIC SCATTERING FROM 4He — HOLTKAMP 0.0 AN EXAMINATION OF ISOSPIN SYMMETRY BREAKING COTTINGAME 657 INELASTIC n* SCATTERING FROM THE N = 26 SEIDL 0.0 ISOTONES MOORE 659 SPIN-FLIP GIANT RESONANCE EXCITATION BLAND 0.0 MOORE 661 GOOD-RESOLUTION STUDY OF "Ofn.n1) MORRIS 0.0 BLAND + 662 ELASTIC AND INELASTIC IT AND n SCATTERING KRAUSHAAR 0.0 FROM 32S, 3'P AND ">Zr, "Y PETERSON 671 EXPERIMENTAL INVESTIGATIONS OF ISOVECTOR SAHA 0.0 PROPERTIES OF COLLECTIVE TRANSITIONS SETH 672 STUDY OF GIANT RESONANCES IN MZr, "'Sri, CAREY 0.0 AND 2MPb WITH n+ AND IT INELASTIC SCATTERING MOSS 677 A DETERMINATION OF AS = 1 CONTRIBUTIONS IN HOLTKAMP 0.0 INELASTIC PION SCATTERING FROM ODD-A NUCLEI FUNSTEN 678 STUDY OF THE M1 TRANSITION IN "Ca BY INELASTIC DEHNHARD 0.0 SCATTERING OF n+ AND ir MORRIS 681 MEASUREMENTS OF LARGE-ANGLE PION-NUCLEUS BURLESON 0.0 SCATTERING WITH EPICS SETH 0.0 694 ISOSPIN MIXING IN 4He FORTUNE 0.0 700 DOUBLE CHARGE EXCHANGE ON «°Ar MORRIS 701 PION DOUBLE CHARGE EXCHANGE ON SELF- MORRIS 0.0 CONJUGATE NUCLEI FORTUNE 702 NUCLEAR STRUCTURE EFFECTS IN PION SCATTERING COMFORT 0.0 FROM 92,w!Mo 703 STUDY OF M4 STRENGTH IN ,!N BY n+ AND ir HOLTKAMP 0.0 INELASTIC SCATTERING SEESTROM-MORRIS 704 PION INELASTIC SCATTERING FROM »Ne MOORE 0.0 FORTUNE 716 PION DOUBLE CHARGE EXCHANGE ON HEAVY NUCLEI SETH 0.0 717 PION SCATTERING TO COLLECTIVE STATES IN BLAND 0.0 SELENIUM ISOTOPES MORRIS GREENE 723 MEASUREMENT OF THE NEUTRON AND PROTON HARVEY 0.0 CONTRIBUTIONS TO EXCITED STATES IN MK BY FORTUNE n+AND ir INELASTIC SCATTERING July-December 1981 PROGRESS AT LAMPF 123 Los Alamos National Laboratory HIGH-RESOLUTION SPECTROMETER (HRS) Exp. Phata No. Baam No. Title Spokeeman '-Complete Hour* 4 LARGE-ANGLE ELASTIC SCATTERING OF PROTONS IGO 458.0 FROM HELIUM AND QUASI-ELASTIC KNOCKOUT OF ALPHA PARTICLES BY 800-MeV PROTONS 5 INELASTIC SCATTERING OF 800-MeV PROTONS CHRIEN 532.7 FROM NUCLEI TO STUDY QUASI-FREE MODES PALEVSKY 10 SEARCH FOR (p,n) REACTIONS WITH HRS SPENCER 1 * 167.9 15 ELASTIC SCATTERING AND TOTAL CROSS-SECTION IGO 1 • 0.0 MEASUREMENTS OF PROTON ON HYDROGEN, TANAKA DEUTERIUM, AND HELIUM 2 * 75.0 3 * 249.0 49 ELASTIC AND INELASTIC PROTON SCATTERING PETERSON 68.3 FROM THE NICKEL ISOTOPES AND FROM "Y 117 HIGH-RESOLUTION STUDY OF THE NEUTRON IGO 273.2 PICK-UP REACTION 138 INELASTIC PROTON SCATTERING AND EXCITATION McDANIELS 184.2 OF STATES OF INTERMEDIATE COLLECTIVITY IN SWENSON OPEN-SHELL NUCLEI 139 PRELIMINARY PROTON SCATTERING SURVEY WITH SPENCER 695.1 HRS TANAKA 178 PROTON SCATTERING SURVEY ON s-d SHELL SPENCER 209.3 NUCLEI HINTZ 183 PROTON SCATTERING SURVEY ON HEAVY DEFORMED HINTZ 382.1 NUCLEI SPENCER 204 EXCITATION AND ASYMMETRY MEASUREMENT OF IGO 127.0 T =. 1, HIGH-SPIN, NONNORMAL PARITY PARTICLE-HOLE STATE BY (p,p') SCATTERING IN THE INTERMEDIATE-ENERGY RANGE 223 STUDIES OF THE (p,np) CHARGE-EXCHANGE REACTION HOFFMANN FS* 0.0 233 SEARCH FOR DELTA-CONFIGURATIONS NUCLEI SETH 1 * 167.9 SPENCER 249 THE (P,TT+) REACTION ON 4He WITH 800-MeV PROTONS WHITTEN 1 * 296.7 256 p-NUCLEUS ELASTIC SCATTERING AT q! = 8 GeV2 IN FRANKEL 1 * 107.6 Be, C, AND THE STUDY OF p-NUCLEUS INTER ACTIONS IN Co AND Au UP TO m' = q!/2v a 20 258 STUDY OF MECHANISMS FOR THE EJECTION OF FRANKEL 178.7 HIGH-MOMENTUM PARTICLES FROM NUCLEI BY FRATI 0.0 STUDY OF THE COINCIDENCE SPECTRUM IN p + a - (p,d,t) + (p,d,t) + X 261 INTERMEDIATE-ENERGY (p,d) REACTION MECHANISM RICKEY 0.0 STUDIES SHEPARD PETERSON 124 PROQBEMATLAMPF July-December 1981 Los Alamos National Laboratory 311 ELASTIC-SCATTERING SURVEY USING POLARIZED HOFFMANN 715.3 PROTONS 245.6 346 STUDY OF HIGH-MOMENTUM COMPONENTS IN NUCLEI FRANKEL 209.8 USING A POLARIZED PROTON BEAM 347 SEARCH FOR ORBIT-FLIP STATES BY INELASTIC HINTZ 209.3 PROTON SCATTERING 352 DETERMINATION OF NEUTRON-MASS DISTRIBUTION WHITTEN 204.6 FROM ELASTIC PROTON MEASUREMENTS [P(t) AND do/dt] ON ISOTOPES IN THE CALCIUM REGION ,! 354 SCATTERING OF 800-MeV PROTONS FROM C BLANPIED 324.1 AND "C AT MOMENTUM TRANSFER >4 F"1 355 FURTHER ELASTIC SCATTERING CROSS SECTION HOFFMANN 130.0 M, AND ANALYZING POWER MEASUREMENTS ON Pb 55.0 AND "••'»Sn 356 ANALYZING POWER AND CROSS-SECTION MEASURE GLASHAUSSER 199.9 MENTS FOR INELASTIC PROTON EXCITATION OF SIMPLE BAKER 88.1 STATES SCOTT 385 MEASUREMENT OF THE POLARIZED PROTONS + HOFFMANN 140.6 NEUTRONS ANALYZING POWER AY(e) FROM 6cm 10-70° 108.8 386 TOTAL REACTION CROSS SECTIONS FOR p* NUCLEI HOFFMANN 256.1 AT 800 MeV BURLESON 118.2 YOKOSAWA 30.0 392 A MEASUREMENT OF THE TRIPLE-SCATTERING HOFFMANN 208.6 PARAMETERS D, R, A, R', AND A' FOR PROTON-PROTON 187.0 AND PROTON-NEUTRON SCATTERING AT 800 MeV 0.0 395 THE (p,n+) REACTION ON "O AND 40Ca BAUER 195.8 HOISTAD NANN 399 EXCITATION OF GIANT MULTIPOLE RESONANCES BERTRAND 40.0 BY 200-400-MeV PROTONS 0.0 405 THE (p,n-) REACTION ON ,2C AND ,3C HOISTAD 162.7 BAUER SETH 411 MEASUREMENT OF SPIN-FLIP PROBABILITIES HINTZ 247.0 IN PROTON INELASTIC SCATTERING AT 800 MeV MOSS AND SEARCH FOR COLLECTIVE SPIN-FLIP MODES, PRELIMINARY SURVEY 425 PROTON ELASTIC SCATTERING AT -600 MeV BY SETH 1 * <>83.2 ""•Ca, ,0Zr, AND 20,Pb HOFFMANN 431 CROSS SECTION AND ANALYZING POWER FOR GLASHAUSSER 1 * 181.0 INELASTIC PROTON EXCITATION OF UNNATURAL PARITY MOSS STATES IN 'Li, "C, "N, AND "O 432 CROSS SECTION FOR EXCITATION OF UNNATURAL GLASHAUSSER 148.9 PARITY STATES IN "C AT E_ < 800 MeV MOSS July-December 1981 PROGRESS AT LAMRF 125 Los Alamos National Laboratory 433 ELASTIC SCATTERING DIFFERENTIAL CROSS SECTIONS HOFFMANN 0.0 AND ANALYZING POWERS FOR POLARIZED p + "«Ca, SETH "Zr, AND *"Pb AT ~400 MeV 438 THE (p,d) REACTIONS ON ""C, 'LI. "O, IGO 162.5 "Mg, "SI, AND "Cu BETWEEN 650 AND 800 MeV 451 INELASTIC PROTON SCATTERING IN THE RANGE HINTZ 221.3 300 TO 500 MeV 0.0 462 ANALYZING POWER AND DIFFERENTIAL CROSS SETH 118.0 SECTIONS FOR THE REACTIONS p + p - d + it* AND NANN p + d - t + n+ AT ~600 AND 400 MeV 470 REACTIVE CONTENT OF THE OPTICAL POTENTIAL BARLETT 247.5 HOFFMANN 472 STUDY OF THE (p,d) REACTION ON »°Zr, WHITTEN 79.5 "°Ce, AND 2MPb AT 800 MeV 473 STUDY OF GIANT MULTIPOLE RESONANCES WITH 800-MeV MOSS 110.8 PROTONS ADAMS 197.7 CAREY 474 A MEASUREMENT OF SPIN-DEPENDENT EFFECTS CORNELIUS 0.0 IN p + d ELASTIC AND INELASTIC SCATTERING 2 475 SCATTERING OF 0.8-GeV PROTONS FROM °Ne BLANPIED 154.9 AND !2Ne 0.0 476 THE ANALYZING POWER FOR POLARIZED PROTONS BLANPIED 147.6 + 242"Mg AT 500 AND 800 MeV 479 MEASUREMENT OF R, A, R\ AND A' IN ELASTIC AND IGO 178.3 INELASTIC SCATTERING OF 800-MeV PROTONS FROM LIGHT 0.0 NUCLEI — REVISED VERSION OF Q PROPOSAL 485 THE ENERGY DEPENDENCE IN THE (p,n±) REACTION HOISTAD 0.0 SHEPARD 486 INELASTIC SCATTERING OF PROTONS POPULATING IGO 65.6 THE 4- (3.44-MeV) LEVEL OF 20,Pb — A SEARCH GLASHAUSSER FOR CRITICAL OPALESCENCE MOSS 489 SEARCH FOR M1 GIANT RESONANCES IN THE (p,p') MOSS 63.9 REACTION AT E„ = 800 MeV 506 DIBARYON RESONANCES IN PION PRODUCTION SETH 178.0 171.0 519 STUDY OF THE REACTION p(pol) + d - (p.n) + X FRANKEL 130.3 TO MEASURE TKE ANALYZING POWER AND STRUCTURE FUNCTION FOR BACKWARD PARTICLES 520 STUDY OF THE REACTION VAN DYCK 127.0 p(POLARIZED) + "He - (p.d.n..) + X TO MEASURE THE ANALYZING POWER STRUCTURE FUNCTIONS FOR BACKWARDS PARTICLES 531 EXCITATION OF UNNATURAL PARITY STATES IN GLASHAUSSER 101.3 ,2C AT 500 MeV MOSS 533 THE ASYMMETRY IN THE (p,n) REACTION ON HOISTAD 0.0 "LI AT 800 MeV SETH 126 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 535 A STUDY OF THE RELATION BETWEEN THE (p,d) AND ANDERSON 0.0 (n,p) REACTION IN A PION EXCHANGE MODEL HOISTAD 538 ANALYZING POWER AND CROSS-SECTION MEASURE- SHEPARD 43.0 4 3 MENTS OF THE He(p,d) He REACTION KING 0.0 540 ELASTIC SCATTERING FROM LIGHT NUCLEI IGO 0.0 BLESZYNSKI 556 A PROPOSAL TO STUDY THE (p.p1) PROCESS BERTOZZI 52.6 LEADING TO n-ATOMIC STATES 563 p + p ELASTIC SCATTERING AT 800 AND 500 MeV HOFFMANN 1 76.3 580 CROSS SECTIONS AND ANALYZING POWERS FOR SEESTROM-MORRIS 1 43.6 ELASTIC AND INELASTIC SCATTERING OF 515-MeV DEHNHARD PROTONS FROM "C 583 MEASUREMENT OF Ctt IN THE COULOMB PAULETTA 1 0.0 INTERFERENCE REGION GAZZALY 585 MEASUREMENT OF p-p AND p-d ELASTIC SCATTERING PAULETTA 1 * 106.0 IN THE COULOMB INTERFERENCE REGION BETWEEN 500 AND 800 MeV 616 MEASUREMENT OF THE WOLFENSTEIN PARAMETERS BLESZYNSKI 237.4 + FOR THE 1 STATES OF "C MCCLELLAND 0.0 HINTZ MOSS 623 MEASUREMENT OF CROSS SECTION, ANALYZING GLASHAUSSER 0.0 POWER, AND DEPOLARIZATION PARAMETERS IN THE 2,SI(p,p')2,,Si (6- T = 0 AND T = 1) REACTION AT 400 MeV 626 MEASUREMENT OF THE DEPOLARIZATION PARAMETERS GLASHAUSSER 0.0 DNN'. DLS'. AND DSS. IN MOGILL PROTON-NUCLEUS SCATTERING AT VERY HIGH EXCITATION ENERGIES 627 MEASUREMENT OF THE RELATIVE SIGN OF NEUTRON HYNES 1 * 64.0 AND PROTON TRANSITION MATRIX ELEMENTS IN BERNSTEIN (p,p') REACTIONS . 630 A STUDY OF PROTON INELASTIC SCATTERING AT CAREY 1 59.0 0° AND A SEARCH FOR GIANT MONOPOLE AND GIANT' HINTZ 2 0.0 MAGNETIC DIPOLE EXCITATIONS MCCLELLAND 3 0.0 MOSS 632 CAN PROTON DENSITY DIFFERENCES BE EXTRACTED BARLETT 1 0.0 FROM MEDIUM-ENERGY p-NUCLEUS ELASTIC-SCATTERING HOFFMANN DATA 642 REACTIVE CONTENT OF THE OPTICAL POTENTIAL — McGILL 1 46.3 PHASE 2 HOFFMANN 643 STRUCTURE OF STATES IN THE OXYGEN ISOTOPES AAS 1 * 20.0 VIA MEASUREMENTS OF THE SPIN DEPOLARIZATION HYNES 2 80.0 AND SPIN-ROTATION OBSERVABLES 644 TESTS OF THE POLARIZATION-ANALYZING POWER IGO 0.0 EQUALITY IN ELASTIC SCATTERING OF INTERMEDIATE- ENERGY PROTONS FROM NUCLEI July-December 1981 PROGRESS AT LAMPF 127 Los Alamos National Laboratory 649 •Be(p,n*) REACTION AT 650 MeV HOISTAD 1 * 85.9 2 0.0 654 MEASUREMENT OF THE SPIN-ROTATION PARAMETER Q HOFFMANN 0.0 FOR 800-MeV p + "0, "Ca, AND IMPb ELASTIC SCATTERING 658 STUDY OF THE SPIN-FLIP PROBABILITY FOR SEESTROM-MORRIS 0.0 ELASTIC AND INELASTIC SCATTERING FROM ODD- CAREY MASS NUCLEI MOSS DEHNHARD 660 MEASUREMENT OF POLARIZATION PARAMETERS GLASHAUSSER 0.0 FOR M1 TRANSITIONS IN THE •°Zr(p,p')«,Zr* AND "•Sn(p,p')11«Sn* REACTIONS AT 500 MeV 663 ELASTIC SCATTERING OF POLARIZED PROTONS FROM IGO 0.0 3H AND 3He AT INTERMEDIATE ENERGIES BLESZYNSKI 666 THE "C(p,p'n),2C REACTION AND THE GLASHAUSSER 0.0 SEARCH FOR COHERENT ISOBAR-HOLE RESONANCES WHITTEN 669 INVESTIGATION OF THE N = 28 NEUTRON SHELL SHERA 0.0 CLOSURE BY ELASTIC SCATTERING OF 800-MeV WOHLFAHRT POLARIZED PROTONS 670 CONTINUATION OF GIANT RESONANCE STUDIES MOSS 0.0 AT THE HRS CAREY ADAMS 685 SPIN CORRELATIONS IN THE REACTION BLESZYNSKI 0.0 p(3,d)p AT 500 MeV IGO 686 DETERMINATION OF NEUTRON TRANSITION DENSITIES HINTZ 0.0 IN "O AND 2MPb BY INELASTIC SCATTERING OF ~400-MeV PROTONS 687 MEASUREMENT OF THE SPIN-ROTATION PARAMETERS RAHBAR 0.0 IN 20,Pb AND IN "Ca AT 400 MeV 699 MEASUREMENTS OF SPIN-FLIP AND DEPOLARIZATION HINTZ 0.0 PARAMETERS FOR "NI(p,p')8,NI* (6+,T = 0) — A TEST OF THE SPIN-ORBIT FORCE IN NUCLEI AT 500 MeV 709 MEASUREMENTS OF ANN, A„, AND Atl GAZZALY 0.0 IN THE COULOMB INTERFERENCE REGION AT 650 AND PAULETTA 800 MeV TANAKA 710 A MEASUREMENT OF THE TRIPLE-SCATTERING BARLETT 0.0 PARAMETERS D, R, A, R', AND A' FOR HOFFMANN QUASI-ELASTIC SCATTERING AT 800 MeV 711 REACTIVE CONTENT OF THE OPTICAL POTENTIAL HOFFMANN 0.0 AT 500 MeV 712 INELASTIC PROTON SCATTERING ON «»Ca AND SEGEL 0.0 MTi — AN ATTEMPT TO IDENTIFY MESONIC EFFECTS AS THE CAUSE OF M1 QUENCHING 713 M1's, DELTAS, AND MEDIUM EFFECTS IN CROSS GLASHAUSSER 0.0 SECTIONS FOR MSr(p,p')MSr* AT 400 MeV 714 A SEARCH FOR THE GIANT ISOVECTOR MONOPOLE GLASHAUSSER 0.0 RESONANCE IN INELASTIC PROTON SCATTERING AT 0° 128 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 718 ENERGY DEPENDENCE OF THE TWO-NUCLEON KELLY 0.0 EFFECTIVE INTERACTION HYNES 720 RECOILLESS DELTA PRODUCTION IN THE REACTION MORRIS 0.0 ,3 C(p,d)"CA McGILL 721 MEASUREMENT OF THE PROTON POLARIZATION AAS 0.0 OBSERVABLES IN 'LI(p,p')'U AND THE TEST OF THE BLESZYNSKI REACTION THEORY AT INTERMEDIATE ENERGIES 722 MEASUREMENT OF CROSS SECTIONS AND ANALYZING HARVEY 0.0 POWERS FOR ELASTIC AND INELASTIC SCATTERING OF SEESTROM-MORRiS 400-500-MeV PROTONS FROM "C 729 RADIATIVE CAPTURE OF POLARIZED PROTONS BY KOVASH 0.0 DEUTERONS AT 500-800 MeV ISOTOPE PRODI ;TION AND RADIATION-EFFECTS FACILITY (ISORAD) Exp. No. Till* Spokesman •=Complete Hours 82 184 PRODUCTION OF Sr O'BRIEN 1 * 0.0 210 ISOTOPE PRODUCTION FACILITY IRRADIATION O'BRIEN 1 * 0.0 VANADIUM, MOLYBDENUM, AND LANTHANUM TARGETS 211 NEUTRON IRRADIATION OF COPPER SINGLE CRYSTALS GREEN 1 * 0.0 267 PREPARATION OF RADIOISOTOPES FOR MEDICINE O'BRIEN 1 15652.3 AND THE PHYSICAL SERVICES USING THE LAMPF ISOTOPE PRODUCTION FACILITY 407 THE EFFECT OF DISLOCATION VIBRATION ON VOID SOMMER 3 0.0 GROWTH IN METALS DURING IRRADIATION PHILLIPS 725 THE EFFECT OF RARE-EARTH ADDITIONS ON DAVIDSON 1 0.0 RADIATION DAMAGE IN ALLOY HT-9 (FERRITIC/MARTENSITIC) WECHSLER ALLOY STEEL SOMMER LOW-ENERGY PION (LEP) Exp. Phase No. Btam No. Title Spokesman *=Complete Hours 2 TOTAL PION CROSS SECTIONS JAKOBSON 1 * 0.0 2 * 663.4 25 PION DOUBLE-CHARGE-EXCHANGE REACTION BUHMAN 1 * 0.0 2 * 681.2 3 * 268.2 28 STUDIES OF THE n+,n° REACTION YAVIN 1 * 195.0 29 ELASTIC SCATTERING OF n+ AND n" AT 10-30 MeV PREEDOM 1 * 0.0 2 * 0.0 July-December 1981 PROGRESS AT LAMPF 129 Los Alamos National Laboratory 35 CLUSTER EFFECTS IN NUCLEAR PION CAPTURE ZIOCK 297.5 SO RADIATIVE PION CAPTURE IN LIGHT NUCLEI CROWE 1 * 0.0 ROWE 2 * 460.3 54 ELASTIC SCATTERING OF MESONS IN THE ENERGY PREEDOM 1 * 264.6 RANGE 20-60 MeV 2 * 707.4 67 DEVELOPMENT OF PION BEAM-MONITORING DROPESKY 1 * 0.0 TECHNIQUES 2 * 87.5 79 CALIBRATION OF THE PION BEAM TRANSPORT PHILLIPS 1 • 0.0 SYSTEMS AND A PION BEAM MONITOR 86 SCATTERING OF 20-50-MeV n* BY HYDROGEN NAGLE 1 * 0.0 AND DEUTERIUM 2 * 728.0 102 EXCITATION FUNCTIONS AND ANGULAR DISTRIBU MARKOWITZ 1 * 0.0 TION RECOIL STUDIES OF SIMPLE PION-INDUCED NUCLEAR REACTIONS 121 PION-INDUCED NUCLEAR REACTIONS SEGEL 1 * 0.0 2 * 150.0 122 PIONIC ATOM X RAYS AND NUCLEAR DISTRIBUTIONS KUNSELMAN 1 * 0.0 123 NUCLEAR STRUCTURE EFFECTS IN PION-INDUCED KAROL 5 25.0 NUCLEAR REACTIONS 131 A STUDY OF THE n+ + d - p + p REACTION AT PION PREEDOM 1 * 0.0 ENERGIES 10-60 MeV 2 ' 260.0 140 STUDY OF THE (ir^.d) REACTION WITH AN INTRINSIC BARNES 1 * 0.0 GERMANIUM DETECTOR 2 * 385.0 3 * 0.0 144 SEARCH FOR THE C-VIOLATING DECAY IT0 + 3y HIGHLAND 1 * 333.0 MACEK 162 STUDIES OF THE (n\n°) REACTION ON LIGHT YAVIN 1 * 0.0 ELEMENTS ALSTER 164 PION TOTAL CROSS-SECTION MEASUREMENTS WITH FISHER 1 * 88.0 AN ORIENTED '"Ho TARGET MARSHAK 170 STUDY OF REACTION "C(n\n°),:>N ALSTER 0.0 (GROUND STATE) 180 ELASTIC AND INELASTIC n+-NUCLEUS SCATTERING EISENSTEIN 1 * 0.0 AT 25, 50, AND 75 MeV 2 * 191.3 181 MEASUREMENTS OF THE n"p - n°n ANGULAR ALSTER 1 * 346.0 DISTRIBUTION AT LOW ENERGIES AND CALIBRATION BOWMAN 2 * 859.2 OF THE TT° SPECTROMETER 190 A PRECISION MEASUREMENT OF THE n" n° ZIOCK 1 0.0 MASS DIFFERENCE 191 n+ NUCLEUS INELASTIC SCATTERING TO GIANT HALPERN 1 * 0.0 RESONANCES 2 * 292.7 3 * 484.4 4 * 284.4 209 PION INTERACTIONS IN NUCLEAR EMULSIONS BRADBURY 1 * 0.0 ALLRED 130 PROGRESS AT LAMPF July-Oecembar 1981 Los Alamos National Laboratory 234 A STUDY OF THE INELASTIC PION SCATTERING GOTOW 1 * 436.3 REACTION AT PION ENERGIES 10-100 MeV 247 DISTRIBUTION OF PRODUCTS FROM INTERACTIONS ORTH 35.6 OF STOPPED tr WITH SEVERAL MEDIUM- AND HEAVY- 59.5 MASS NUCLEI 284 MEASUREMENT OF THE 3He(TT,n=)3He ANGULAR COOPER 209.0 DISTRIBUTION WHITNEY 0.0 293 STUDY OF THE DOMINANT REACTION MODES FOR SEGEL 151.0 PIONS INTERFACING WITH COMPLEX NUCLEI 295 STUDY OF THE PION-DEUTERON SINGLE-CHARGE- BOWMAN 1 0.0 EXCHANGE REACTION d(n-,n°)2n MOINESTER + 299 AN INVESTIGATION OF THE REACTION (n*,n + p) ZIOCK 1 * 0.0 2 * 960.1 3 * 0.0 303 A SURVEY OF PION SINGLE-CHARGE-EXCHANGE JACKSON 1 * 152.8 SCATTERING USING BACK-ANGLE GAMMA 2 * 290.9 SPECTROSCOPY 3 • 304.0 315 HIGH-RESOLUTION STUDY OF THE (n\2p) REACTION WHARTON 1 * 0.0 2 * 338.1 3 • 662.4 316 n--NUCLEUS ELASTIC SCATTERING BETWEEN SETH 1 * 699.6 20 AND 50 MeV BURLESON 2 * 0.0 320 A COMPARISON OF (n\xn) AND (ir.xn) CHURCH 3 * 33.0 REACTIONS 4 0.0 322 SYSTEMATIC STUDY OF PION-INELASTIC BERTRAND 1 * 877.1 SCATTERING AT ENERGIES BELOW 100 MeV GOTOW 324 PRECISION MEASUREMENT OF RATIOS OF CERTAIN HALPERN 1 * 118.6 LIGHT ELEMENT PION EXCITATION FUNCTIONS 333 ni-NUCLEAR ELASTIC SCATTERING AT ENERGIES GOTOW 1 * 512.2 BETWEEN 50 AND 100 MeV 348 STUDY OF GIANT RESONANCES WITH RADIATIVE CROWE 1 * 761.7 PION CAPTURE ON MEDIUM-Z NUCLEI AT LEP 349 NUCLEAR REACTIONS OF "'I WITH PIONS PORILE 25.0 28.0 350 STUDY OF PION-ABSORPTION MECHANISMS IN SEGEL 225.8 NUCLEI SCHIFFER 388 LOW-ENERGY PION ELASTIC SCATTERING FROM HOLT 392.2 THE PROTON AND DEUTERON AT 180° 393 ANGULAR DISTRIBUTION MEASUREMENTS OF THE ALSTER 1 279.8 PION SINGLE-CHARGE-EXCHANGE REACTION ON "C MOINESTER 401 STUDY OF THE ISOBARIC ANALOG CHARGE-EXCHANGE BOWMAN 1 * 357.1 REACTION '»N(nV)1»0 COOPER 2 0.0 412 SEARCH FOR ANALOG STATE TRANSITIONS IN BAER 1 * 270.6 July-December 1981 PROGRESS AT LAMPF 131 Los Alamos National Laboratory 415 TWO-NUCLEON-OUT PRODUCTS FROM STOPPED ir ORTH 121.6 INTERACTIONS 416 STUDY OF FAST PION-INDUCED FISSION OF URANIUM DROPESKY 15.0 465 RADIOCHEMICAL STUDY OF PION SINGLE CHARGE RUNDBERG 1J.0 EXCHANGE 53.4 483 MEASUREMENT OF THE ANGULAR DEPENDENCE OF HOLT 478.3 TENSOR POLARIZATION IN THE 487 MEASUREMENT OF THE NUCLEAR RESONANCE REIDY 1 ' 202.8 EFFECT IN SOME PIONIC ATOMS LEON 523 STUDY OF uC(n\n°)"N REACTION GOODMAN 1 103.4 BAER 2 0.0 524 STUDY OF THE ISOVECTOR TERMS IN n-NUCLEUS BAER 1 243.9 INTERACTIONS WITH (n+,n°) REACTIONS BOWMAN 0N ».42..«.4.Ca AND ,,2.,i..,MSn CVERNA 525 EXCITATION OF ISOVECTOR TRANSITIONS WITH KING 1 9.2 PION SINGLE CHARGE EXCHANGE ON ,2C MOINESTER 527 STUDY OF THE 10B(n-,n°)'°B REACTION BAER 1 0.0 BOWMAN 536 EFFICIENCY MEASUREMENTS FOR n+ IDENTIFICATION GUTBROD 1 * 106.7 IN THE PLASTIC BALL DETECTOR 541 A SEARCH FOR NUCLEAR CRITICAL OPALESCENCE COOPER 1 * 773.7 USING THE REACTION 4°Ca(n+,2v) 543 A PRODUCT RECOIL STUDY OF THE (rt'.n'n) REACTION CARETTO 1 7.8 544 SEARCH FOR A FAST FISSION PROCESS WILHELMY 1 * 48.0 2 76.0 553 STUDY OF TARGET THICKNESS EFFECTS IN THE RUNDBERG 1 * 69.0 CROSS-SECTION MEASUREMENT OF THE PION 2 14.0 SINGLE-CHARGE-EXCHANGE REACTION ,3C(n+,rt°),;1N (g.S.) FROM 50 TO 350 MeV 557 EXPOSURE, IN A PARASITIC MODE, OF A 3-cm BY COWSIK 0.0 3-cm BY 1-cm STACK OF SOLID-TRACK DETECTORS TO A n" BEAM 561 n*-NUCLEAR ELASTIC SCATTERING AT ENERGIES BLECHER 241.0 BETWEEN 30 AND 80 MeV OBENSHAIN HYNES 567 A STUDY OF THE IT* + d - p + p REACTION AT PION GOTOW 0.0 ENERGIES 5-200 MeV MINEHART RITCHIE 576 STUDY OF THE (n*,2p) AND (n*,2p) REACTIONS ROOS 0.0 ON THE ISOTOPIC PAIRS "0-"0 AND PREEDObt "Ca-"Ca CHANT 607 STUDY OF ISOVECTOR GIANT RESONANCES WITH ALSTER 259.5 PION CHARGE EXCHANGE BAER 0.0 BOWMAN 611 EXCITATION FUNCTIONS OF THE FOUR HOGAN 0.0 ""TeOiWn) REACTIONS 132 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 650 A SEARCH FOR NEUTRINO MIXING VIA NONEXPONENTIAL BOWMAN 249.0 n - uv DECAY MOINESTER 675 NUCLEAR DISTRIBUTIONS FROM THE STUDY OF THE KUNSELMAN 0.0 2p STATES OF PIONIC ATOMS M 676 STUDY OF PION ABSORPTION ON NI AT CHANT 0.0 T, = 160 MeV REDWINE ROOS 688 STUDY OF THE MASS AND ENERGY DEPENDENCE LEITCH 0.0 OF LOW-ENERGY PION SINGLE CHARGE EXCHANGE COOPER 728 STUDY OF PION CHARGE-EXCHANGE MECHANISMS QIESLER 0.0 BY MEANS OF ACTIVATION TECHNIQUES LINE B (Line-B) Exp. Phase No. Beam No. Titlt Spokesman *=Complete Hours 179 DIFFERENTIAL PRODUCTION CROSS SECTIONS OF BOWMAN 1 ' 1341.4 MULTIPLY CHARGED FRAGMENTS IN PROTON AND PION-INDUCED SPALLATION OF LIGHT NUCLEI LINE X BEAM STOP (Line-X-BS) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 184 PRODUCTION OF "Sr O'BRIEN 0.0 NEUTRINO AREA (Neutrino A) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 31 A NEUTRINO EXPERIMENT TO TEST MUON NEMETHY 1 * 6713.2 CONSERVATION 2 * 1097.4 148 NEUTRINO ELECTRON ELASTIC SCATTERING AT CHEN 1 * 0.0 LAMPF (A FEASIBILITY STUDY) REINES 2 ' 1132.0 225 A STUDY OF NEUTRINO ELECTRON ELASTIC SCATTERING CHEN 1 47.0 254 FEASIBILITY STUDY FOR THE MEASUREMENT OF THE FIREMAN 1 * 1026.0 INELASTIC NEUTRINO SCATTERING CROSS SECTIONS IN"K 559 SEARCH FOR NEUTRINO OSCILLATIONS AND DUONG-VAN 1 0.0 VIOLATION OF LEPTON-NUMBER CONSERVATION PHILLIPS July-December 1981 PROGRESS AT LAMPF 133 Los Alamos National Laboratory 609 ANTINEUTRINO OSCILLATION EXPERIMENTS AT LAMPF KRUSE 1 0.0 638 A SEARCH FOR OSCILLATIONS USING MUON-NEUTRINOS DOMBECK 1 0.0 645 A SEARCH FOR NEUTRINO OSCILLATIONS AT LING 1 0.0 LAMPF ROMANOWSKI 2 0.0 647 A NEUTRON OSCILLATION EXPERIMENT AT LAMPF ELLIS 0.0 PROTON IRRADIATION PORT (PIP) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 302 800-MeV PROTON IRRADIATION OF AN ALUMINUM GREEN 1 * 326.6 SAMPLE 327 PIP, PROTON IRRADIATION PORT WILSON 16.9 PION PARTICLE PHYSICS (P3) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 32 PRECISION MEASUREMENT OF THE PROCESSES McFARLANE 1 * 0.0 MACEK 2 * 1092.2 r^ — n° + E1 + v MINEHART 1 * 0.0 34 ELASTIC SCATTERING OF n* ON DEUTERONS NEFKENS 1 * 0.0 58 MEASUREMENT OF n" + p - y + n FITZGERALD 67 DEVELOPMENT OF PION BEAM MONITORING DROPESKY 1 * 0.0 TECHNIQUES 2 * 220.2 3 6.3 79 CALIBRATION OF THE PION BEAM TRANSPORT PHILLIPS 1 * 0.0 SYSTEMS AND A PION BEAM MONITOR 80 FORWARD ELASTIC SCATTERING OF n+ AND ir FROM PHILLIPS 1 * 0.0 i2C i3C i«0 4oCa_ AND !oaPb 2 * 528.8 82 INVESTIGATION OF PION-INDUCED REACTIONS ON PHILLIPS 1 • 425.3 LIGHT ELEMENTS WITH THREE PARTICLES IN THE FINAL STATE 90 A TEST OF THE REVERSAL INVARIANCE IN SINGLE- SHERMAN 1 * 0.0 PION PHOTO PRODUCTION THROUGH A STUDY OF SHIVELY 2 * 806.9 RECIPROCITY IN THE REACTIONS ir-'He S yt GLODIS 3 (AND ITS INVERSE) AND n + t - Hev (AND ITS SPENCER INVERSE) WADLINGER NEFKENS 99 MEASUREMENT OF THE CROSS SECTION FOR REBKA 1 * 0.0 n" + p - n" + TT+ + n WITH A MAGNETIC GRAM 2 * 646.0 SPECTROMETER 134 PROGRESSATLAMPF July-December 1981 Los Alamos National Laboratory 102 EXCITATION FUNCTIONS AND ANGULAR DISTRIBU MARKOWITZ 0.0 TION RECOIL STUDIES OF SIMPLE PION-INDUCED NUCLEAR REACTIONS 103 SPALLATION YIELD DISTRIBUTIONS FOR PION HUDIS 0.0 INTERACTIONS WITH COMPLEX NUCLEI 295.7 104 PROPOSAL FOR LAMPF EXPERIMENT: STUDIES OF PATE 0.0 THE PROTON- AND PION-INDUCED FISSION OF 118.7 MEDIUM-MASS NUCLIDES 118 FRAGMENT EMISSION FROM PION INTERACTIONS PORILE 0.0 WITH COMPLEX NUCLEI 97.0 119 CROSS SECTIONS OF SIMPLE NUCLEAR REACTIONS KAUFMAN 27.8 INDUCED BY n-MESONS 186.8 120 MEASUREMENT OF THE POLARIZATION ASYMMETRY NEFKENS 870.2 AND THE DIFFERENTIAL CROSS SECTION OF FITZGERALD 90.3 PION-NUCLEON CHARGE EXCHANGE FROM 160-500 MeV 121 PION-INDUCED NUCLEAR REACTIONS SEGEL 1 * 0.0 2 * 0.0 123 NUCLEAR STRUCTURE EFFECTS IN PION-INDUCED KAROL 1 " 0.0 NUCLEAR REACTIONS 2 * 75.0 3 * 135.1 4 * 0.0 5 21.0 144 SEARCH FOR THE C-VIOLATION DECAY IT0 + 3y HIGHLAND 2 * 602.1 MACEK 153 INVESTIGATION OF NUCLEAR GAMMA-RAYS RESULTING EISENSTEIN 1 * 0.0 FROM IN-FLIGHT PION AND PROTON REACTIONS 154 ELASTIC SCATTERING OF n+ AND n" FROM THE MINEHART 1 * 7.2 HELIUM ISOTOPE MCCARTHY 2 * 316.0 181 MEASUREMENTS OF THE np - n°n ANGULAR ALSTER 2 * 204.3 DISTRIBUTION AT LOW ENERGIES AND CALIBRATION BOWMAN OF THE n° SPECTROMETER 195 NUCLEAR RESONANCE EFFECT IN PIONIC ATOMS LEON 2 * 0.0 REIDY 3 " 163.1 201 n+d - 2d REACTION AT 100-500 MeV MINEHART 1 * 338.0 214 PIONIC X-RAY ABSOLUTE YIELDS AS A FUNCTION HARGROVE 1 * 199.1 OFZ LEON 221 PRECISION MEASUREMENT OF THE DECAY RATE HOFFMAN 1 * 351.5 FOR THE DALITZ DECAY MODE OF THE n° MESON 222 MEASUREMENT OF THE DECAY RATE FOR n° - e+e~ MISCHKE 1 * 945.8 247 DISTRIBUTION OF PRODUCTS FROM INTERACTIONS ORTH 2 * 28.0 OF STOPPED n- WITH SEVERAL MEDIUM- AND HEAVY- MASS NUCLEI 248 STUDY OF THE (n,nn), (n,A), (n,Ba), AND (n,n) KALLNE 674.4 REACTIONS IN "He AND "Li BY MEASURING MCCARTHY RECOIL SPECTRA GUGELOT July-December 1981 PROGRESS AT LAMPF 135 Los Alamos National Laboratory 283 CHARG ED-PARTICLE EMISSION FOLLOWING u" CAPTURE KRANE 1 * 31.0 SHARMA 286 PROTON AXIAL TOMOGRAPHY HANSON 1 * 345.5 304 STUDY OF THE AUGER PROCESS IN PIONIC ATOMS LEON 1 * 78.6 MAUSNER + 309 INCLUSIVE n AND n" DOUBLE CHARGE EXCHANGE REBKA 594.0 ON "O AND "Ca 319 DETERMINING THE MECHANISM FOR MULTINUCLEON LIND 283.0 AND CLUSTER REMOVAL IN 200-MeV n-NUCLEAR INTERACTIONS 320 A COMPARISON OF (n*,xn) AND (ir.xn) REACTIONS CHURCH 57.8 170.1 337 MEASUREMENT OF THE CROSS SECTION FOR REBKA 999.8 irp - n-n+n AT 200 AND 229 MeV GRAM 349 NUCLEAR REACTIONS OF 127l WITH PIONS PORILE 1 * 74.5 2 * 55.2 3 9.0 358 ELASTIC SCATTERING OF PION FROM DEUTERIUM MINEHART 1 * 514.0 J 363 MEASUREMENT OF n + p ELASTIC SADLER 1 * 700.5 SCATTERING NEFKENS 2 * 844.5 373 A COMPARISON OF RESIDUAL NUCLEI YIELDS REIDY 1 * 94.1 FROM n" ABSORPTION IN "2Cd (GROUND STATE) LEON AND "2D (FIRST EXCITED STATE) 390 A STUDY OF INCLUSIVE INELASTIC PION SCATTERING JACKSON 1 * 453.0 NEAR THE 6(3/2,3/2) RESONANCE 394 APPLICATION OF PROTON COMPUTED TOMOGRAPHY HANSON 1 * 195.3 396 COMPARISON OF MEASURED PIONIC ATOM CASCADE REIDY 1 * 110.9 INTENSITIES WITH THEORETICAL INTENSITIES OBTAINED USING PARAMETERS FROM MUONIC ATOM STUDIES 400 SEARCH FOR THE RARE DECAY u+ - 6*6*8" DUONG-VAN 1 * 156.8 HOFFMAN 404 A KINEMATICALLY COMPLETE STUDY OF THE HAMM 1 • 401.5 (n.n'p) REACTION ON ,eO ABOVE THE RESONANCE SWENSON BY DETECTING PIONS AND PROTONS IN COINCIDENCE 416 STUDY OF FAST PION-INDUCED FISSION OF DROPESKY 1 * 141.0 URANIUM 2 * 17.0 3 * 26.2 4 0.0 420 DEVELOPMENT OF A HIGH-RESOLUTION LIQUID- FLYNN 0.0 ARGON CHARGED-PARTICLE DETECTOR OF MEDIUM- ENERGY PARTICLES 439 PARTICLE GAMMA-RAY COINCIDENCE STUDIES FROM LIND 239.0 n-NUCLEAR REACTIONS 0.0 + 455 HIGH-PRECISION STUDY OF THE M DECAY SPECTRUM ANDERSON 421.3 136 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 458 THE EXCITATION FUNCTION FOR THE SINGLE-CHARGE- KAUFMAN 80.4 EXCHANGE REACTION "sCu(n-,n°)MNI 459 CROSS-SECTION MEASUREMENTS OF THE VIEIRA 96.0 "NfaWPO (GROUND STATE) REACTION 465 RADIOCHEMICAL STUDY OF PION SINGLE CHARGE RUNDBERG 1 * 99.1 EXCHANGE 2 104.4 466 NUCLEAR CONFIGURATION OF INDIVIDUAL CORE- FUNSTEN 1 * 219.6 COUPLED STATES IN 2MBI FROM INELASTIC PLENDL n! SCATTERING 469 STUDY OF THE 9'Zr(n\n°p)9°Zr MoGILL 1 0.0 CHARGE-EXCHANGE REACTION HOFFMANN 480 DISCRETE STATES FROM PION DOUBLE CHARGE ZEIDMAN 1 0.0 EXCHANGE ON HEAVY NUCLEI 500 FISSION FRAGMENT DISTRIBUTIONS IN FAST RUNDBERG 1 * 72.2 23i PION-INDUCED FISSION OF U 2 0.0 513 IT* QUASI-FREE SCATTERING FROM THE HELIUM MCCARTHY 1 " 0.0 ISOTOPES MINEHART 2 * 557.7 543 A PRODUCT RECOIL STUDY OF THE CARETTO 1 96.5 (TTi.n^n) REACTION 553 STUDY OF TARGET THICKNESS EFFECTS IN THE RUNDBERG 1 * 61.3 CROSS-SECTION MEASUREMENT OF THE PION SINGLE-CHARGE-EXCHANGE REACTION '3C(TT\TT°),3N (g.s.) FROM 50 TO 350 MeV 555 TOTAL CROSS-SECTION MEASUREMENTS OF THE IMANISHI 1 * 139.0 SINGLE-CHARGE-EXCHANGE REACTION VIEIRA "C^.nT'N (g.s.) 562 STUDY OF THE PION ABSORPTION MECHANISM JACKSON 1 * 428.0 SCHIFFER THROUGH THE A(TT,P)X REACTION AT T„ = 500 MeV McKEOWN 1 * 436.5 564 STUDY OF SMALL-ANGLE «He(Tr,TT*) REACTION) ORTH 1 15.2 595 AN ON-LINE Y-RAY STUDY OF PION-INDUCED VIEIRA SINGLE-NUCLEON REMOVAL REACTIONS ON "C AND 'BCa 603 SEARCH FOR DELTAS IN A COMPLEX NUCLEUS BY TURKEVICH 2 0.0 A RADIOCHEMICAL TECHNIQUE 611 EXCITATION FUNCTIONS OF THE FOUR HOGAN 8.5 ""Tefn'.iT*!!) REACTIONS 614 STUDIES OF SCALAR AND VECTOR PARTS OF THE FUNSTEN 0.0 n-n INTERACTION BY MEASURING NUCLEAR DEEXCITATION v-RAY CORRELATION FOLLOWING INELASTIC PION SCATTERING 617 A STUDY OF THE (3/2,3/2) RESONANCE IN LIGHT ZIOCK 0.0 NUCLEI 628 STUDY OF THE (n,np) REACTION AND QUASI- ASHERY 0.0 FREE SCATTERING IN 'He July-December 1981 PROGRESS AT LAMPF 137 Los Alamos National Laboratory 673 MEASUREMENTS OF THE ANGULAR DEPENDENCE HOLT 0.0 OF TENSOR POLARIZATION IN THE ,H(n*,ir)J'H" REACTION AT T, = 180 AND 256 MeV 674 MEASUREMENTS OF PION-NUCLEUS ELASTIC AND BURLESON 0.0 DOUBLE-CHARGE EXCHANGE SCATTERING AT MORRIS ENERGIES ABOVE 300 MeV 682 SEARCH FOR DIBARYON RESONANCES IN THE IMAI 0.0 n REACTION nd - pnn AT P L = 200 TO 600 MeV/c GREENE 689 A. NEUTRON COUNTER CALIBRATION USING NEFKENS 0.0 TAGGED NEUTHONS FROM THE REACTION FITZGERALD -"d - nn. B. FEASIBILITY STUDY: MEASUREMENT OF THE DIFFERENTIAL CROSS SECTION FOR --d - nn TO TEST CHARGE SYMMETRY AND ISOSPIN INVARIANCE 705 STUDY OF PION ABSORPTION IN 3He ON AND ABOVE ASHERY 0.0 THE (3,3) RESONANCE* 728 STUDY OF PION CHARGE-EXCHANGE MECHANISMS GIESLER 0.0 BY MEANS OF ACTIVATION TECHNIQUES 730 PION PRODUCTION IN PION-INDUCED AND PION- SAGHAI 0.0 NUCLEUS INTERACTIONS PREEDOM DROPESKY RADIATION DAMAGE A-1 (RADAMAGE-1) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 302 800-MeV PROTON IRRADIATION OF AN ALUMINUM SAMPLE GREEN 1 * 0.0 545 FUSION MATERIALS NEUTRON IRRADIATIONS - BROWN 1 224.8 A PARASITE EXPERIMENT STOPPED MUON CHANNEL (SMC) Exp. Phase No. Beam No. Title Spokesman '-Complete Hours NUCLEAR STRUCTURE PHYSICS USING STOPPED SHERA 1 * 0.0 MUONS 2 * 617.3 12 MUONIC X RAYS AND NUCLEAR CHARGE POWERS 1 * 173.0 DISTRIBUTIONS KUNSELMAN 2 * 141.9 37 ULTRAHIGH-PRECISION MEASUREMENTS OF MUONIUM HUGHES 1 * 0.0 GROUND-STATE ENERGY LEVELS, HYPERFINE CRANE 2 * 940.4 STRUCTURE INTERVAL AND MUON MAGNETIC MOMENT 51 TECHNIQUES FOR MATERIALS IDENTIFICATION AND MALANIFY 1 * 119.3 ANALYSIS 60 CHEMICAL EFFECTS IN THE CAPTURE OF NEGATIVE KNIGHT 1 * 0.0 MESONS IN MATTER SCHILLACI 2 * 451.5 138 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 76 SEARCH FOR MUONIUM-ANTIMUONIUM TRANSITION CHANG 0.0 KANE 85 GAMMA-NEUTRINO CORRELATION AFTER NEGATIVE WELSH 193.6 MUON CAPTURE 100 TISSUE CHEMICAL ANALYSIS WITH MU-MESIC X RAYS HUTSON 1 * 0.0 2 * 167.0 101 FEASIBILITY STUDIES. MEASUREMENT OF MUONIC BOEHM FS* 103.0 X RAYS AND NUCLEAR GAMMA RAYS WITH CRYSTAL LU DIFFRACTION SPECTROMETERS AT LAMPF 122 PIONIC ATOM X RAYS AND NUCLEAR DISTRIBUTIONS KUNSELMAN 2 * 64.8 142 NEGATIVE MUON-INDUCED FISSION IN THE HUIZENGA 1 * 0.0 ACTINIDE ELEMENTS 2 * 520.3 163 INVESTIGATION OF CHANGES IN CHARGE PERKINS 1 * 0.0 DISTRIBUTIONS FOR NUCLEI NEAR Z = 28 BY SHERA ELECTRON SCATTERING AND MUONIC X RAYS 165 MUONIUM FORMATION IN HELIUM AND OTHER HUGHES 1 * 0.0 RARE GASES 166 MUONIC X RAYS AND NUCLEAR CHARGE POWERS 1 * 0.0 DISTRIBUTIONS ELECTRIC QUADRUPOLE MOMENTS OF „Ho'M AND ,,Ta"" 173 PHYSICS OF THE PION AND THE PIONIC ATOM BOEHM 600.9 VOGEL 309.6 175 SEARCH FOR THE FORMATION OF MUONIC HELIUM HUGHES 0.0 (aire) 206 SEARCH FOR THE 2S METASTABLE STATE OF HUGHES 1 * 497.0 MUONIC HYDROGEN EGAN 213 MUON TRANSFER STUDY SHERA 1 * 50.9 STEFFEN 240 ISOTOPE AND ISOTONE SHIFTS IN THE SHERA 1 * 294.1 1f,„ SHELL WOHLFAHRT 266 TRAPPING OF POSITIVE MUONS AT DEFECTS IN GAUSTER 1 * 223.0 METALS HEFFNER 2 * 106.1 3 * 9.0 268 MEASUREMENT OF THE GROUND-STATE HYPERFINE SOUDER 1 * 518.6 STRUCTURE INTERVAL OF THE MUONIC HELIUM HUGHES ATOM (aire-) 276 PERTURBED CIRCULAR POLARIZATION OF MUONIC YAMAZAKI 1 * 0.0 XRAYS 2 * 183.8 3 * 235.1 277 MUONIC X-RAY ANALYSIS OF CORE SAMPLES FROM ALLRED 33.0 OIL-BEARING FORMATIONS 283 CHARGED-PARTICLE EMISSION FOLLOWING u" KRANE 138.3 CAPTURE SHARMA 88.6 288 STUDIES OF u" CAPTURE PROBABILITIES FOR NAUMANN 180.1 SOLID-STATE SOLUTIONS July-December 1981 PROGRESS AT LAMPF 139 Los Alamos National Laboratory 292 NEUTRON EMISSION FROM MUON-INDUCED REACTIONS HUIZENQA 1 * 196.2 ON ACTINIDE ELEMENTS 2 * 138.3 297 A BICENTENNIAL PROPOSAL TO STUDY THE BEHAVIOR BROWN 1 * 144.1 OF POSITIVE MUONS IN SOLIDS 2 * 137.1 3 * 47.1 328 MEASUREMENT OF THE DECAY RATE AND PARITY BOWMAN 1 * 1666.3 + VIOLATING ASYMMETRY FOR M* - e Y COOPER 330 FUNDAMENTAL MUONIC X-RAY MEASUREMENTS OF HUTSON 1 * 90.4 INTEREST TO MATERIALS ANALYSIS YATES-WILLIAMS 2 * 67.8 331 FAST MUON REACTIONS WITH "C, "Tl, AND MNI ORTH 1 • 97.2 2 * 78.0 334 NUCLEAR CHARGE PARAMETERS OF "Ca AND STABLE SHERA 1 * 162.4 CADMIUM AND TELLURIUM ISOTOPES WOHLFAHRT 2 ' 170.3 335 MONOPOLE AND QUADRUPOLE CHARGE DISTRIBUTIONS SHERA 1 * 298.7 IN THE SAMARIUM AND GADOLINUM ISOTOPES YAMAZAKI 2 0.0 344 HIGHER PRECISION MEASUREMENT OF MUON HUGHES 1 * 425.6 MAGNETIC MOMENT AND OF MUONIUM hfs INTERVAL 357 MUONIC X-RAY SPECTRA OF GASES: 1. DENSITY AND KNIGHT 145.1 ADMIXTURE EFFECTS 364 SEARCH FOR THE EXCITED 2S STATE OF MUONIUM EGAN 535.8 DENISON 167.7 HUGHES 371 MUONIC X-RAY SPECTRA OF GASES: 2. CAPTURE HUTSON 122.7 PROBABILITIES IN MIXTURES 374 M" CAPTURE PROBABILITIES FOR SELECTED SOLID SCHILLACI 1 * 161.7 BINARY COMPOUNDS 375 MSR STUDY OF DIFFUSION IN METALS IN THE SCHILLACI 1 * 194.6 PRESENCE OF PARAMAGNETIC IONS 2 * 287.0 3 * 45.0 377 INVESTIGATION ON THE EFFECT OF GRAIN SIZE IN REIDY 28.0 MUON CAPTURE IN INHOMOGENEOUS SYSTEMS 382 MSR INVESTIGATION OF THE EFFECTS OF IMPURITIES KOSSLER 111.4 + ON THE TRAPPING AND DIFFUSION OF M PARTICLES IN bcc METALS 400 SEARCH FOR THE RARE-DECAY DUONG-VAN 1 54.4 HOFFMAN 2 * 410.9 408 MACROSCOPIC DIFFUSION STUDIES IN METALS HEFFNER 1 * 81.0 LEON 414 BONE CALCIUM ASSAY WITH MUONIC X RAYS - HUTSON 1 * 118.6 SIGNAL/NOISE AND REPRODUCIBILITY STUDIES REIDY 421 SENSITIVE SEARCH FOR u" - e CONVERSION SOUDER 1 42.0 FRANKEL HUGHES + 427 MAGNET RESONANCE STUDIES OF M -ELECTRON ESTLE 1 * 253.3 DEFECT COMPLEXES IN NONMETALS 2 161.4 3 24.0 140 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory 436 NEGATIVE MUON SPIN ROTATION AND RELAXATION YAMAZAKI 196.2 IN MAGNETIC MATERIALS HAYANO 444 SEARCH FOR THE DECAY u - ey BOWMAN 0.0 HOFSTADTER 445 SEARCH FOR THE LfcPTON-FLAVOR-VIOLATING MATIS 54.4 DECAY v* - e+w BOWMAN 3 464 RADIATIVE MUON CAPTURE IN GASEOUS He WU 0.0 DUGAN HUGHES LU EGAN 491 EXPERIMENTAL DETERMINATION OF THE STRONG LEE 1 * 646.6 INTERACTION SHIFT IN THE 2p-1s TRANSITION 2 376.1 OF PIONIC DEUTERIUM AND HYDROGEN ATOMS 3 0.0 494 NUCLEAR CHARGE PARAMETERS OF THE STABLE HOEHN 10B.0 RUTHENIUM AND PALLADIUM ISOTOPES 499 MUON LONGITUDINAL AND TRANSVERSE RELAXATION DODDS 1 * 329.6 STUDIES IN SPIN-GLASS SYSTEMS MACLAUGHLIN 2 213.0 HEFFNER 3 0.0 529 PART 1: MEASUREMENT OF THE RESIDUAL MUON WU 1 " 136.0 POLARIZATION IN 3He MUONIC ATOM (A FEASIBILITY DUGAN 2 0.0 TEST FOR PART 2), AND PART 2: ANGULAR HUGHES 3 0.0 CORRELATIONS IN THE CAPTURE OF POLARIZED MUONS IN GASEOUS 3He 547 SEARCH FOR FAST MUONIUM IN VACUUM EGAN 1 * 231.4 HUGHES 2 * 144.0 KANE 3 * 100.1 552 ULTRAHIGH-PRECISION MEASUREMENTS ON HUGHES 0.0 MUONIUM EGAN 571 MUON SPIN-ROTATION STUDIES OF DILUTE DODDS 359.4 MAGNETIC ALLOYS HEFFNER SCHILLACI 594 PRECISION DETERMINATIONS OF SOME RELATIVE REIDY 93.0 MUONIC COULOMB CAPTURE RATIOS IN OXIDES OF DIFFERENT VALENCES 639 MUON SPIN-ROTATION STUDY OF MUON BONDING BOEKEMA 1 45.0 AND MOTION IN SELECT MAGNETIC OXIDES DENISON 640 TRANSVERSE AND LONGITUDINAL FIELD MSR DODDS 1 246.0 MEASUREMENTS IN SELECTED TERNARY METALLIC HEFFNER 2 0.0 COMPOUNDS MACLAUGHLIN 646 HYPERFINE STRUCTURE OF MUONIC 3He AND HUGHES 1 414.0 MUONIC 4He ATOMS EGAN 2 0.0 653 THE 241Am AND 2"Am MUONIC ATOM STUDIES SHERA 1 151.1 JOHNSON NAUMANN 693 INVESTIGATION OF THE TWO-PHOTON DECAY RATE REIDY 0.0 4 FROM THE (w He)+s STATE AS A FUNCTION OF PRESSURE July-December 1981 PROGRESS AT LAMPF 141 Los Alamos National Laboratory 697 NUCLEAR EXCITATION FOLLOWING MUON CAPTURE BUDICK 0.0 ON MEDIUM AND HEAVY NUCLEI 698 GROUND-STATE QUADRUPOLE MOMENTS OF STEFFEN 0.0 DEFORMED NUCLEI SHERA 707 STUDY OF TRANSFER EFFECTS IN MUON CAPTURE REIDY 0.0 IN GAS TARGETS HUTSON 715 ANALYSIS OF CHEMICAL COMPOSITION OF OOSTENS 0.0 ARCHAEOLOGICAL ARTIFACTS BY WAY OF SNOW MUONIC X RAYS 724 MEASUREMENT OF THE LAMB SHIFT IN MUONIUM EGAN 0.0 GLADISCH HUGHES 726 SEARCH FOR THE C-NONINVARIANT DECAY HIGHLAND 0.0 0 it - 3Y SANDERS 727 MEASUREMENT OF THE EFFICIENCY OF MUON JONES 0.0 CATALYSIS IN DEUTERIUM-TRITIUM MIXTURES AT HIGH DENSITIES SWITCHYARD LINE A BEAM STOP (SWY-LABS) Exp. Phate No. Beam No. Title Spoketman *=Complete Hours 105 NUCLEAR SPECTROSCOPY STUDIES OF PROTON- BUNKER INDUCED SPALLATION PRODUCTS 118 FRAGMENT EMISSION FROM PION INTERACTIONS PORILE WITH COMPLEX NUCLEI 269 800-MEV PROTON IRRADIATION OF METAL SAMPLES GREEN 381 ALUMINA CERAMIC RADIATION EFFECTS STUDY HARVEY 648 TEST OF EQUIPMENT FOR THE MEASUREMENT OF MILLER THE r- FOR THE MAGNETIC MOMENT AT BNL 652 TESTS OF PROTOTYPE SEMICONDUCTOR DETECTORS SKUBIC 0.0 THIN TARGET AREA (TTA) Exp. Phase No. Beam No. Title Spokesman *=Complete Hours 86 COUNTER EXPERIMENTS IN THE THIN TARGET AREA POSKANZER 1 * 0.0 2 * 743.0 3 * 1128.0 308 AN ATTEMPT TO MAKE DIRECT ATOMIC MASS BUTLER 1 5808.4 MEASUREMENTS IN THE THIN TARGET AREA POSKANZER 692 Ge DETECTOR LOW-LEVEL RADIATION-DAMAGE REEDY 0.0 EQUILIBRATION EXPERIMENT 142 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory APPENDIX D ACTIVE SPOKESMEN, INSTITUTIONS, AND EXPERIMENTS SPOKESMEN INSTITUTIONS EXPERIMENTS AAS, B. UNIV. OF CALIFORNIA, LOS ANGELES 643 ALSTER, J. TEL AVIV UNIV. 393, 607 ANDERSON, H. L. LOS ALAMOS 455 ANDERSON, R. E. UNIV. OF NORTH CAROLINA 535 ASHERY, D. TEL AVIV UNIV. 628 BAER, H. W. LOS ALAMOS 412, 523, 524, BAKER, F. T. UNIV. OF GEORGIA 356 BARLETT, M. UNIV. OF TEXAS, AUSTIN 632 BAUER, T. S. SACLAY 405 BENTON, E. V. UNIV. OF SAN FRANCISCO 171 BERTRAND, F. E. OAK RIDGE 399 BLANPIED, G. S. UNIV. OF SOUTH CAROLINA 475, 573 BLECHER, M. VPI/STATE UNIV. 561 BLESZYNSKI, M. UNIV. OF CALIFORNIA, LOS ANGELES 540, 616, 635 BOEKEMA, C. LOS ALAMOS 639 BONNER, B. E. LOS ALAMOS 635, 637 BOWMAN, J. D. LOS ALAMOS 295,401,412, BRADBURY, J. N. LOS ALAMOS 215 BRILL, A. B. BROOKHAVEN 244 BROWN, R. D. LOS ALAMOS 545, 554 BRYANT, H. C. UNIV. OF NEW MEXICO 586, 588 BUNKER, M. E. LOS ALAMOS 629 BURLESON, G. R. NEW MEXICO STATE UNIV. 386, 496, 558 BURNETT, D. S. CALTECH 161 BUSH, S. UNIV. OF NEW MEXICO 274, 275 BUTLER, G. W. LOS ALAMOS 308 CARETTO, A. A. CARNEGIE-MELLON UNIV. 543 CAREY, T. A. LOS ALAMOS 630 CARLINI, R. D. LOS ALAMOS 634 CHANT, N. S. UNIV. OF MARYLAND 576 CHEN, H. H. UNIV. OF CALIFORNIA, IRVINE 225 CHURCH, L. B. REED COLLEGE, OREGON 320 CLARK, D. A. UNIV. OF NEW MEXICO 588 COOPER, M. D. LOS ALAMOS 284, 401 CORNELIUS, W. D. LOS ALAMOS 474 COST, J. R. LOS ALAMOS 554 COTTINGAME, W. B. NEW MEXICO STATE UNIV. 598 COWSIK, R. WASHINGTON UNIV. 557 CVERNA, F. H. LOS ALAMOS 412, 524 DEHNHARD, D. UNIV. OF MINNESOTA 510, 580, 602 DENISON, A. B. UNIV. OF WYOMING 639 DEVRIES, R. M. LOS ALAMOS 591, 592 DICELLO, J. F. LOS ALAMOS 272 DIGIACOMO, N. LOS ALAMOS 591, 592 DODDS, S. A. RICE UNIV. 499, 571, 640 DOMBECK, T. W. UNIV. OF MARYLAND 638 DONAHUE, J. B. LOS ALAMOS 587 DROPESKY, B. J. LOS ALAMOS 416 DUGAN, G. COLUMBIA UNIV. 464, 529 DUONG-VAN, M. LOS ALAMOS 400, 559 EGAN, P. D. YALE UNIV. 464, 552, 646 ELLIS, R. J. LOS ALAMOS 647 ESTLE, T. L. RICE UNIV. 427 FAUBEL, W. LOS ALAMOS 579 FITZGERALD, D. H. UNIV. OF CALIFORNIA, LOS ANGELES 120 FLYNN, E. R. LOS ALAMOS 420 July-December 1981 PROGRESS AT LAMPF 143 Los Alamos National Laboratory SPOKESMEN INSTITUTIONS EXPERIMENTS FRANKEL, S. UNIV. OF PENNSYLVANIA 421 FUNSTEN, H. 0. COLLEGE OF WILLIAM & MARY R14 GAZZALY, M. M. UNIV. OF MINNESOTA 563 GEESAMAN, D. F. ARGONNE 565 GERACI, J. P. UNIV. OF WASHINGTON 384 GILLETTE, E. L. COLORADO STATE UNIV. 235 GILMORE, J. S. LOS ALAMOS 467 GLASHAUSSER, C. RUTGERS UNIV. 356, 531, 623, 626 GLASS, G. C. TEXAS A&M UNIV. 589 GOLDSTEIN, L. S. UNIV. OF CALIFORNIA, SAN FRANCISCO 380 GOODMAN, C. D. INDIANA UNIV. 523 GOTOW, K. VPI/STATE UNIV. 567 GRAM, P. A. M. LOS ALAMOS 586 GREENE, S. J. NEW MEXICO STATE UNIV. 512, 572 GREENWOOD, R. C. IDAHO NATIONAL ENGINEERING LAB. 629 HARVEY, A. LOS ALAMOS 326, 406, 560 HARVEY, C. J. UNIV. OF TEXAS, AUSTIN 602 HEFFNER, R. H. LOS ALAMOS 499, 571, 640 HENNING, W. ARGONNE 610 HINTZ, N. M. UNIV. OF MINNESOTA 601, 616, 630 HOEHN, M. V. LOS ALAMOS 494 HOFFMAN, C. M. LOS ALAMOS 400 HOFFMANN, G. W. UNIV. OF TEXAS, AUSTIN 386, 392, 469, 563, 632, 642 HOFSTADTER, R. STANFORD UNIV. 444 HOGAN, J. J. McGILL UNIV. 611 HOISTAD, B. UNIV. OF TEXAS, AUSTIN 405, 456, 485, 533, 535, 649 HOLLAS, C. L. UNIV. OF TEXAS, AUSTIN 636 HUGHES, V. W. YALE UNIV. 421, 464, 529, 552, 646 HYNES, M. V. LOS ALAMOS 561, 643 IGO, G. J. UNIV. OF CALIFORNIA, LOS ANGELES 438, 479, 540, 635, 644 IMAI, K. ARGONNE 512 IROM, F. UNIV. OF CALIFORNIA, LOS ANGELES 633 JARMER, J. J. LOS ALAMOS 517, 518 KAROL, P. J. CARNEGIE-MELLON UNIV. 123, 294 KATZ, R. UNIV. OF NEBRASKA 218 KING, N. S. P. LOS ALAMOS 525 KIZIAH, R. R. UNIV. OF TEXAS, AUSTIN 598 KUTSCHERA, W. ARGONNE 610 LEE, P. L. CALIFORNIA STATE UNIV., NORTHRIDGE 491 LIND, V. G. UTAH STATE UNIV. 439 LING, T. Y. OHIO STATE UNIV. 645 LU, D. C. YALE UNIV. 464, 542 MACLAUGHLIN, D. E. UNIV. OF CALIFORNIA, RIVERSIDE 499, 640 MATIS, H. S. LOS ALAMqS 445 MCCLELLAND, J. B. LOS ALAMOS 616, 630 MCGILL, J. A. RUTGERS UNIV. 469, 626, 642 MICHEL, D. J. NAVAL RESEARCH LAB. 113 MILLER, J. BOSTON UNIV. 648 MINEHART, R. C. UNIV. OF VIRGINIA 567 MOINESTER M. A. LOS ALAMOS/TEL AVIV UNIV. 295, 393, 525 MOORE, C. F. UNIV. OF TEXAS, AUSTIN 572 MORRIS, C. L. LOS ALAMOS 651 MOSS, J. M. LOS ALAMOS 531, 616, 630 MUTCHLER, G. S. RICE UNIV. 336 NEFKENS, B. M. K. UNIV. OF CALIFORNIA, LOS ANGELES 120 NORTHCLIFFE, L. C. TEXAS A&M UNIV. 517, 518, 589, 590 OBENSHAIN, F. E. OAK RIDGE 561 OBRIEN, H. A. LOS ALAMOS 106, 267 ORTH, C. J. LOS ALAMOS 595 PACIOTTI, M. A. LOS ALAMOS 217, 270 PAULETTA, G. UNIV. OF CALIFORNIA, LOS ANGELES 583, 633 PEREZ-MENDEZ, V. LAWRENCE BERKELEY LAB. 215 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory SPOKESMEN INSTITUTIONS EXPERIMENTS PHILLIP!., D. S. UNIV. OF ILLINOIS 407 PHILLIPS, G. C. RICE UNIV. 559 PHILLIPS, T. L. UNIV. OF CALIFORNIA, SAN FRANCISCO 380 PINSKY, L S. UNIV. OF HOUSTON 336 PORILE, N. T. PURDUE UNIV. 349 POSKANZER, A. M. LAWRENCE BERKELEY LAB. 308 PREEDOM, B. M. UNIV. OF SOUTH CAROLINA 576 RAJU, M. R. LOS ALAMOS 236 REIDY, J. J. UNIV. OF MISSISSIPPI 187, 594 RICHMAN, C. LOS ALAMOS 273 RITCHIE, B. G. UNIV. OF SOUTH CAROLINA 567 ROMANOWSKI, T., A. OHIO STATE UNIV. 645 ROOS, P. G. UNIV. OF MARYLAND 576 RUNDBERG, R. S. LOS ALAMOS 466, 500, 553 SCHILLACI, M. E. LOS ALAMOS 571 SCOTT, A. UNIV. OF GEORGIA 356 SEESTROM-MORRIS, S. J. LOS ALAMOS 580 SETH, K. K. NORTHWESTERN UNIV. 405, 508, 533, SHEPARD, J. R. UNIV. OF COLORADO 485 SHERA, E. B. LOS ALAMOS 335 SIMMONS, J. E. LOS ALAMOS 517, 518, 590 SKUBIC, P. UNIV. Or OKLAHOMA 652 SMITH, A. R. UNIV. OF NEW MEXICO 271 SMITH, W. W. UNIV. OF CONNECTICUT 587 SOMMER, W. F. LOS ALAMOS 407 SOUDER, P. A. YALE UNIV. 421 TALAGA, R. L. LOS ALAMOS 634 TALBERT, JR., W. L. LOS ALAMOS 629 TURKEVICH, A. L. UNIV. OF CHICAGO 603 VIEIRA, D. J. LOS ALAMOS 595 WAGNER, R. ARGONNE 498 WHITNEY, R. R. UNIV. OF VIRGINIA 284 WILHELMY, J. B. LOS ALAMOS 544 WU, C. S. COLUMBIA UNIV. 464. 529 YAMAZAKI, Y. HIGH-ENERGY LAB., JAPAN 335 YOKOSAWA, A. ARGONNE 386 YUAN, V. UNIV. OF ILLINOIS 634 ZEIDMAN, B. ARGONNE 480, 565 ZIOCK, K. 0. H. UNIV. OF VIRGINIA 190, 617 July-December 1981 PROGRESS AT LAMPF 145 Los Alamos National Laboratory APPENDIX E VISITORS TO LAMPF DURING THE PERIOD JULY 1 — DECEMBER 31, 1981 Bjarne Aas UC, Los Angeles Douglas Bryman TRIUMF Gary S. Adams Massachusetts Inst, of Tech. William J. Burger Massachusetts Inst, of Tech. Suman K. Agarwal Purdue Univ. George R. Burleson New Mexico State Univ. Richard C. Allen UC, Irvine Steven E. Bush UNM Cancer Center John C. Allred Consultant Jeanne L. Butler UNM Cancer Center Aharon Amittay Yale Univ. Kenneth B. Butterfield Univ. of New Mexico Richard E. Anderson Univ. of North Carolina Michael A. Carchidi Univ. of Pennsylvania Sharon W. Anderson UNM Cancer Center Nicholas S. Chant Univ. of Maryland Barbara L. Anstey UNM Cancer Center Herbert H. Chen UC, Irvine Richard A. Arndt Virginia Poly. Inst./State Univ. Yonghyun Cho Stanford Univ. Mary Jean Arntzen UNM Cancer Center Connel L. Chu M. D. Anderson Hospital Jeffrey E. Arrington Abilene Christian Univ. David A. Clark Univ. of New Mexico Daniel Ashery Tel Aviv Univ. Nance L. Colbert UC, Irvine Nader A. Atari Kuwait Univ. Joseph R. Comfort Arizona State Univ. Alireza Azizi UC, Los Angeles Joseph J. Comuzzi Massachusetts Inst, of Tech. Andreas Badertscher Univ. of Berne David C. Cook Univ. of Minnesota F. Todd Baker Univ. of Georgia William Cottingame New Mexico State Univ. Mike W. Baliard Abilene Christian Univ. Mary L. Courtright UNM Cancer Center Martin L. Barlett Univ. of Texas Donna J. Cremans Univ. of Texas David B. Barlow Northwestern Univ. Gourisankar Das Univ. of Virginia Charles A. Barnes California Inst, of Tech. Sobhendranath Datta UNM Cancer Center Peter D. Barnes Carnegie-Mellon Univ. Kincaid Davidson UNM Cancer Center Bernd Bassalleck Carnegie-Mellon Univ. Glen H. Daw UNM/New Mexico State Univ. Curtis E. Bemis, Jr Oak Ridge Dietrich Dehnhard Univ. of Minnesota Barry L. Berman Lawrence Livermore Lab. Peter P. Denes Univ. of New Mexico Aron Bernstein Massachusetts Inst, of Tech. Arthur B. Denison Univ. of Wyoming William Bertozzi Massachusetts Inst, of Tech. Satish Dhawan Yale Univ. Tarlochan S. Bhatia Texas A&M Univ. Kail ash C. Dhingra Univ. of New Mexico Ewart W. Blackmore TRIUMF Byron D. Dieterle Univ. of New Mexico Leslie C. Bland Univ. of Pennsylvania W. Rodney Ditzler Argonne Gary S. Blanp.'ad Univ. of South Carolina Stanley A. Dodds Rice Univ. Marvin Blecher Virginia Poly. Inst./State Univ. "Peter J. Doe UC, Irvine Elizabeth H. Bleszynski UC, Los Angeles Mohan Doss Univ. of Washington Marek Bleszynski UC, Los Angeles Robert W. Dunn Univ. of New Mexico Carolyn A. Blies UNM Cancer Center Minh V. Duong-Van Rice Univ. Charles L. Blilie Univ. of Minnesota Steven A. Dytman Massachusetts Inst, of Tech. Fred O. Borcherding UC, Los Angeles Thanasis E. Economou Univ. of Chicago Jonathan S. Boswell Univ. of Virginia David A. Edrich UC, Irvine Dale E. Boyce Univ. of Chicago Patrick 0. Egan Yale Univ. Kenneth Boyer Univ. of Texas Andrew D. Eichon UC, Los Angeles James A. Bridge Consultant Robert A. Eisenstein Carnegie-Mellon Univ. William J. Briscoe UC, Los Angeles Richard J. Ellis College of William & Mary Howard C. Bryant Univ. of New Mexico Stephen F. Elston Univ. of Texas 146 PROGRESS AT LAMPF July-December 1931 Los Alamos National Laboratory Peter A. J. Englert UC, San Diego William Haberichter Argonne Adoram Erell Tel Aviv Univ. Isaac Halpern Univ. of Washington Thomas Estle Rice Univ. Ronnie W. Harper Univ. of Illinois John A. Faucett Univ. of Oregon Carol J. Harvey Univ. of Texas Raymond W. Fergerson Univ. of Texas Hiromi Hasai Hiroshima Univ. John M. Finn Massachusetts Inst, of Tech. Rachel Heifetz Tel Aviv Univ. Daniel Fitzgerald UC, Los Angeles Patrick D. Heinz UNM Cancer Center Orris B. Fletcher Argonne Herbert E. Henrikson California Inst, of Tech. H. Terry Fortune Univ. of Pennsylvania John D. Herrmann Purdue Univ. Michael Franey Univ. of Minnesota Virgil L. Highland Temple Univ. Sherman Frankel Univ. of Pennsylvania Robert A. Hilko UNM Cancer Center Gregg B. Franklin Carnegie-Mellon Univ. Daniel A. Hill Argonne William Frati Univ. of Pennsylvania Norton M. Hintz Univ. of Minnesota Hans Frauenfelder Univ. of Illinois Gerald W. Hoffmann Univ. of Texas Gerhard Fricke Univ. of Mainz Kenneth R. Hogstrom M. D. Anderson Hospital W. Jay Friedman Univ. of New Mexico Bo Hoistad Univ. of Texas Charles A. Frost Sandia Labs. Charles L. Hollas Univ. of Texas Hiroshi Fujisawa Univ. of Minnesota Barry R. Holstein Univ. of Massachusetts Francois C. Gaille Temple Univ. James A. Holt UC, Los Angeles Chris J. Gardner Yale Univ. Randy Holt Consultant Richard E. Garland UNM Cancer Center Roy J. Holt Argonne Alain Gauthier Ohio State Univ. David B. Holtkamp Univ. of Minnesota Carol A. Gauthier UNM Cancer Center Irma S. Holtkamp Univ. of Texas David H. Gay Univ. of Minnesota Daniel J. Horen Oak Ridge M. Magdy Gazzaly Univ. of Minnesota E. Barrie Hughes Stanford Univ. Jorge V. Geaga UC, Los Angeles Vernon W. Hughes Yale Univ. Donald F. Geesaman Argonne George J. Igo UC, Los Angeles Robert J. Gehrke EG&G, Idaho, Inc. Hiroshi Ikeda Osaka Univ. Christopher Gilman UNM Cancer Center Kenichi Imai Argonne Ronald A. Gilman Univ. of Pennsylvania Masahiro Itoh ULVAC Corp. Grant A. Gist Rice Univ. Harold E. Jackson Argonne Michael Gladisch Universitat Heidelberg Linwood E. Jackson UNM Cancer Center Charles Glashausser Rutgers Univ. Mark J. Jakobson Univ. of Montana George Glass Texas A&M Univ. Randolph H. Jeppesen Univ. of Montana Timothy W. Glover New Mexico State Univ. Ronald G. Jeppesen Univ. of Montana Alfred S. Goldhaber State Univ. of New York, Wayne A. Johnson UC, Irvine Stony Brook Garth Jones TRIUMF Charles D. Goodman Indiana Univ. Kevin W. Jones Rutgers Univ. Kazuo Gotow Virginia Poly. Inst./State Univ. Richard J. Joseph US Air Force Academy Abigail R. Gould UNM Cancer Center Robin K. Justice UNM Cancer Center Charles A. Goulding EG&G, Los Alamos Laurie D. Kain UNM Cancer Center Michael G. Greene Yale Univ. George R. Kalbfleisch Univ. of Oklahoma Steven J. Greene New Mexico State Univ. Joseph D. Kalen Ohio State Univ. Ghislain S. Gregoire Univ. of Louvain Mark O. Kaletka Consultant Chilton B. Gregory Univ. of New Mexico Jan Kallne Harvard Smithsonian Marvin A. Grimm Univ. of Louisville Elizabeth H. Karpen UNM Cancer Center David P. Grosnick Univ. of Chicago Thomas E. Kasprzyk Argonne Edward E. Gross Oak Ridge Sheldon Kaufman Argonne Ana M. Guevara UNM Cancer Center James J. Kelly Massachusetts Inst, of Tech. Ricardo L. Guevara UNM Cancer Center Charles A. Kelsey UNM Cancer Center July-December 1981 PROGRESS AT LAMPF 147 Los Alamos National Laboratory Robert A. Kenefick Texas A&M Univ. Alfredo Molinari Univ. of Torino Charles R. Key UNM School of Medicine C. Fred Moore Univ. of Texas Mirkutub M. Khan UNM Cancer Center Donald W. Mueller Consultant Mahbubul A. Khandaker Univ. of Washington Bruce Murdock Massachusetts Inst, of Tech. Danuta Kielczewska Northwestern Univ. Sirish K. Nanda Rutgers Univ. Rex R. Kiziah Univ. of Texas Robert A. Naumann Princeton Univ. Donald K. Kohl Consultant B. M. K. Nefkens UC, Los Angeles Jack J. Kraushaar Univ. of Colorado Alvin D. Nelson Univ. of Colorado Raymond Kunselman Univ. of Wyoming Barry J. Nelson Univ. of Texas Dieter Kurath Argonne LeeC. Northcliffe Texas A&M Univ. Deborah A. Landt UNM Cancer Center Vincent J. Novick EG&G, Idaho, Inc. Richard G. Lane UNM Cancer Center Deborah C. 0. Dean UNM Cancer Center Paul L. Lee California Inst, of Tech. Felix E. Obenshain Oak Ridge Patti J. Leistikow UNM Cancer Center Yoshitaka Ohkubo Purdue Univ. Rodger Liljestrand EG&G, Los Alamos Jean M. OBstens Univ. of Oklahoma David A. Lind Univ. of Colorado Yolande A. Oostens Univ. of Oklahoma Earle L. Lomon Massachusetts Inst, of Tech. Lewis J. Orphanos Univ. of Virginia William G. Love Univ. of Georgia Joanne D. Ortega UNM Cancer Center Daniel C. Lu Yale Univ. Estelle C. Osborne UNM Cancer Center Douglas MacLaughlin UC, Riverside PerOsland Harvard Univ. Claudio Magno Virginia Poly. Inst./State Univ. Jeanette M. Palanek UNM Cancer Center Christopher J. Maher Carnegie-Mellon Univ. Alison M. Pannell UNM Cancer Center Hansjuerg Mahler UC, Irvine Jorge Paradelo UNM Cancer Center Charles E. Manger Consultant Gianni Pauletta UC, Los Angeles D. Mark Manley Virginia Poly. Inst./State Univ. Vivekananda Penumetcha Univ. of Georgia John Manley Consultant Richard J. Perez UNM Cancer Center Robert T. Marchini Univ. of New Mexico Roy J. Peterson Univ. of Colorado Fesseha Mariam Yale Univ. Gerald C. Phillips Rice Univ. Jill Ann Marshall Univ. of Texas M. Jolene Phillips UNM Cancer Center Myrna P. Marsteller UNM Cancer Center David J. Pierotti UNM Cancer Center Jo Ann Martinez UNM Cancer Center Philip H. Pile Carnegie-Mellon Univ. Nancy A. Martinez UNM Cancer Center Chandra Pillai Oregon State Univ. Thomas G. Masterson Univ. of Colorado Hans S. Plendl Florida State Univ. Howard S. Matis Consultant Michael A. Plum Univ. of Massachusetts June L. Matthews Massachusetts Inst, of Tech. Norbert T. Porile Purdue Univ. David K. McDaniels Univ. of Oregon Arthur M. Poskanzer Lawrence Berkeley Lab. Arthur B. McDonald Chalk River Nuclear Labs. Richard J. Powers California Inst, of Tech. John A. McGill Rutgers Univ./Univ. of Texas Barry M. Preedom Univ. of South Carolina Robert D. McKeown California Inst, of Tech. Paul E. Prince Abilene Christian Univ. Kok-Heong McNaughton Univ. of Texas/ Brian P. Quinn Massachusetts Inst, of Tech. Case Western Reserve Univ. Ali Rahbar UC, Los Angeles James A. McNeil Univ. of Pennsylvania Mark T. Rakowski Yale Univ. Wido Menhardt Univ. of New Mexico Brenda S. Ramsey UNM Cancer Center Fred A. Mettler UNM Cancer Center Ronald D. Ransome Univ. of Texas/Consultant Ulrich Meyer-Berkhout Univ. of Munich Arthur M. Rask Argonne Gerald A. Miller Univ. of Washington Richard S. Raymond Univ. of Colorado Cas Milner Univ. of Texas Neville W. Reay Ohio State Univ. Ralph C. Minehart Univ. of Virginia Glen A. Rebka Univ. of Wyoming RoryA. Miskimen Massachusetts Inst, of Tech. Robert P. Redwine Massachusetts Inst, of Tech. Alireza Mokhtari UC, Los Angeles Lawrence B. Rees Univ. of Maryland 148 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory Kurt Reibel Ohio State Univ. L. Wayne Swenson Oregon State Univ. James J. Reidy Univ. of Mississippi John J. Szymanski Carnegie-Mellon Univ. Louis P. Remsberg Brookhaven Frank Tabakin Univ. of Pittsburgh James H. Richardson Consultant Fujio Takeutchi Kyoto Sangyo Univ. Ronald J. Rieder Carnegie-Mellon Univ. Henry H. Tamura UNM Cancer Center Peter J. Riley Univ. of Texas Yasutoshi Tanaka Purdue Univ. Robert A. Ristinen Univ. of Colorado Robert L. Tanner Consultant Barry G. Ritchie Univ. of South Carolina Mark W. Tate Abilene Christian Univ. Peggy D. Robertson Michigan State Univ. Daniel R. Tieger Boston Univ. Raymond F. Rodebaugh Univ. of Texas James R. Tinsley Univ. of Oregon Joseph Rolfe Stanford Univ. W. Bradford Tippens Texas A&M Univ. Philip G. Roos Univ. of Maryland Michael J. Tobin Carnegie-Mellon Univ. Isaac I. Rosen UNM Cancer Center Kouichi Toshioka Argonne S. Peter Rosen Purdue Univ. Stephen E. Turpin Rice Univ. Mike A. Rumore Univ. of Colorado Yiharn Tzeng Univ. of Texas Michael E. Sadler Abilene Christian Univ. John L. Ullmann Univ. of Colorado Arunava Saha Northwestern Univ. David G. Underwood Argonne Richard T. Scalettar UC, Irvine Jeffrey E. Ungar California Inst, of Tech. Stefan J. A. Schmitz UC, Los Angeles Albert Van der Kogel UNM Cancer Center Alan Scott Univ. of Georgia Clara G. Villareal UNM Cancer Center Ralph E. Segel Northwestern Univ. Robert A. Visel UNM Cancer Center Peter A. Seidi Univ. of Texas John B. Wagner UC, Los Angeles Robert Serber Columbia Univ., New York Robert G. Wagner Argonne Kamal K. Seth Northwestern Univ. John D. Walecka Stanford Univ. Stephen L. Shaffer Abilene Christian Univ. Gloria S. Walker UNM Cancer Center James R. Shepard Univ. of Colorado Thad G. Walker Abilene Christian Univ. Gary M.Sherman UNM Cancer Center Stephen J. Wallace Univ. of Maryland Seiichi Shibata Carnegie-Mellon Univ. Angel T. M. Wang UC, Los Angeles Frank T. Shively Lawrence Berkeley Lab. Keh-Chung Wang UC, Irvine Edward R. Siciliano Univ. of Colorado John E. Warren Lakehead Univ. Ronald A. Sidwell Fermi National Accel. Lab. Mial E. Warren Rice Univ. Philip J. Siemens Texas A&M Univ. GaryS. Weston UC, Los Angeles Margaret L. Silbar Consultant William R. Wharton Carnegie-Mellon Univ. Terrence P. Sjoreen Oak Ridge John A. White Univ. of Oklahoma Patrick L. Skubic Univ. of Oklahoma Morris L. Whiten Armstrong State College Roy T. Slice UNM Cancer Center R. Roy Whitney Univ. of Virginia Alfred R. Smith UNM Cancer Center Charles A. Whitten UC, Los Angeles Chester R. Smith Consultant Jay A. Wightman UC, Los Angeles Christopher W. Smith UNM Cancer Center Gary R. Wilkin Carnegie-Mellon Univ. David E. Smith Northwestern Univ. Robert Wilson Columbia Univ., New York Nancy J. Smith UNM Cancer Center Stephany Wilson UNM Cancer Center steven L. James R. Specht Argonne Wilson Stanford Univ. Harold M. Spinka Argonne David Wolfe Univ. of New Mexico Patrick M. Stafford UNM Cancer Center Stephen A. Wood Massachusetts Inst, of Tech. Robert W. Stanek Argonne S. Courtenay Wright Univ. of Chicago Richard H. Stark UNM Cancer Center Ming-Jen Yang Univ. of Chicago Rolf M. Steffen Purdue Univ. Joseph Yellln Jet Propulsion Lab. Robert T. Stein Rice Univ. Akihiko Yokosawa Argonne Kenneth E. Stephenson Argonne Vincent Yuan Univ. of Illinois Derek W. Storm Univ. of Washington Benjamin Zeidman Argonne Juty-DBcember 1981 PROQRESSATLAMPF 149 Los Alamos National Laboratory Steve A. Zellpsky Argonne Gisbertzu Putlitz Universitat Heidelberg J. Floyd Zimmerman Consultant John D. Zumbro Princeton Univ. Sandra R. Zink UNM CancerCenter Paul Zupranski Northwestern Univ. Klaus 0. H. Ziock Univ. of Virginia 150 PROGRESS AT LAMPP July-December 1981 Los Alamos National Laboratory INFORMATION FOR CONTRIBUTORS Progress at LAMPF is the progress report of MP Division of Los Alamos National Laboratory. In addition it includes brief reports on research done at LAMPF by researchers from other institutions and Los Alamos National Laboratory divisions. Progress at LAMPF is published semiannually on April 1 and October 1. This schedule requires that manuscripts be received by December 1 and June 1, respectively. Published material is edited to the standards of the Style Manual of the American Institute of Physics. Papers are not refereed, hence presentation in this report does not constitute professional publication of the material nor does it preempt publication in other journals. Contributors can expedite the publication process by giving special care to the following specifics: 1. Drawings and Figures submitted should be of quality suitable for direct reproduction after reduc tion to single-column width, 83 cm (3-1/4 in.). 2. Figure captions and table headings should be furnished. 3. References should be complete and accurate. 4. Abbreviations and acronyms should be avoided if possible (in figures and tables as well as text), and when used must be defined. 5. All numerical data should be given in SI units. 6. Authors are reminded that it helps the reader to have an introduction, which states the purpose(s) of the experiment, before presentation of the data. Research reports should be brief, one printed page or less, including figures (approximately three double- spaced typed pages). A list of recent publications relating to the experiment, for separate tabulation in this report, is much appreciated. Contributors are encouraged to include as authors all participants in experiments so that they may receive credit for authorship and participation. Questions and suggestions should be directed to John C. Allred, Los Alamos National Laboratory, MS 850, Los Alamos, NM 87545. July-December 1981 PROGRESS AT LAMPF 151 Los Alamos National Laboratory ERRATUM In the Los Alamos National Laboratory report LA-8994-PR, Progress at LAMPF, January-June 1981, on p. 38, the spokesmen for Exp. 225 were incorrectly given. The spokesman for this experiment is H. H. Chen (University of California at Irvine). 152 PROGRESS AT LAMPF July-December 1981 Los Alamos National Laboratory &U.5. GOVERNMENT PRINTING OFFICE: 1982-0-576-0 20/3!