V aaAoo i^ni-joyoiiA! joMor] SLAC USERS BULLETIN NO. 96 August - December 1983 CONTENTS Page 1. Experimental Ac t iv it y 3 2 . PEP Activities 6 3. SPEAR Activities 6 4. Data Analysis Group Ac t iv it y 7 5. EPAC Ac t io n s 8 6. SEC Activities 9 7. NPAS - Nuclear Physics atSLAC 10 8. Current Tentative Long Range Schedule 13 9. Table of Approved Experiments 14 10. Accelerator and Research Operations 19 Notices Next EPAC Meeting May 4.5. 1984 Next SPC Meeting June 8.9. 1984 II DlSTRini!TiGi< o r THiS mIS W M DO NOT MICROFILM COVER SLAC's Scientific Policy Cornmittee The interests of SLAC's User community are represented by the SLAC Scientific Policy Committee, which meets several times a year to review SLAC's program and policies, its relationship with Users, and the like. Users and prospective Users of the SLAC facility are invited to address any problems or suggestions they may have to any of the members of the SPC. The present membership of the SPC is given below. Term expires June 30, 1984 E. Goldwasser (Chairman) U. Illinois D. Jackson LBL-UCB J. Bjorken Fermilab U. Nauenberg U. Colorado C.-y. Chien John Hopkins U. R. Prepost U. Wisconsin B. Gittelman Cornell U. Term expires June 30, 1986 C. Baltay Columbia U. E. Picasso CERN C . Buchanan UCLA P . Reardon Princeton U. C. Callan Princeton U. A . Stewart-Smith Princeton U. D . Nygren LBL-UCB H. Ticho UCLA SLAC's Experimental Program Advisory Committee The Experimental Program Advisory Committee (EPAC) consists of twelve members and ad­ vises the Director of SLAC in establishing the program commitments for the accelerator and experimental facilities. Meetings are scheduled as often as necessary, but no less than twice a year. All new proposals submitted to the EPAC two months before a given EPAC meeting will be considered at that meeting. Proposals for experiments at SLAC should be sent to the EPAC Secretary, David Fryberger, SLAC, Bin 20. For details of proposal preparation and submittal, please refer to the SLAC Users Handbook. Term Expires 1984 Karl Berkelman Cornell University Gerald Smith Pennsylvania State Univ. William Carithers Lawrence Berkeley Lab Richard Taylor SLAC Michel Davier Orsay Albert Wattenberg University of Illinois Paul Grannis SUNY-Stony Brook Sau Lan Wu U. Wisconsin and DESY Helen Quinn SLAC Term Expires 1985 Robert Jaffe M.I.T. Melv5m Shochet University of Chicago Robert Sugar U.C.-Santa Barbara Gunther Wolf DESY SLAC USERS BULLETIN (C/0 EFD, Bin 20) Stanford Linear Accelerator Center* Stanford University - Stanford, California - 94305 Editors: Lewis P. Keller - Dorothy Edminster *Operated by Stanford University under contract with the U. S. Department of Energy SLAC USERS BULLETIN NO. 96 Au g u s t - D e c e m b e r 1983 CONTENTS Pag e 1. Experimental Ac t i v i t y 3 2. PEP Ac t i v i t i e s 6 3. SPEAR A c t i v i t i e s 6 4. D a t a An a l y s i s Gr o u p Ac t i v i t y 7 5. EPAC Ac t i o n s 8 6. SEC Ac t i v i t i e s 9 7. NPAS - N u c l e a r Ph y s i c s a t SLAC 10 8. Cu r r e n t Te n t a t i v e Long Ra n g e S c h e d u l e 13 9. Ta b l e o f Ap p r o v e d Ex p e r i m e n t s 14 10. Ac c e l e r a t o r a n d Re s e a r c h Op e r a t i o n s 19 N o t i c e s N e x t EPAC Me e t i n g Ma y 4.5. 1984 N e x t SPC Me e t i n g J une 8.9. 1984 SLAC— 96 DE84 008182 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use­ fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any spe­ cific commercial product, process, or service by trade name, trademark, manufac­ turer, or otherwise does not necessarily constitute or imply its endorsement, recom­ mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. POflTiOfiS ---- possible availability. 1. EXPERIMENTAL ACTIVITY A. General energy was changed from 20 GeV to 10 GeV for BC-76 (Threshold Enhancement in Associated Follcwlng a three-month sunmer shutdown in Cliarm Meson-Charmed Baryon Production). A the experimental area the accelerator quick scan of the 10 GeV run was completed operated in the SLED mode at 60 pps for most by mid-December and turned up no charmed of Octdber through December. In the PEP lambda events, so data-taking for that ring two projects v\hich were hoped to bring experiment is concluded. high luminosity and more reliable operation were completed in September: (1) The entire In Ehd Station B, channeling experiment D-30 ring v\a.s realigned, and (2) the twa families ran in the positron beam, sharing the cycle of sextupole magnets were powered with several other tests. The hadron test independently, which may allow lower beta at beam was also active for SLD detector the IP' s. After the shutdown PEP had development work. (L. Keller) difficulty storing a beam, and when stable operation was finally achieved, the B. Program Status and Reports of luminosity was approxiii\ately half that of Experiments and Tests the previous cycle. The realignment did not help a bit, in fact it made things worse 1 Figure 1 is a research area plan showing the From experience it was felt that with location of experiments and facilities. continued tweaking by the operators, the Figure 2 shows locations of the experimental luminosity would gradually improve; so PEP beam lines in the research area. Figure 3 continued to operate uninterrupted for shows the Long-Range Schedule. Table I is a experiments through most of Decan±ier. Both list of presently approved high energy HRS and TPC suffered setbacks. HRS had experiments. The right hand column of Ihble refrigerator problems vhich forced a I gives the status and activity of each decision to warm up the coil. The cooldown experiment during the cycle. went much better than expected and the experiment was back on-line by early Deceamber. TPC iiad difficulty with the superconducting coil supports and will not be able to start testing the magnet again BC-75 - Charm Photoproduction at 20 GeV - until about April 1984. They are (G. Kahnus, Rutherford Lab., and K. Moffeit, expected to be back onto the PEP beam line S L ^ in September 1984. Ihey are also using this time to make several modifications to BC-75 finished data taMng Decenber 22 with the TPC and to repair two of the six barrel 645,000 pictures obtained between Octcber calorimeter modules. Ttie TPC problem also and December 1983. Work is in progress on keeps IWo-Gartria off. When the accelerator the analysis of this data and that taken in turned off on 23 Decaitoer for a scheduled the spring. A collaboration workshop was ten-day shutdown PEP had accumulated about held at SLAC December 12-16 to scrutinize 23 inverse picobarns. During the short new charm event candidates. (K. Moffeit) shutdown a new vacuum pipe and masking and several detector conponents were installed BC-76 Threshold Enhancement in Charm in IR-10 for PEP-21 (Anomalous Photon Photoproduction - Univ. Birmingham, Search). In IR-2 a new nine-meter mask was Imperial College (London), Rutherford labTT* installed for Two-Gamma to test a BGO U.C. Berkeley, Univ. of Tennessee, SLAC, detector for tagging very small angle (4-10 MIT - (B. Franek, Univ. Birmingham, J. mrad) electron positron scattering. Brau, Univ. Tennessee) SPEAR also had trouble storing a beam following the summer shutdown and could not A proposal to exploit a threshold reproduce the luminosity attained in erihancament in charm photoproduction (BC-76) previous cycles for MARK III. In Novesmber at the SLAC Hybrid Facility was approved by and Decarber SPEAR switched to single beam the EPAC on November 1, contingent upon a operation for SSRL. demonstration that the enhancement exists. To test the theoretical prediction of the In End Station C Experiment BC-75 (Chanm enhancement, the photon beam serving the Study in the SLAC Hybrid Facility) ran in SLAC Hybrid Facility \«s converted from its October and early NOvamber in the normal 20 GeV operation to 10.5 GeV on backscattered laser beam. During the last Noveiber 4. This low energy beam was three weeks of November the fhoton beam established by running the laser with - 3 - DISTRIBUTION OF THIS DOCUMENT IS UNLIMITE5 frequency doubled (rather than quadrupled) Throughout the fall cycle the detector, photons and running the linac at 23.3 GeV. operated reliably and by the middle of The ccmponent changes required for this December, 16 pb~l of luminosity had been switch-over were acccnplished in a few hours recorded.