DOCSLIB.ORG

January 2008 (Volume 17, Number 1) Entire Issue

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

January 2008 Volume 17, No. 1 www.aps.org/publications/apsnews APS NEWS Meet the New APS President A PublicAtion of the AmericAn PhysicAl society • www.APs.org/PublicAtions/APsnews Page 3 APS April Meeting Convenes in St. Louis APS Launches New Prize for Approximately 1200 physicists In keeping with the more gener- the APS Committee on Minorities are expected to attend the 2008 APS alist tone of the April Meeting, ten in Physics (COM) and Committee Industrial Applications of Physics April Meeting, to be held April 12- exciting plenary talks will highlight on the Status of Women in Physics APS is calling for nominations and thereby to publicize the value 15 in St. Louis, Missouri. The scien- the technical program. (CSWP), and a special symposium for its new Industrial Applications of physics in industry, to encour- tific program, which focuses on as- Numerous special events are also celebrating the 50-year history of of Physics Prize. The Prize was age physics research in industry, trophysics, particle physics, nuclear planned for the April Meeting, in- Physical Review Letters. approved by Council last spring, and to enhance students’ aware- physics, gravitation and cosmol- The Division of Particles and and will be awarded for the first ness of and interest in the role of ogy, will consist of three ple- Fields has scheduled several time at the 2009 March Meeting. physics in commercial product nary sessions, approximately 72 special invited sessions and is The selection process for the first development.” invited sessions, more than 100 planning evening sessions on Prize will take place in the spring John Jaros, 2007 Chair of the contributed sessions, and poster the theme “A New Era in US and summer of 2008. APS Prizes and Awards Commit- sessions. This year the meeting Particle Physics.” April Meet- According to the description of tee, said “This Prize is designed to will be held in conjunction with ing program chair Natalie Roe the Prize, it is “awarded to an in- attract not only physicists in larger a conference sponsored by HEDP pointed out that in the next few dividual, or individuals, for appli- companies, but also the increasing (High Energy Density Physics) years, accelerators in the US cations of physics in an industrial number of industrial physicists and HEDLA (High Energy Den- will be shutting down, the Large setting. The purpose of the prize working in small companies and sity Laboratory Astrophysics). Hadron Collider will be turning is to recognize excellence in the start-ups. The emphasis will be on APS units represented at the on, and planning is underway for industrial application of physics, PRIZE continued on page 7 meeting include the Divisions the International Linear Collider. of Astrophysics, Nuclear Phys- “It’s a time of transition in par- Token of Appreciation ics, Particles and Fields, Physics ticle physics,” she said. of Beams, Plasma Physics, and The abstract submission dead- Computational Physics; the Fo- line is January 11; post-deadline rums on Education, Physics and abstracts received by February Society, International Affairs, His- cluding a high school physics teach- 8 will be assigned as poster presen- tory of Physics, and Graduate Stu- ers’ day, a student career panel and tations on a space-available basis. dent Affairs; and the Topical Groups networking reception, a students Early registration closes on Febru- on Few-Body Systems, Precision lunch with the experts, a “meet the ary 22. Measurement and Fundamental APS journal editors” reception, More information about the Constants, Gravitation, Plasma As- the presentation of APS prizes and April Meeting: http://www.aps.org/ trophysics, and Hadronic Physics. awards, a reception sponsored by meetings/april/index.cfm Turning 50, PRL Plans a Banner Year This year, Physical Review still the best. The 50th anniver- Gene Sprouse. Letters celebrates its 50th anni- sary is a great time to look back A number of activities are versary. Special events as well at the outstanding physics we've planned for PRL’s golden an- as special features in the journal published in PRL, but also an niversary year, including spe- and online are planned. opportunity for us to introduce cial sessions and receptions at PRL was first published in the March and April Meetings, July 1958 when Editor Sam a symposium and banquet on Photo by Ken cole Goudsmit started the journal as Long Island in June, and spe- A new tradition was inaugurated at the APS Council meeting in November, an experiment. It took the brief cial events at several meetings when executive officer Judy franz (right) presented past-President John hopfield with a bound volume of the minutes of theb oard and council meet- contributions that would have around the world. ings that he chaired in 2006, as a token of appreciation for all the services been published as letters to the These sessions will include that he rendered to the society during his Presidential term. editor in Physical Review, and talks on the history and future of collected them in a separate the APS journals, as well as talks Council Calls for Reduced Greenhouse Gas Emissions journal in order to make impor- about the history of the physics At its November meeting, APS mitigating actions are taken, signifi- tant results available quickly. some exciting new improve- that has been published in the Council passed a statement on global cant disruptions in the Earth’s physi- “Physical Review Letters was ments on which we are work- journals. At the March Meet- warming that calls for immediate ac- cal and ecological systems, social the first letters journal, and it is ing,” said APS Editor-in-Chief PRL continued on page 3 tion to reduce greenhouse gas emis- systems, security and human health sions. The statement also calls for are likely to occur. We must reduce Panel Hears Pros and Cons Of Open-Access Publishing more research to better understand emissions of greenhouse gases be- By Calla Cofield the effects of human activity on the ginning now. Open Access publishing was one org ), but papers posted there are not of loss were to occur in the 25 times climate. The complete text of the Because the complexity of the topic of intense discussion at the No- peer-reviewed. The purpose of Open larger journal, Physical Review D, it statement follows. climate makes accurate prediction vember meeting of the High Energy Access, said Mele, is to “grant any- would not be sustainable. APS offers Emissions of greenhouse gases difficult, the APS urges an enhanced Physics Advisory Panel (HEPAP), body, anywhere, at anytime access to another form of Open Access in the from human activities are chang- effort to understand the effects of hu- whose members advise the federal peer reviewed, publicly funded HEP journals Physical Review A-E, Physi- ing the atmosphere in ways that af- man activity on the Earth’s climate, government on the national program research.” cal Review Letters, and Reviews of fect the Earth’s climate. Greenhouse and to provide the technological op- in high energy physics (HEP). APS At the HEPAP meeting, Sprouse Modern Physics. Anyone can pay a gases include carbon dioxide as well tions for meeting the climate chal- Editor-in-Chief Gene Sprouse ad- said that he supports the principle of fee to make the article free for all to as methane, nitrous oxide and other lenge in the near and longer terms. dressed the general subject of Open Open Access, but there needs to be a read on the APS website. However, gases. They are emitted from fossil The APS also urges governments, Access and its relation to APS, and financially sustainable model. only 30 out of about 18,000 papers fuel combustion and a range of in- universities, national laboratories Salvatore Mele of CERN described Open Access programs have been have been purchased since the pro- dustrial and agricultural processes. and its membership to support poli- SCOAP3, an Open Access model available in different forms for years, gram started a year and a half ago. The evidence is incontrovertible: cies and actions that will reduce the that is gaining steam in the European and are already the basis of some The European Physical Journal Global warming is occurring. If no emission of greenhouse gases. particle physics community. physics journals. One APS journal, has a similar program online. In No- Open Access initiatives began Physical Review Special Topics–Ac- vember 2007, EPJ made its Europe- Printing problem for APS News? in the biological sciences commu- celerators and Beams, is an online- an Physical Journal C–Particles and we have received complaints from some readers that their cop- nity, and have been attracting inter- only Open Access journal, funded by Fields open access, to experimental ies of the December issue were unreadable. we are asking any- est in high energy physics. The high a consortium of large labs. PR-STAB papers only, without cost to the au- one who had this problem to let us know by sending a message to energy physics community has for is not quite recovering its costs, said thor, although it is still maintaining [email protected]. if you wish, you can request a replacement years been making preprints freely Sprouse. In effect APS helps to spon- its regular subscription rates. copy in the message and we'll be happy to send one to you. accessible on the arXiv (http://arxiv. sor this journal, but if the same level PANEL continued on page 6 2 • January 2008 APS NEWS Members in the Media This Month in Physics History “Physicists love to nitpick, so for on the ground.” Edwin Hubble expands our view of the universe the 100 in the 10 million people who Wendy Freedman, Carnegie Insti- might watch the show, I try to get it as tution, on next generation telescopes, ntil the mid 1920s, most scientists thought the redshifted, indicating that most of the nebulae were re- close to 100% accurate as I can.
Recommended publications
  • Information to Users

    Information to Users

    INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 313/761-4700 800/521-0600 Order Number 9S16211 Laser diagnostics of atomic hydrogen and oxygen production in RF and microwave plasma discharges Preppemau, Bryan Lee, Ph.D. The Ohio State University, 1993 UMI 300 N.
  • 2005 CERN–CLAF School of High-Energy Physics

    2005 CERN–CLAF School of High-Energy Physics

    CERN–2006–015 19 December 2006 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 2005 CERN–CLAF School of High-Energy Physics Malargüe, Argentina 27 February–12 March 2005 Proceedings Editors: N. Ellis M.T. Dova GENEVA 2006 CERN–290 copies printed–December 2006 Abstract The CERN–CLAF School of High-Energy Physics is intended to give young physicists an introduction to the theoretical aspects of recent advances in elementary particle physics. These proceedings contain lectures on field theory and the Standard Model, quantum chromodynamics, CP violation and flavour physics, as well as reports on cosmic rays, the Pierre Auger Project, instrumentation, and trigger and data-acquisition systems. iii Preface The third in the new series of Latin American Schools of High-Energy Physics took place in Malargüe, lo- cated in the south-east of the Province of Mendoza in Argentina, from 27 February to 12 March 2005. It was organized jointly by CERN and CLAF (Centro Latino Americano de Física), and with the strong support of CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas). Fifty-four students coming from eleven different countries attended the School. While most of the students stayed in Hotel Rio Grande, a few students and the Staff stayed at Microtel situated close by. However, all the participants ate their meals to- gether at Hotel Rio Grande. According to the tradition of the School the students shared twin rooms mixing nationalities and in particular Europeans together with Latin Americans. María Teresa Dova from La Plata University was the local director for the School.
  • Real Time Density Functional Simulations of Quantum Scale

    Real Time Density Functional Simulations of Quantum Scale

    Real Time Density Functional Simulations of Quantum Scale Conductance by Jeremy Scott Evans B.A., Franklin & Marshall College (2003) Submitted to the Department of Chemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2009 c Massachusetts Institute of Technology 2009. All rights reserved. Author............................................... ............... Department of Chemistry February 2, 2009 Certified by........................................... ............... Troy Van Voorhis Associate Professor of Chemistry Thesis Supervisor Accepted by........................................... .............. Robert W. Field Chairman, Department Committee on Graduate Theses This doctoral thesis has been examined by a Committee of the Depart- ment of Chemistry as follows: Professor Robert J. Silbey.............................. ............. Chairman, Thesis Committee Class of 1942 Professor of Chemistry Professor Troy Van Voorhis............................... ........... Thesis Supervisor Associate Professor of Chemistry Professor Jianshu Cao................................. .............. Member, Thesis Committee Associate Professor of Chemistry 2 Real Time Density Functional Simulations of Quantum Scale Conductance by Jeremy Scott Evans Submitted to the Department of Chemistry on February 2, 2009, in partial fulfillment of the requirements for the degree of Doctor of Philosophy Abstract We study electronic conductance through single molecules by subjecting
  • The Struggle for Quantum Theory 47 5.1Aliensignals

    The Struggle for Quantum Theory 47 5.1Aliensignals

    Fundamental Forces of Nature The Story of Gauge Fields This page intentionally left blank Fundamental Forces of Nature The Story of Gauge Fields Kerson Huang Massachusetts Institute of Technology, USA World Scientific N E W J E R S E Y • L O N D O N • S I N G A P O R E • B E I J I N G • S H A N G H A I • H O N G K O N G • TA I P E I • C H E N N A I Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. FUNDAMENTAL FORCES OF NATURE The Story of Gauge Fields Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN-13 978-981-270-644-7 ISBN-10 981-270-644-5 ISBN-13 978-981-270-645-4 (pbk) ISBN-10 981-270-645-3 (pbk) Printed in Singapore.
  • January 2007 Volume 16, No

    January 2007 Volume 16, No

    January 2007 Volume 16, No. 1 APS NEWS www.aps.org/publications/apsnews Highlights Wireless Non-Radiative Energy Transfer A PUBLICATION OF THE AMERICAN PHYSICAL SOCIETY • WWW.APS.ORG/PUBLICATIONS/APSNEWS Page 6 Particle Physicists Meet Halfway Jacksonville Hosts 2007 April Meeting The 2007 APS April Meeting will cists, a high school teachers’ day, a and registration information, be held April 14-17 in sunny students lunch with the experts, and are available online at Jacksonville, Florida. The scientific the presentation of several APS prizes http://www.aps.org/meetings/april/ program, which focuses on astro- and awards in a special ceremonial index.cfm. The abstract submission physics, particle physics, nuclear session. A public lecture, on the deadline is January 12; post-dead- physics, and related fields, will con- physics of NASCAR, will be given line abstracts received by February 5 sist of three plenary sessions, approx- by Diandra Leslie-Pelecky of the will be assigned as poster presenta- imately 75 invited sessions, more University of Nebraska. tions. Early registration closes on than 100 contributed sessions, and Further details of the program, February 23. poster sessions. Among the invited sessions will April Meeting Plenary Talks be a special Nobel Prize session at Saturday, April 14 Laboratory which both of this year’s laureates, • String Theory, Branes, and if John Mather and George Smoot, will • First Results from Gravity You Wish, the Anthropic speak. Probe B, Francis Everitt, Stanford University Principle, Shamit Kachru, APS units represented at the meet- Stanford University ing include the Divisions of • Two-Dimensional Electron Photo by Kay Kinoshita Astrophysics, Nuclear Physics, Systems, Allan MacDonald, Tuesday, April 17 Particles and Fields, Physics of University of Texas at Austin • The 21-cm Background: A The APS Division of Particles and Fields held a joint meeting with their colleagues Beams, Plasma Physics, and • New Measurement of the Probe of Reionization and the from the Japanese Physical Society in Honolulu.
  • Leo P. Kadanoff (1937–2015): an Appreciation RETROSPECTIVE

    Leo P. Kadanoff (1937–2015): an Appreciation RETROSPECTIVE

    RETROSPECTIVE Leo P. Kadanoff (1937–2015): An appreciation RETROSPECTIVE Susan N. Coppersmitha,1 Leo P. Kadanoff, who died on October 26, 2015, models depended greatly on devoted his scientific life to trying to elucidate how small changes in the ingre- much of the world can be understood using mathe- dients put into the models. matical models. Historically, physics has addressed this Leo recognized that this sen- problem by searching for fundamental laws that com- sitivity of the results on the pletely specify the right ingredients to put into a theo- details of the models that he retical model. For example, the standard model of constructed made it difficult to particle physics provides a specification of the proper- make robust predictions, and ties of elementary particles and their interactions. after several years he returned Inprinciple,thestandardmodelcouldbeusedto to physics research (6). Over describe macroscopic physical systems. However, the succeeding decades, Leo because of the enormous number of elementary investigated a broad variety of particles in any macroscopic amount of matter, imple- complex systems, with a particu- menting such a calculation is not feasible. Leo was the lar focus on identifying phenom- first to understand clearly that the behavior of systems ena with universal features. He on different length scales can be understood using excelled at bringing people to- different effective theories, and that the effective gether to perform interdisciplin- theories that describe macroscopic phenomena should ary investigations incorporating be derivable by a suitable mathematical procedure theory, experiment, and compu- from the microscopics (1, 2). K. G. Wilson succeeded in tation, and thought deeply about constructing a complete mathematical formulation of the role of computation in scien- Leo P.
  • Nehmen Wir An, Die Kuh Ist Eine Kugel... «

    Nehmen Wir An, Die Kuh Ist Eine Kugel... «

    dtv Lawrence M. Krauss »Nehmen wir an, die Kuh ist eine Kugel ...« Nur keine Angst Vor Physik Nicht nur Faust wollte wissen, »was die Welt im Innersten zusammenhält.« Dabei muß man kein Physiker sein, um das moderne Weltbild der Physik – von Galilei Bis Stephen Hawking – zu verstehen. Lawrence M. Krauss zeigt uns, wie spannend und unterhaltsam die Beschäftigung mit der Physik sein kann. Deutscher Taschenbuch Verlag »Nehmen wir an, die Kuh ist eine Kugel...« Ziemlich abwegig, mag mancher denken. Aber wie sinnvoll solche radikalen Ver- einfachungen sein können, zeigt Lawrence M. Krauss an vielen anschaulichen und vergnüglichen Beispielen. Wer wissen will, »was die Welt im Innersten zusammenhält«, sieht nach der Lektüre dieses Buches klarer, denn man muß kein Physiker sein, um das moderne Weltbild der Physik - von Galilei bis Stephen Hawking - zu verstehen. «Mit der Selbstverständlichkeit eines Hausherrn führt Krauss seine Leser durch das Gedankengebäude der theoretischen Physik: von der Relativitätstheorie über die Quantendynamik hin zu einer Theorie >über alles<. Weil er dabei so originell und unkonventionell vorgeht wie sein Lehrer Richard Feynman, ist die Lektüre das reine Vergnügen.« (Physikalische Blätter, Weinheim) Lawrence M. Krauss, geboren 1954 in New York, ist Professor für Physik und Astronomie und Leiter des Instituts für Physik an der Case Western Reserve University in Cleveland. Er lieferte bedeutende Beiträge über die Vorgänge bei explodierenden Sternen bis hin zum Ursprung und der Natur des Stoffes, aus dem das Universum ist. Zahlreiche Veröffentlichungen. Lawrence M. Krauss »Nehmen wir an, die Kuh ist eine Kugel... « Nur keine Angst vor Physik Mit 39 Schwarzweißabbildungen Aus dem Amerikanischen von Wolfram Knapp Deutscher Taschenbuch Verlag Ungekürzte Ausgabe August 1998 Deutscher Taschenbuch Verlag GmbH & Co.
  • Primary Study of High-Power Graphene Beam Window

    Primary Study of High-Power Graphene Beam Window

    Haijing Wang IHEP, Beijing, China 30th, April, 2018, IPAC18, Vancouver Backgrounds Primary studies of high power graphene beam window Vacuum performance Thermal performance Anti-pressure ability Scattering effect Radiation lifetime Summary 2 What is high-power beam window? Used to separate high vacuum region from other atmospheres. Key device for high-power hadron beam accelerators. Beam passes through the window to impinge the target or beam dump. Beam dump window Proton beam window Beam dump window 3 Proton beam windows of some accelerators Side cooling (forced water) • CSNS (0.1 MW): A5083-O Surface cooling (forced water) • SNS (1MW): Inconel 718 • J-PARC (1MW): A5083-O • ISIS (0.16MW): Inconel 718 Multi-pipe cooling (forced water) Side cooling Surface cooling • ESS (5MW): A6061-T6 Different structure (cooling), similar materials (metal) Multi-pipe cooling 4 High power high intensity (hadron) accelerators are more and more needed for different fields of science. Spallation neutron source (eg. ESS 5MW, 2.5 GeV ) Accelerator-driven system (eg. CADS ~10 MW, 1GeV ) Neutrino facility (eg. MOMENT 15 MW, 1.5 GeV) High intensity leads to high energy deposition. High power beam windows meet bottlenecks in heat dissipation and thermal stress. Beam window in study Plasma window: in experimental stage 5 Requirements Vacuum Gas impermeability Pressure difference High thermal conductivity Vacuum Pressure Energy Enough strength side side deposition Beam Optimized structure and Thermal cooling methods pulse Low-Z material Scattering effect Thin film High power & Radiation Radiation resistant high intensity 6 Common-used Inconel GlidCop Al- A6061-T6 Beryllium materials 718 15 Thermal conductivity 167 14.7 216 365 (W/(m·C)) Questions Thermal conduction problem Graphitized Diamond Graphene Not-used materials polyimide Graphene film film film (GPI) Thermal conductivity Up to 900- Up to 4840- Up to 1750 Up to 1940 (W/(m·C)) 2320 5300 Low Questions Brittle Very thin strength Why Graphene? Low-Z.
  • Chicago Physics One

    Chicago Physics One

    CHICAGO PHYSICS ONE 3:25 P.M. December 02, 1942 “All of us... knew that with the advent of the chain reaction, the world would never be the same again.” former UChicago physicist Samuel K. Allison Physics at the University of Chicago has a remarkable history. From Albert Michelson, appointed by our first president William Rainey Harper as the founding head of the physics department and subsequently the first American to win a Nobel Prize in the sciences, through the mid-20th century work led by Enrico Fermi, and onto the extraordinary work being done in the department today, the department has been a constant source of imagination, discovery, and scientific transformation. In both its research and its education at all levels, the Department of Physics instantiates the highest aspirations and values of the University of Chicago. Robert J. Zimmer President, University of Chicago Welcome to the inaugural issue of Chicago Physics! We are proud to present the first issue of Chicago Physics – an annual newsletter that we hope will keep you connected with the Department of Physics at the University of Chicago. This newsletter will introduce to you some of our students, postdocs and staff as well as new members of our faculty. We will share with you good news about successes and recognition and also convey the sad news about the passing of members of our community. You will learn about the ongoing research activities in the Department and about events that took place in the previous year. We hope that you will become involved in the upcoming events that will be announced.
  • CHICAGO PHYSICS 3 Quantum Worlds

    CHICAGO PHYSICS 3 Quantum Worlds

    CHICAGO PHYSICS 3 Quantum Worlds Welcome to the third issue of Chicago Physics! This past year has been an eventful one for our Department and we hope that you will join in our excitement. In our last issue, we highlighted our Strickland from University of Waterloo, the Department’s research on topological physics, third Maria Goeppert-Mayer Lecturer and the covering the breadth of what we do in this third female Physics Nobel Prize winner. research area from the nano to the cosmic The University has renamed the Physics scale and the unity in the concepts that drive Research Center that opened in 2018 as the us all. In the current issue, we will take you on Michelson Center for Physics in honor of a journey to the quantum world. former faculty member Albert A. Michelson, The year had several notable events. The a pioneering scientist who was the first physics faculty had a first-ever two-day retreat American to win a Nobel Prize in the sciences, in New Buffalo, MI. We discussed various and the first Physics Department chair at challenges in our department in a leisurely, the University of Chicago. The pioneering low-pressure atmosphere that allowed us work of Michelson is fundamental to the field to make progress on these challenges. This of physics and continues to support new retreat also helped us to bond!! We were discoveries more than a century later. pleased that many family members joined This year we also welcomed back our own lunch and dinner. This was immediately David Saltzberg (Ph.D., 1994) as the followed by a two-day retreat of our women annual Zachariasen lecturer who told of his and gender minority students.
  • Mael Flament, E-Beam Welding & Machining

    Mael Flament, E-Beam Welding & Machining

    e- BEAM WELDING & MACHINING Mael Flament (MSI) Stony Brook University Dept. of Physics & Astronomy PHY 554, Dec. 2016 2 Outline • Introduction • Components • Principles • Advantages • Applications Applied Fusion Inc. EBW machine 3 Introduction • First electron beam welding (EBW) machine developed in 1958 by Dr. K. H. Steigerwald, rapidly used in nuclear industries • Electro-thermal advanced manufacturing method • EBW is a fusion welding process fuse welding: join two metal parts together by melting them temporarily & locally in vicinity of contact “heat source” concentrated beam of high-energy e- applied to the materials to be joined 4 Outline • Introduction • Components • Principles • Advantages • Applications Applied Fusion Inc. EBW machine 5 HV Layout (~30-200kV ) Cathode cartridge Bias grid Anode Source Aperture mirror Optical viewing system (alignment) Magnetic lens e- beam column (optics) Deflection coils Collimation/steering Aperture Schematic diagram of EBM/EBW 6 Components: gun • Production of free e- at the cathode by thermo-ionic emission Source: incandescent (~2500C) tungsten/tantalum filament • Cathode cartridge: negatively biased so that e- are strongly repelled away from the cathode • Due to pattern of E field produced by bias grid cup, e- flow as converging beam towards anode; biasing nature controls flow (biased grid used as switch to operate gun in pulsed mode) • Accelerated: high-voltage potential between a negatively charged cathode and positively charged anode 7 HV Layout (~30-200kV ) Cathode cartridge Bias grid Anode
  • Experiment and Simulation of Plasma Window

    Experiment and Simulation of Plasma Window

    Experiment and Simulation of plasma window Kun Zhu,Sheng Huang, Wang shaoze, Yuarong, Zhiyu Guo Physics school of Peking university Institute of Heavy Ion Physics UCANS2015 outline Ø Introduction Ø Plasma window test bench Ø Simulation of plasma window Ø conclusion what is plasma window cathode Arc channel anode Plasm High pressure Vacuum a Traditional solid window beam vacuum Solid window High pressure region Beryllium window Disadvantage: • Thermal damage • Radiation damage • Increase energy loss and energy spread Windowless target Windowless deuterium gas target Expensive differential pump system Complicated vacuum and mechanical system windowless hydrogen gas target for 7Be(p,�) reaction measurement Why plasma window Ø needn’t worry about thermal problem. Ø No radiation damage Ø Very thin equivalent thickness(~nm) Ø Effectively improve the performance of differential pump system Non-vacuum electron beam welding 9mA 25mA Electron beam current after exiting plasma window , Pure helium gas Aperture: 2.36mm Plasma Current: 45A window Air boring and non-vacuum electron beam welding with a plasma window, Ady hershcovitch, Physics of plasma, 12(2005) Deuterium gas target using plasma window Differentially Plasma window Deflector plate pumped gas chamber Beam Roots blower Turbo molecular pump 50kW power supply operating gas pressure is 0.5 bar for argon Diameter of plasma window: 5mm Performance of a plasma window for a high pressured differentially Pumped deuterium gas target for mono-energetic fast neutron Production-Preliminary results, A.De Beer, A. hershcovitch, et. al..NIMB, 170(2000), 259-265 High ion current beam need larger plasma window • Small diameter Plasma window(2-5mm) is successfully used for electron beam welding and gas target.