Crebbin, Kenneth C.

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Lawrence Berkeley National LaboratoryRecent WorkTitleBEVATRON OPERATION AND DEVELOPMENT. 46 April through June 1965Permalinkhttps://escholarship.org/uc/item/78j1q4bzAuthorCrebbin, Kenneth C.Publication Date1966-02-16eScholarship.org Powered by the California Digital LibraryUniversity of California·· UCRL-16553 University of California Ernest· 0. ~lawrence Radiation · Laboratory ,. BEVATRON OPERATION AND DEVElOPMENT. 46 April through June 1965 TWO-WEEK LOAN COPY This is a Library Circulating Copy which may be borrowed for two weeks. For a personal retention copy, call Tech. Info. Diuision, Ext. 5545 DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof or the Regents of the University ofCalifornia. '·iii Research and D evelopment UNIVERSITY OF CALIFORNIA Lawrence Radiation Laboratory Berkeley, California AEC Contract No. W -7405-eng-48 UCRL.., 16553 UC 28 Particle Accel. and High Volt.. Mach. TID-4500 (47th Ed.) BEVATRON OPERATION AND DEVELOPMENT. 46 April through June 196 5 Kenneth C .. Crebbin February 16, 1966 Printed in USA. Price $1.00. Available from the Clearinghouse for Federal Scientific and Technical Information, National Bureau of Standards, U. S. Department of Commerce, Springfield, Virginia. • -iii-BEVATRON OPERATION AND DEVELOPMENT. Abstract I. Ope ration II. Shutdown April through June 196 5 Contents III. Bevatron Development and Studies IV. Experimental Program . V. Magnet and Power Supply Staff References >!<Preceding Quarterly Reports: UCRL-16204, UCRL-16203. 46 UCRL-16553 v 1 1 3 3 4 4 8 'Jc -v- UCRL-16553 BEVATRON OPERATION AND DEVELOPMENT. 46 April through June 196 5 Kenneth C. Crebbin Lawrence Radiation Laboratory University of California Berkeley, California February 16, 1966 ABSTRACT " The Bevatron provided beam for physics research 85% of the scheduled operating time. The first extraction magnet in the external proton beam system was replaced because of a short to ground. Two pri-mary experiments were ended this quarter, one primary experiment was continued through this quarter, and one new primary experiment was started. Ill -1- UCRL-16553 I. OPERATION The Bevatron operation record is shown in Fig. 1. The beam was on for 85o/o of the scheduled operating time. The beam was off for 8o/o of the time because of equipment failure and 7o/o of the time for experimental setup, tuning, and routine checks. The external-proton-beam-extraction magnets have a ground current protection device that turns the power supplies of£ if any shorts to ground develop and ground current starts to flow. This protects the vacuum seals and vacuum skin of the Bevatron from carrying high currents. Early in April our first extraction magnet, M 1, developed a short to ground. In-vestigation of this short indicated it to be at the vacuum feed-through or in-side the Bevatron vacuum system, most likely associated with the M 1 magnet itself. The ground protection circuit was modified to allow operation with the existing short but to still provide protection if a larger ground cur-rent flowed. The resistance of the short seemed to vary as the magnet (M 1) was pulsed. We decided to operate the magnet de rather than pulsed. The maximum current was reduced to 1300 amperes de from 1500 to 1600 amperes peak pulsed. At maximum energy of extraction (6. 2 BeY) we compensated for this reduction in current by reducing the radial separation of the two extraction magnets M 1 and M 2. As the first quadrupole (Q 1) also affects the radial displacement of the extracted beam, additional radial deflection was gained by increasing th€ current in Q 1. We were able to run the external proton beam in this manner with only a slight reduction in extraction efficiency until the shutdown on May 30. II. SHUTDOWN The normal 8-hour maintenance-day on.April 12 was extended into a 2-day shutdown to install the beam transport system for the SLAC - LRL experiment in the 72-inch hydrogen bubble chamber. The beam transport system was installed from the external-beam first focus area to the 7 2-inch bubble chamber. Other shutdown work was devoted to routine maintenance and installation jobs. There was a scheduled 3-week shutdown from May 30 through June 19. During this 3- week period we operated on a three-shift Monday-through-Friday schedule. We returned to our normal three-shift seven-day-a-week schedule on June 20. There were two major jobs during this shutdown. The first was the installation of the new motor control circuit for the main motor generators. w The details of this new system will be covered in the next Bevatron Quarterly Report. 1 The second major job was the repair of the short to ground in the M 1 magnet or feed-through of the external proton beam extraction system. At the start of the vacuum shutdown the M 1 magnet and feed-through were inspected to pinpoint the short. Pushing on the ground plane of the magnet caused the resistance of the short to change. Examination of the magnet disclosed many cracks in the epoxy insulation of the coil and a large quantity of metal chips in and about the magnet. These chips came from wear of the overhead support and guidance system. Vacuum cleaning in the region of the ground plane also changed the resistance of the ground short. We made the Actual beam ON time 0 ExperiJ!'entol setup t1me checks a tuning VIlA 0 FF time due to ~ coroponent failure ~100 ~ 90 ~ ~ 80 ~ K:l ~ 0 ~ 60 <::s ~50 l(j ~ 40 ~ ~ 30 ~ 20 ~ 10 ~ ~ c::: ~ .g ........ ~ ~ Week of Crew hours 4/4 o/!1 4A8 ~5 5/2 5/g 5A6 5h3 5ho 616 6/13 6/20 6/21 168 Turn on 8 maintenance time (h) 1 o Scheduled operating time (h) 146 Scheduled Bevatron test time (h) 6 Scheduled shutdown time (h) 16 Hoi iday (h) o 144 168 168 168 168 168 168 12 9 II 8 9 10 10 81 1·4 37 24 152 146 7 II 9 0 0 0 149 143 II 16 0 0 0 0 140 146 18 12 0 0 0 0 144 120 120 168 168 0 0 0 0 8 24 0 0 0 108 0 0 0 0 52 120 120 120 168 0 24 0 0 0 0 M U B-9686 Fig. 1. Summary of Bevatron operation for April through June, 1965. • 3. .;:: -I N I c:: 0 :;d l' I ,_,.. "' Ul Ul v.> ·~· . ,. -3- UCRL-16553 decision to replace the M 1 magnet with a spare. Subsequent examination showed that the metal chips had gotten into cracks in the e;poxy insulation on the magnet windings and shorted the windings to ground. It is possible that the cracks in the epoxy were caused by radiation damage, although there is no way to be certain. The radiation level at the surface of the M 1 magnet was about 18 R. This made the allowable work time per man in the area fairly short. Each step was carefully planned ahead to maximize the man effort in actually re-moving and replacing the magnets. If this had not been done, we would have run out of people before .the job was completed. The deflection magnet,. M 1, and quadrupole magnet, Q 1 .. were removed as a unit. Before the work began this unit and associated parts, as well as other high-level radiation sources in the tangent tanks, were shielded as well as we could manage, and as much work as possible was done outside the Bevatron tank. The new M 1 and new Q 1 were preassembled on their carriage prior to in-stallation in the Bevatron. 2.-4 In the past we have had some misalignment problems with the support and guidance system of M 1 and Q 1. To help correct this problem a new, more rugged overhead support structure was built. In addition to providing a more rigid support, this as sernbly provides better position ad-justments for the fina.l magnet alignment in the Bevatron, A rubber sheet was installed on top of the M 1 magnet to protect it from any falling chips that may come from wear caused by misalignment. The design of the Q 1 magnet pr.ovid.ed adequate protection from this prob-lem, so no additional protection was necessary . . ill. BEVATRON DEVELOPMENT AND STUDIES Most o£ the s;.tudy period~> this quarter were devoted to injector tuning, emittance tests, amd Bevatron acceptance tests. The bulk of the effort was devoted to improving and expanding our diagnostic equipment. There are no details to rep01:rt at this time, Some periods were used to study com.pa.tibility and beam.- sharing problems, particularly problems having to do with beam sharing on two and three targets in the external proton beam channel. The findings in these tests were that it was possible to sha.re beam between tw·o ox three targets under some oper·ating conditions . At any given tim,e the experimenters 1 beam req;,.JJ.irements would determine what mode of beam e.haring was possible. IV. EXPERIMENTAL PROGRAM The Crowe Group 1 s K+ decay-spectra experiment was continued through tb.is qua:rter. The Lofgren G:r.oup 1 s p=·p scattering experiment was ended early i:n. May, and the Trilling-Goldhabet Group 1 s experiment studying the decays and strong interactions wit~li. Kg mesons in the 25-inch hydrogen bu.bble chamber was ended with shutdown on May 30. A new primary experiment was started,at the EPB first focus. This was the SLAC- LRL experiment {No. 41). This new beam channel selects secondary pa~ticles a..t a mean production angle of 7-1/2 deg. This particu-lar experiment is a. study of inelastic nu.cleon-nucleon interactions in the 72-inch hydrogen bubble chamber over an energy range of 4.5 to 6.0 BeV. -4- UCRL-16553 A summary of the experimental program for this quarter is shown in Table I. V. MAGNET POWER SUPPLY Th.e magnet pulsing record is shown in Table II. E. J. Lofgren Walter D. Hartsough Kenneth C. Crebbin Fred H. G. Lothrop Wendell Olson William Everette Duward S. Cagle Frank W. Correll Robert G. Gisser William H. Kendall G. Stanley Boyle Robert W. Brokloff Ashton H. Brown Gary M. Byer Norris D. Cash Donald N. Cowles Ferdinand Dagenais James R. Guggemos Carles H. Hitchen Arthur K. !kuma. William J. Meserve Robert M. Miller Joseph F. Smith Harvey K. Syversrud Marsh M. Tekawa Robert W. Allison, Jr. Trancuilo Canton Warren #. Chupp Bruce Cork Kenneth C. Crebbin Tom Elioff Robert Force Leroy T. Kerth Fred H. G. Lothrop Donald Milberger Robert Richter Glenn White William A. Wenzel Emery Zajec STAFF Bevatron Group Leader In charge of BevatrOJ:l operations } Operation supervision Radiation control } Operating cn;w supervisors Bevatron Operators Development and support / ( )> Table I. Summary of Bevatron experimental research program, April through June 1965 Group Internal groups Lofgren (No. ZOa)a Crowe (No. ZZ) Trilling-Goldhaber (No. Z7) Murray (No. 39) Alvarez (No. 45) Segre-Chamberlain (No. 41) External groups U. of Carolina (Childs) SLAC (No. 41) (Perl) Experiment dates Start End 1-13-65 5-6-65 1Z-13-64 3-13-65 1Z-11-64 In progress In progress 3-3-65 5-30-65 Z-11-65 5-Z8-65 5-7-6 5 5-7-65 4-Z7-65 In progress 5-Z7-65 5-Z7-65 4-Z7-65 In progress a. Numbers in parentheses are experiment numbers. Experiment p-p Scattering K+ Decay spectra K~ in Z5 inch bubble chamber Septum separator tests Tuneup for future scheduled experiments Scatter p+ in 7Z-inch Hz bubble chamber Crystal exposure Scatter p+ in 7Z-inch Hz bubble chamber Beam time This quarter (Apr.-June 1Z-h periods 5 0 67 0 8Z 0 0 5 0 1 44 7 1/Z 44 7 Hours 48 0 725 0 839 0 0 73 0 5 476 67 476 67 From start through June 1965 1Z-h periods 79 zo 90 39 97 Z1 0 11 0 1 44 7 1/Z 44 7 Hours 79Z Z40 979 4Z4 988 Z09 4 143 0 5 476 67 476 67 f Pulse schedule 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 1:1 .. Primary or secondary experiment p s p s p s p s p s p s p p s I U1 I c () ~ l' I ~ 0' U1 U1 l;.l Table II. Bevatron motor-generator set monthly fault report. 4 to 6 pulses per minute 7 to 9 pulses per minute 10 to 17 pulses per minute 150.0 to 6900 A 7000 to 9000 A 1500 to 6900 A 7000 to 9000 A 1500 to 6900 A 7 000 to 9000 A Faultsa Faults a Pulses I Faultsa Pulses Faults a I a Pulses Faults a Month Pulses Pulses Pulses / Faults (1965) 14 1 26 14 126 14 I 26 14 26 '14 26 14 26 I Jan. 1,566 1, 732 ! I I 2,397 2 26,909 246,571 19 42 ; Feb. 4,501 1,358 I 1: I ! 10,422 89,963 ·! 4 168,801 14 31 : ; I March 1 .454 I ! 246,308; 10 10 145,517 22 30 I April 245 I I 49,942 2 ! 2 160,776· 12 28 11,422 2 i I : I May 2,539 ! I 4,039 I ! 2,071 1 : 310,039 16 35 34,413 I 41 6 l i I I June 10,095 ! i 272 I 945 ! i 1,496 i 68,818 2! 5 3,317 i ! I i : July. l I I ! ! i i I Aug. ! I I ! : I i I ! Sept. i ! I l I Oct. i I Noir. i I Dec. I ____L_ ___ ______L___ a 14 indicates an arc-back, 26 indicates an arc-through. ( .. Totals Faults Pulses Arc-1. Arc-(P) backs . through 279,175 21 I 42 I 27 5,045 18 35 392,279 32 40 222,385 I 14 I 32 353,155 21 41 84,943 2 5 ! l I ' I L___ ------ ' Total P/F (F) I 63 4431 I 53 : 5189 172 : 5448 1 46 i 4834 i 62 : 5696 ! 7 112,135 i l I ! j ' ' ---~ ·~ Comments --!; I "' c:: () !XI t"' I ..... "' I.TlI.Tl l.V - 7- UCRL-16553 Edward Hartwig } In charge of Electrical Engineering Group Robert Force Marion Jones In charge of Electrical CoordinationGroup () Harold Vogel In charge of Motor Generator Group '-,.1, Donald' Milberger In charge of Electrical Maintenance Group Kenow Lou } Cedric Larson In charge of Mechanical Engineering Group Abraham Glicksman -8- UCRL-16553 REFERENCES 1. Kenneth C. Crebbin and Robert Frias, Bevatron Operation and Development. 47 ·' July through September 1965, UCRL-16554. 2. Kenneth C. Crebbin, Robert Frias, William L. Everette, and Walter D. Hartsough, Bevatron Operation and Development. 41, January through March 1964, UCRL-11560; July 1964. 3" Kenneth C. Crebbin, William L. Everette, and Walter D. Hartsough, Bevatron Operation and Development. 40, October through December-1963, UCRL-11383, July 1964. 4. Kenneth C. Crebbin, William L. Everette, Calvin. F. Hansen, and Harold W. Vogel, Bevatron Operation and Development. 39, July through September 1963, UCRL-11279, April 1964. j.r •• This report was prepared as an account of Government sponsored work. Neither the United States, nor the Com-mission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, appa-ratus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any infor-mation, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Com-mission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee .of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor . 

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BEVATRON OPERATION AND DEVELOPMENT. 46 April through June 1965

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BEVATRON OPERATION AND DEVELOPMENT. 46 April through June 1965

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