Bates Linear Accelerator Center - MIT

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P.O. Box 846 Tel: 617/253-9200
Middleton, MA 01949 Fax: 617/253-9599
http://mitbates.mit.edu/
Credits:
Cover design:
Florence Everett
Everett Design
Boston, Massachusetts
Cover Photograph:
(a view from the Bates control room screen)
Richard Pasley Photography
Cambridge, Massachusetts
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Table of Contents
1999 Bates Report
Page
Introduction....................................................................................................................................1-3
Bates 25 Symposium ......................................................................................................................1-5
US Energy Secretary Bill Richardson’s Visit to Bates......................................................................1-6
Milestones....................................................................................................................................1-13
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Measurement of the Elastic Magnetic Form Factor and the Threshold Breakup of 3 He at High
Momentum Transfers .....................................................................................................................2-1
The OOPS Experimental Program ..................................................................................................2-9
Measurement of the Weak Magnetic Moment of the Proton (SAMPLE)........................................2-31
Overview of the BLAST Scientific Program.................................................................................2-39
The CastScan Research Project.....................................................................................................2-43
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Overview........................................................................................................................................3-1
South Hall ......................................................................................................................................3-1
North Hall ......................................................................................................................................3-5
Computing/Data Acquisition ..........................................................................................................3-5
Status of the BLAST Project...........................................................................................................3-7
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Overview...................................................................................................................................... 4-1
Accelerator Operations................................................................................................................. 4-1
Polarized Injector ......................................................................................................................... 4-3
Accelerator and Recirculator........................................................................................................ 4-9
South Hall Ring.......................................................................................................................... 4-10
RF Systems ................................................................................................................................ 4-15
Controls and Instrumentation..................................................................................................... 4-17
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Tours ............................................................................................................................................ 5-1
Open House.................................................................................................................................. 5-1
Other Programs ............................................................................................................................ 5-1
Ph.D. Degrees Granted Based on Data Taken at Bates ...........................................................................5-3
MIT-Bates Ph.D.s ..................................................................................................................................5-5
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1999 Bates Report
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iv
Table of Contents (cont.)
Page
Bates Personnel.............................................................................................................................6-1
Program Advisory Committee......................................................................................................6-2
Approved Experiments .................................................................................................................6-3
Users Group..................................................................................................................................6-4
Users on Currently Approved Experiments..................................................................................6-5
User Institutions on Currently Approved Experiments ................................................................6-7
Publications and Reports ..............................................................................................................6-9

Section 1
Introduction

1999 Bates Report
This report summarizes the scientific and technical progress at the Bates Laboratory over the last
year. It has been a productive period during which data taking on the SAMPLE/hydrogen experiment has
been completed; substantial progress on beam development from the South Hall Ring (SHR) has been
realized; assembly of the OOPS spectrometer system has been largely completed; construction of the
BLAST spectrometer has made substantial progress; and production data taking on SAMPLE/deuterium
is well underway as we go to press.
Following the substantial investment by the Laboratory in the SAMPLE experiment over several
years, it is gratifying to see the high quality data produced by this experiment. The combined data set on
hydrogen and deuterium will provide unique information on the strange quark contribution to the proton’s
magnetism. It will be important for future work worldwide in this area of research.
A significant milestone in the utilization of the stored beam capability with the SHR was reached
last fall with the measurement of elastic scattering from an internal hydrogen gas target at 660 MeV by
the BLAST collaboration. Subsequent development yielded over 200 mA of stored beam. The stored
beam characteristics have been found to be excellent for experiments with internal gas targets. The
lifetimes in the presence of target gas have been determined to be consistent with theoretical expectation.
In the next year we look forward to installation of the Siberian Snake system and the development of
stored, polarized beams.
In February 1999, 8 µA of high duty factor, extracted beam was directed to the B-Line and the
first coincidence (e,e’p) measurement carried out by the OOPS collaboration. During this period
important information on the stability of the beam, the shielding necessary in the South Hall, and the
radiation levels generated was obtained. Further, a scheme to measure the extracted beam position
to ± 0.5 mm has been successfully developed. Next year the first experiment using high duty factor beam
from the South Hall Ring is planned.
With the anticipated completion of the SAMPLE experiments in the next several months, the
Polarized Source Group will have the opportunity to focus on development of polarized beam capability.
A polarized source test bench should be completed in fall 1999, and the group will study strained GaAs
cathodes as well as high power laser systems. These are necessary for optimal utilization of polarized
beams from the South Hall Ring in the coming years.
In the past year the OOPS spectrometer system has been assembled for the first time. This unique
and impressive instrumentation will be utilized in 2000 for important measurements on proton and
deuteron structure. At this time the OOPS collaboration is active in preparing the B-Line and associated
instrumentation for this extended running period.
Over the last year, the BLAST collaboration has made substantial progress. Their efforts in
summer 1998 were essential in the successful operation of the polarized internal gas target and
subsequent studies using stored beam. All branches have made substantial progress with many prototypes
now in operation. The complete set of coils has arrived at Bates, and it is planned that the toroidal
spectrometer will be installed by the end of the year.
A major highlight of the past year was the visit of Energy Secretary Bill Richardson, on April 13,
1999. While his clear support of the Laboratory was evident from his action concerning Bates and the
FY2000 budget process in early February, the Secretary’s visit was a great honor and provided a
memorable day for the Laboratory and its Users. In addition, we were greatly honored by the presence of
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1999 Bates Report
Congressman John Tierney. On pages 1-6 through 1-12 you will find some photographic highlights of
this exciting day.
In closing, it is important to note that 1999 is a special year for the Bates Laboratory. It marks 25
years of beam delivery to experiments in the pursuit of the scientific frontiers and in the education and
training of young physicists. On November 3-5, 1999, a celebration of the past 25 years will be held at
MIT and at Bates. I look forward to seeing you there.
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Richard Milner
August 1999
Middleton, Massachusetts

"Celebrating 25 Years of Beam to Experiment"
Bates25 Symposium
November 3-5, 1999
MIT Bartos Theatre
http://mitbates.mit.edu/bates25/
Confirmed Speakers
Doug Beck, University of Illinois
Elizabeth Beise, University of Maryland
Aron Bernstein, MIT
William Bertozzi, MIT
Kees de Jager, Jefferson Laboratory
J. L. Friar, Los Alamos National Laboratory
Haiyan Gao, MIT
Michel Garçon, CEA/Saclay, France
Donald Geesaman, Argonne National Laboratory
Jochen Heisenberg, University of New Hampshire
Barry Holstein, University of Massachusetts
Richard Milner, MIT
John Negele, MIT
Vijay Pandharipande, University of Illinois
Costas Papanicolas, IASA, Athens, Greece
Gerald Peterson, University of Massachusetts
Michael J. Ramsey-Musolf, University of Connecticut
Robert Redwine, MIT
Hartmut Schmieden, Institut für Kernphysik, Mainz, Germany
Ingo Sick, University of Basel, Switzerland
Paul Souder, Syracuse University
J. F. J. van den Brand, Free University, Amsterdam, the Netherlands
J. W. Van Orden, Jefferson Laboratory
Thomas Walcher, Institut für Kernphysik, Mainz, Germany
1999 Bates Report
This year is the 25th anniversary of the first nuclear physics experiments at Bates: photopion
production in the 14° area. The first high resolution electron scattering measurements with ELSSY were
made a year later. To mark this occasion we are planning two major components:
1) Two receptions: a reception at the MIT Museum on Wednesday, November 3 and a reception
and tour of the Bates Facility on Friday, November 5. Following the Bates reception there will be a
dinner dance at the Sheraton Ferncroft, Danvers. We hope to renew old friendships with employees of
Bates both current and retired, as well as with scientific colleagues -- former students, post docs and
collaborators.
2) A scientific symposium is planned for November 3-5, 1999. The goals of the symposium are
to review the progress in electro-nuclear physics, Bates' contributions to nuclear physics and points to the
future.
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1999 Bates Report
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U.S. Energy Secretary Bill Richardson visited the MIT Bates Linear Accelerator Center on
Tuesday, April 13. Upon his arrival, Secretary Richardson met briefly with MIT Dean of Science Robert
Birgeneau, Director of the Laboratory for Nuclear Science Robert Redwine, Bates Director Richard
Milner, Associate Director Christoph Tschalaer, and U.S. Congressman John Tierney (D-Salem).
Secretary Richardson then met with Ricardo Alarcon (Arizona State University); Douglas Beck
(University of Illinois); Elizabeth Beise (University of Maryland); Jacob Flanz (Mass General Hospital);
William Hersman (University of New Hampshire); June Matthews (MIT); Costas Papanicolas (IASA,
University of Athens); Gerald Peterson (University of Massachusetts); Wade Sapp (American Science &
Engineering); and Adam Sarty (Florida State University). During these discussions the Secretary heard
directly why Bates is important to these experimenters and to their careers.
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(l to r) Bill Richardson, John Tierney, Richard Milner, Patrick Dreher, Ricardo Alarcon, and Robert Redwine
(Photo by S. Sobczynski)

Touring the facility.
(l to r) Richard Milner, Bill Richardson, Robin Staffin, Christoph Tschalaer, and Fabio Casagrande
(Photo by S. Sobczynski)
1999 Bates Report
Ricardo Alarcon (r) explains the BLAST project in the South Hall.
(l to r) Robin Staffin, Richard Milner, John Tierney, Bill Richardson, Robert Birgeneau (Photo by S. Sobczynski)
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1999 Bates Report
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At the SAMPLE experiment in the North Hall Damon Spayde explains current research.
(l to r) Damon Spayde, Robert Carr, Bill Richardson, John Tierney (Photo by S. Sobczynski)
Pushing the button at the OOPS gantry. Richardson and Tierney activate the 120 ton OOPS gantry .
(l to r) John Tierney, Bill Richardson, Adam Sarty (Photo by S. Sobczynski)

1999 Bates Report
In the South Experimental Hall, the Secretary addressed the Bates employees and assured them of
his commitment to Bates. He also stated that the budgetary amendment was officially approved by the
Office of Management and Budget the Monday before his visit.
Secretary Richardson addressing the Bates employees.
(Photo by S. Sobczynski)
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1999 Bates Report
The Peter T. Demos Award for 1998 was awarded to Xiaodong Jiang who received the Ph.D.
from the University of Massachusetts (supervisor Prof. Gerald Peterson) and the BS from the University
of Science and Technology of China.
The Demos Award is given in recognition of outstanding contributions that Peter T. Demos
exhibited for more than three decades as an inspiring teacher, dedicated accelerator builder and laboratory
director, and as a pioneer in electromagnetic research. The Bates Linear Accelerator Center Users Group
established this annual award to be given to the graduate student whose progress in research at the MIT-
Bates Laboratory best exemplifies the spirit, persistence and intellectual qualities that Peter T. Demos
demonstrated in directing and developing the Linear Accelerator Center.
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(l to r) Peter Demos, Richard Milner, Jochen Heisenberg, Bill Richardson, Aron Bernstein, Xiaodong Jiang, John
Tierney(partially hidden), Gerald Peterson and William Turchinetz. (Photo by S. Sobczynski)

1999 Bates Report
This November the Bates Laboratory will celebrate "25 Years of Beam to Experiment" with a
scientific symposium and celebrations. Secretary Richardson honored the achievements of many of the
Bates experimenters.
(l to r) Peter Demos, Raymond Bates (brother of former Congressman William Bates for whom Bates is named), William
Turchinetz, June Matthews, Jochen Heisenberg, William Bertozzi, Aron Bernstein (partially hidden), Toby Smith, Claude
Williamson (partially hidden), Robert Redwine, Gerald Peterson, Anne MacInnis, and Chris Vidal. (Photo by S. Sobczynski)
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1999 Bates Report
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Secretary Richardson’s visit ended with a meeting with many local officials.
(l-r) Mark Kelly, Nancy Jones, Ira Singer, Bill Richardson, and John Tierney. (Photo by S. Sobczynski)

Calendar
Year Milestones
1964 Proposal to AEC for 500 MeV Linac.
1966 Funding of 400 MeV Linac authorized (December 1966).
1999 Bates Report
1967 1. Middleton site acquired.
2. Start of construction authorized by AEC-New York Operations Office (April
1967).
3. Begin building construction (September 1967);
Beam switchyard design; center line waveguide design (to cope with beam
divergence problem demonstrated at SLAC).
4. Let contract for transmitters (Energy Systems, Inc.); Contract for accelerator RF
peripherals (SLAC).
5. Make decision to limit experimental program to electron scattering.
1968 1. Let contract for accelerator waveguide (Varian).
2. Begin design details energy loss spectrometer, ELSSY.
3. Begin design details and specify water, vacuum, electrical systems design.
4. Pursue Litton switchtube difficulty and design change requirements.
1969 1. Building occupied. Begin utilities, vacuum, water systems installation.
2. Complete injector design and initial testing - MIT campus.
1970 1. Accelerator waveguide construction completed and delivered to site; begin
accelerator assembly.
2. Prototype transmitter completed, delivered to site, assembled for acceptance
testing.
3. Let contract for energy loss spectrometer work.
4. Demonstrated pre-injector pulsed beam performance (440 keV, 4000+ pps, 50mA
peak, 20 µsec.).
1971 1. Transmitter prototype accepted.
2. Begin assembly balance of transmitters; begin installation of beam switchyard.
3. Let spectrometer hardware and power supply contracts (Lukens, Grumman, Bath
Iron Works, Alpha).
4. Demonstrate injector 7.5 MeV beam and 100 MeV accelerated beam.
1972 1. Complete assembly of full linear accelerator centerline; mechanical, electrical
assembly of RF transmitters; implementation of basic control system.
2. Complete basic beam transport system to straight-through, 14°, and Spectrometer
Room beam ports.
3. Spectrometer power supply delivered and assembled.
4. Demonstrate 126 MeV accelerated beam (∆ p/p = 0.2% for 80% of beam).
5. Formal establishment of User's Organization (first Chair, H. Crannell).
1973 1. Demonstrate 1% RF 48 hour endurance operation (170 MeV, 3 transmitter
operation).
2. Accelerator brought to 400 MeV capability in preparation for January 1974
demonstration.
3. 14° beam line implemented and installed first phase γπ experiment.
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1999 Bates Report
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1973
(cont.)
4. Carried through horizontal assembly of energy loss high resolution spectrometer
magnet and performed magnetic measurements.
5. Installation underway of spectrometer peripherals, electrical, water, vacuum
systems: spectrometer carriage, focal plane array, target chamber, remaining
vacuum systems, etc., under construction.
6. Dual PDP 11/45 computer data analysis system acquisition initiated.
1974 1. Brief, low duty ratio run of full accelerator, 5 transmitters, 406 MeV: ~ 1 µA beam
current to 14° area.
2. Vertical assembly of high resolution spectrometer completed.
3. 100 hours of ~ 1 µA beam at 125 to 200 MeV energy delivered to first phase γπ
experiment.
1975 1. High resolution spectrometer operating in the "energy loss" mode achieved an
unprecedented 1.1 x 10 -4 resolution.
2. First 16 0(γ,π) data obtained.
1976 1. Development of vertical drift chambers for the electron spectrometer completed.
The new system represented a major advance in the instrumentation of
spectrometer focal plane systems.
2. Construction completed on a fixed angle magnetic spectrometer in the 14° area for
the study of the (γ,π ± ) reaction.
1977 1. 180° scattering facility installed and used for physics experiments.
2. Expansion of laboratory facilities authorized.
3. Fixed angle 250 MeV π 0 detector for experiments in the 14° area.
1978 1. Large diameter beam dumping system installed at the high resolution electron
scattering facility.
1979 1. South Hall and new buildings completed.
2. Authorization received to construct a beam recirculator to increase maximum
beam energy from 410 MeV to 750 MeV.
3. Authorization received by Yale to design and build the polarized source for Bates.
1980 1. First electron beam into the South Hall.
1981 1. Opening angle π 0 spectrometer operational and taking data.
1982 1. Successful operation of the recirculator.
2. Completion of construction of the One Hundred Inch Proton Spectrometer
(OHIPS) and the Medium Energy Pion Spectrometer (MEPS).
3. First electron scattering and pion production experiments in the South Hall.
4. Detailed design of BigBite Spectrometer started.
1983 1. Fabrication and installation of sixth RF transmitter begun. Rework of modulators 2
through 5 started. These projects increased maximum energy to 1060 MeV.
2. Extension of utility building begun.
3. First (e,e'p) experiment.
1984 1. Polarized source moved from Yale to Bates for completion.
2. TIRUS, a Bates-developed very high speed readout system, installed on MEPS.
1985 1. Completion of construction of the BigBite Spectrometer.

1986 1. Completion of electron scattering experiments on tritium.
2. Delivery of polarized electrons for experiments.
3. High intensity pure photon beams available on Beam Line C.
1999 Bates Report
1987 1. Deuteron tensor polarization experiment, 2 H(e,e’d), with a high power liquid
deuterium target.
2. Initiation of advanced accelerator R&D for a pulse stretcher ring.
1988 1. Begin construction of the South Hall Ring (SHR).
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3. Completion of the 12 C Parity Violation Experiment.
1989 1. Begin construction of first generation out-of-plane magnetic spectrometer system.
1990 1. First measurements of quasi-elastic spin response: 3 He(e,e’).
2. First measurement using out-of-plane spectrometer system to obtain longitudinaltransverse
interference response functions.
3. Record high energy for an experiment (903 MeV), record high momentum transfer
(42/fm 2 ), record low cross-section measurement (5 x 10 -40 cm 2 /sr/MeV) for
deuterium electrodisintegration at threshold.
1991 1. First measurement of fifth response function ( 12 C + deuteron), using polarized
electrons and the out-of-plane spectrometer.
2. Measurement of neutron charge form factor, via spin transfer to the neutron, using
the neutron polarimeter.
1992 1. Beam successfully injected into the new Injection Line and transported through
the West Straight Section of the SHR.
1993 1. Beam stored in SHR on first day of storage commissioning. Operation with fullturn
injection of 40 mA (design maximum) demonstrated.
2. Focal-plane proton polarimeter installed in OHIPS.
3. Energy compression system commissioned; factor of ten easily obtained.
1994 1. Demonstrated resonant extraction from SHR.
2. Began major upgrade program for linac and recirculator.
1995 1. SAMPLE experiment takes first data.
1996 1. BLAST funding approved.
2. OOPS satellite supports commissioned. OHIPS reconfigured as electron detector.
3. First (e,e’p) experiment with Out of Plane system.
1997 1. BLAST construction begins.
2. Measurement of 3 He magnetic form-factor to high momentum transfer.
3. Ring commissioning demonstrates 5-minute lifetime of 60 mA stored current at
750 MeV.
4. High intensity and quality SAMPLE beam developed.
1998 1. Measurement of N →∆ transition with OOPS in both π 0 and π + channels.
2. SAMPLE data taking on Hydrogen.
3. First stored beam in SHR on Internal Target.
1999 1. >215 mA of stored beam at 660 MeV in SHR.
2. First 12 C (e,e’p) measurement with high duty factor extracted beam from SHR.
3. SAMPLE data taking on deuterium.
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