Milestones

• Proposal to AEC for 500 MeV Linac

• Funding of 400 MeV Linac authorized (December 1966)

• Middleton site acquired

• Start of construction authorized by AEC-New York Operations Office (April 1967)

• Begin: Building construction (September 1967). Beam switchyard design. Center-line waveguide design (to cope with beam
blowup problem demonstrated at SLAC)

• Let: Contract for transmitters (Energy Systems, Inc.);Contract for accelerator RF peripherals (SLAC)

• Make decision to limit experimental program to electron scattering

• Let contract for accelerator waveguide (Varian)

• Begin design details energy loss spectrometer, ELSSY

• Begin design details and specify water, vacuum, electrical systems design

• Pursue Litton switchtube difficulty and design change requirements

• Building occupied. Begin utilities, vacuum, water systems installation

• Complete injector design and initial testing – MIT campus

• Accelerator waveguide construction completed and delivered to site; begin accelerator assembly

• Prototype transmitter completed, delivered to site, assembled for acceptance testing

• Let contract for energy loss spectrometer work

• Demonstrated pre-injector pulsed beam performance (440 keV, 4000+ pps, > 50 milliamps peak, > 20 µsec)

Transmitter prototype accepted

Begin assembly balance of transmitters; begin installation of beam switchyard

Let spectrometer hardware and power supply contracts (Lukens, Grumman, Bath Iron Works, Alpha)

Demonstrate injector 7.5 MeV beam and 100 MeV accelerated beam

• Complete assembly of full linear accelerator centerline; mechanical, electrical assembly of RF transmitters; implementation of basic control system

• Complete basic beam transport system to straight-through 14° and Spectrometer Room beam ports

• Spectrometer power supply delivered and assembled

• Demonstrate 126 MeV accelerated beam (delta p/p = 0.2% for 80% of beam)

• Formal establishment of User’s Organization (first Chairman, H. Crannell)

• Demonstrate 1% RF 48 hour endurance operation (170 MeV, 3 transmitter operation)

• Accelerator brought to 400 MeV capability in preparation for January 1974 demonstration

• 14° beam line implemented and installed first phase gamma-pi experiment

• Carried through horizontal assembly of energy loss high resolution spectrometer magnet and performed magnetic measurements

• Installation underway of spectrometer peripherals, electrical, water, vacuum systems: spectrometer carriage, focal plane array, target chamber, remaining vacuum systems, etc., under construction

• Dual PDP 11/45 computer data analysis system acquisition initiated

• Brief, low duty ratio run of full accelerator, 5 transmitters, 406 MeV: ~ 1 µA beam current to 14° area

• Vertical assembly of high resolution spectrometer completed

• 100 hours of ~ 1 µA beam at 125 to 200 MeV energy delivered to first phase gamma-pi experiment

• High resolution spectrometer operating in the “energy loss” mode achieved an unprecedented 1.1 x 10**-4 resolution

• First 16O(gamma, p) data obtained

• 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

• Construction completed on a fixed angle magnetic spectrometer in the 14° area for the study of the (gamma, pi±) reaction

• 180° scattering facility installed and used for physics experiments

• Expansion of laboratory facilities authorized

• Fixed angle 250 MeV pi° detector for experiments in the 14° area

• Large diameter beam dumping system installed at the high resolution electron scattering facility

• South Hall and new buildings completed

• Authorization received to construct a beam recirculator to increase maximum beam energy from 410 MeV to 750 MeV

• Authorization received by Yale to design and build the polarized source for Bates

• First electron beam put into the South Hall

• Opening angle pi° spectrometer operational and taking data

• Successful operation of the recirculator

• Completion of construction of the One Hundred Inch Proton Spectrometer (OHIPS) and the Medium Energy Pion Spectrometer (MEPS)

• First electron scattering and pion production experiments in the South Hall

• Detailed design of BigBite spectrometer started

• Fabrication and installation of sixth RF transmitter begun. Rework of modulators 2 through 5 begun. These projects will increase maximum energy to 1060 MeV

• Extension of utility building begun

• First (e,e’p) experiment

• Polarized source moved from Yale to Bates for completion

• TIRUS, a Bates-developed very high speed readout system, installed on MEPS

• Completion of electron scattering experiments on tritium

• Completion of construction of the BigBite spectrometer

• Delivery of polarized electrons for experiments

• High intensity pure photon beams available on Beam Line C

• Deuteron tensor polarization experiment, 2H(e,e’d), with a high power liquid deuterium target

• Initiation of advanced accelerator R&D for a pulse stretcher ring

• Begin construction of the South Hall Stretcher Ring (SHR) with commissioning scheduled for 1992

• Installation of the Moeller polarimeter on Beam Line B

• Completion of the 12C Parity Violation Experiment

• Begin construction of first generation out-of-plane magnetic spectrometer system

• First measurements of quasi-elastic spin response: 3He(e,e’)

• First measurement using out-of-plane spectrometer system to obtain longitudinal-transverse interference response functions

• 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

• First measurement of fifth response function (C12 + deuteron), using polarized electrons and the out-of-plane spectrometer

• Measurement of neutron charge form factor, via spin transfer to the neutron, using the neutron polarimeter

• Beam successfully injected into the new Injection Line and transported through the West Straight Section of the SHR

• Beam stored in SHR on first day of storage commissioning. Operation with full-turn injection of 40 µA (design maximum) demonstrated

• Focal-plane proton polarimeter installed in OHIPS

• Energy compression system commissioned; factor of ten easily obtained

• Demonstrated resonant extraction from SHR

• Began major upgrade program for linac and recirculator

• SAMPLE experiment takes first data

• BLAST funding approved

• BLAST construction begins

• Measurement of 3He magnetic form-factor to high momentum transfer

• Ring commissioning demonstrates 5 minute lifetime of 60 mA stored current at 750 MeV

• High intensity and quality SAMPLE beam developed

• Measurement of n -> Delta transition with OOPS in both pi° and pi+ channels

• SAMPLE data taking on Hydrogen

• First stored Beam in SHR on Internal target

• Over 200 mA in South Hall Ring

• SAMPLE data taking on Deuterium

• Completion and commissioning of OOPS spectrometer

• VCS experiment: uses high duty factor beam and full OOPS spectrometer

• SAMPLE results published in Science

• OOPS running with extracted unpolarized CW beam, energies from 570 to 670 MeV, currents up to 10 μA, extraction efficiency 80 to 94%

• 60 kV test setup for preparation and certification of polarized electron guns

• Compton Polarimeter installed in SHR; back-scattered photons detected

• Beam energy of 1 GeV achieved, with 14 mA peak current

• OOPS running with extracted polarized CW beam, energy 950 MeV, current 10 μA, extraction efficiency 90%, duty factor 65%

• Stored polarized beam in the SHR using Siberian Snake; 670 MeV, 50 mA, 30 minute lifetime

• First observation of stored polarized electron beam spin flip using a prototype RF dipole

• Fiber-coupled diode laser installed in polarized source

• Completion of SAMPLE running at 125 MeV on deuterium

• Completion of OOPS running

• BLAST assembly and magnetic field mapping

• Strained GaAs photocathode and diode laser used to produce highly polarized electron beam (>60%), stored in SHR; 850 MeV, 100 mA, 40 minute lifetime

• 98% efficient spin flip achieved using a second RF dipole

• Installation of BLAST neutron detectors

• BLAST commissioning, with beam quality monitors used to optimize beam tune

• Compton Polarimeter commissioned for operation with beam currents above 200 mA

• Atomic Beam Source installed; first polarized internal target in the SHR

• BLAST deuterium and hydrogen running. High target vector polarizations (>80%) achieved with installation of a collimator upstream of the target cell

• Low-momentum compaction lattice used in SHR to reduce bunch length to 3.6 ps

• BLAST data taking optimized with a second-level trigger and front-end buffering

• Wire chamber and coincidence rates used to further improve beam tune. Beam lifetimes of 25 minutes with target gas achieved routinely

• BLAST deuterium running completed

• Coherent synchrotron radiation in SHR detected near 100 GHz

• MIT takes ownership of the Bates facility