Brookhaven 200 MeV Hlinac has been operating for the last 44 years and providing beams to nuclear physics and isotope programs. Three linac upgrades are in progress; (a) to make machine more reliable, (b) to double the intensity by increasing the beam pulse length and, (c) to produce more uniform beam current density on the target by raster the beam on the target.

The construction and initial commissioning phase of a new heavy ion preinjector was completed at Brookhaven in September, 2010, and the preinjector is now operational. This preinjector, using an EBIS source to produce high charge state heavy ions, provided helium and neon ion beams for use at the NASA Space Radiation Laboratory in the Fall of 2010, and gold and uranium beams are being commissioned during the 2011 run cycle for use in RHIC. The EBIS operates with an electron beam current of up to 10 A, to produce mA level currents in 10-40 μs beam pulses. The source is followed by an RFQ and IH linac to accelerate ions with q/m > 0.16 to an energy of 2 MeV/amu, for injection into the Booster synchrotron. The performance of the preinjector is presented, including initial operational experience for the NASA and RHIC programs.

As part of a new heavy ion preinjector that will supply beams for the Relativistic Heavy Ion Collider and the National Aeronautics and Space Administration Space Radiation Laboratory, construction of a new electron beam ion source (EBIS) is now being completed. This source, based on the successful prototype Brookhaven National Laboratory Test EBIS, is designed to produce milliampere level currents of all ion species, with q/m=(1/6)-(1/2). Among the major components of this source are a 5 T, 2-m-long, 204 mm diameter warm bore superconducting solenoid, an electron gun designed to operate at a nominal current of 10 A, and an electron collector designed to dissipate approximately 300 kW of peak power. Careful attention has been paid to the design of the vacuum system, since a pressure of 10(-10) Torr is required in the trap region. The source includes several differential pumping stages, the trap can be baked to 400 C, and there are non-evaporable getter strips in the trap region. Power supplies include a 15 A, 15 kV electron collector power supply, and fast switchable power supplies for most of the 16 electrodes used for varying the trap potential distribution for ion injection, confinement, and extraction. The EBIS source and all EBIS power supplies sit on an isolated platform, which is pulsed up to a maximum of 100 kV during ion extraction. The EBIS is now fully assembled, and operation will be beginning following final vacuum and power supply tests. Details of the EBIS components are presented.

The EBIS based preinjector for both the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL) is now being commissioned at Brookhaven National Laboratory (BNL). In 2008, the RFQ for the project was delivered and commissioned using Test EBIS, which was built to demonstrate the high current EBIS's performance. A dedicated beamline after the RFQ was assembled to confirm the RFQ's performance, and the beam energy was measured by a bending dipole magnet. In November 2009, the RFQ was moved to the final location and the vanes were realigned. The beam commissioning with the RHIC-EBIS was started again during March 2010. The RFQ accelerates ions from 17 keV/u to 300 keV/u and operates at 100.625 MHz. It is followed by a short Medium Energy Beam Transport (MEBT), which consists of four quadrupoles and one buncher cavity. Some temporary diagnostics for this commissioning include an emittance probe, TOF system, fast Faraday cup, and beam current measurement units. As of September 2010, the RFQ and the MEBT show expected performance with He{sup +}, Au{sup 32+} and Fe{sup 20+} beams. Further commissioning for higher intensity beams is in progress.

The NASA SPACE RADIATION LABORATORY (NSRL) has been constructed and started operations at the Brookhaven National Laboratory in 2003. The NSRL facility will be used by NASA to perform radiation effect studies on materials and biological samples for the space program. The facility utilizes proton and heavy-ion beams of energies from 50 to 3000 MeV/n which are accelerated by the AGS_Booster synchrotron accelerator. To date, 1H, 12 C, 56 Fe, 48 Ti, and 197 Au ion beams of various magnetic rigidities have been extracted from the Booster, and transported by the NSRL beam transport line to the sample location which is located 100 m from the extraction point. The NSRL beam transport line has been designed to employ octupole magnetic elements (1) which transform the normal (Gaussian) beam distribution at the location of the sample into a beam with rectangular cross section, and with uniform distribution over the sample. When using the octupole magnetic elements to obtain the uniform beam distribution on the sample, no beam- collimation is applied at any location along the NSRL beam transport line and the beam focusing on the sample is purely magnetic. The main subject of this paper will be the performance of the octupoles (third order optics) in obtaining uniform beam distributions at the target location of the NSRL beam transport line.

Brookhaven's AGS Booster has been modified to deliver slow extracted beam to a new beam line, the NASA Space Radiation Laboratory (NSRL). This facility was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The design of the resonant extraction system has been described. A more detailed description, which includes predictions of the slow extracted beam time structure has been described. In this report we present results of the system commissioning and performance.

We are nearing completion of a project (started in FY 1994) to upgrade the Brookhaven Linac Isotope Producer (BLIP), the 200 MeV Linac and the Hot Laboratory in order to better serve the user community by improving our radioisotope production capacity, reliability and availability. The project technical goals are to increase the proton beam current from 50 {mu}A to 145 {mu}A, provide beam energy variability from 66-200MeV in 21 MeV increments, improve accelerator reliability, and enhance our processing facilities to handle higher levels of radioactivity by adding 2 hot cells, increasing shielding at existing hot cells, and improving ventilation and waste disposal systems. Completion is scheduled for the end of fiscal year 1996. Operation for up to 46 weeks per year will be possible if funding and other resources are made available.

The Brookhaven 200 MeV linac serves as the injector for the AGS Booster, as well as delivering beam to the Biomedical Isotope Resource Center. During the past year, many linac systems have been upgraded to allow operation at 2.5 times higher average current (150 mu A). This was achieved by an increase in rep-rate from 5 to 7.5 Hz, an increase in beam current from 25 mA to 37 mA, and a slight increase in pulse width to similar to 530 mu s. Additional upgrades were made to improve reliability and modernize old systems. This paper describes improvements made in the 35 keV and 750 keV beam transport, 200 MeV beam transport, rf transmission line, rf power supplies, control systems, and instrumentation.

The AGS linac presently accelerates 25 mA of H{sup {minus}} to 200 MeV at a 5 Hz rep-rate and 500 {mu}s pulse width. The Booster takes 4 pulses every 3.8 seconds, and the remaining pulses are used for isotope production. The authors are in the process of upgrading the linac to increase the average current delivered for isotope production by more than a factor of two, while at the same time expecting to decrease linac downtime. Various aspects of this upgrade are discussed, including the upgrade of the control system, new high power transmission line, transport line vacuum, and rf power supply system upgrades.

The Band II RF system was originally built to support the Booster operations during the acceleration of heavy ions. Designed to sweep from 0.6 to 2.5 MHz, it was build and successfully tested over a much broader range reaching 4 MHz. Voltages up to more than 20 kV were reached over the design frequency range. The system consists of two stations, each of which is made of one single gap cavity directly driven by a grounded cathode push pull power amplifier. The low Q high permeability ferrites needed in the coaxial cavity in order to reach the lower end of the band make tuning extremely easy. Both systems were thoroughly tested both at single frequencies and on a sweep and are now installed in the ring,ready for operations. Static measurements showed no high-loss effects. The results of the “bench” tests that lead to important performance improvements are given

load and the NSLS is at the 69 KV level. However, on the days that the interference was first observed at the NSLS only one-half of the substation transformers at Temple Place were in service. The 13.8 KV tie breaker was closed and the full substation load was supplied from this common bus. Thus the coupling between the pulsating magnet load and the NSLS was at the 13.8 KV level. Establishing the normal two bus configurations at Temple Place appeared to reduce the disturbance. These events suggested a controlled experiment to measure the magnet power swing and the induced powerline flicker; and from these measurements project the flicker on the lab site generated by the Booster operating at full energy. This experiment could corroborate the validity of the electrical models used in analyzing the power flow from the LILCO power grid and its distribution on the Lab site described in Accelerator Division Technical Note 220.

A high-level RF system, including a power amplifier and cavity, has been designed and built for the Alternating Gradient Synchrotron (AGS) Booster. It covers a frequency range of 2.4 to 4.2 MHz and will be used to accelerate high-intensity protons, low-intensity polarized protons and heavy ions to the 1.5-GeV level. A total accelerating voltage of up to 90 kV will be provided by two cavities, each having two gaps. The internally cross-coupled, pushpull cavities are driven by an adjacent power amplifier. In order to accommodate beam intensities of up to 0.75*10/sup 13/ protons per bunch, a low plate resistance power tetrode is used. The tube anode is magnetically coupled to one of the cavity's two parallel cells. The amplifier is a grounded cathode configuration driven by a remotely located solid-state amplifier. It has been tested in the laboratory at full gap voltage with satisfactory results.<>

A fixed-frequency, 930-MHz harmonic cavity has been installed in the alternating gradient synchrotron (AGS) ring. The primary purpose of this harmonic cavity is to increase (dilute) the longitudinal phase space area occupied by the beam by as much as a factor of four (to 4.0 eV-s) in a controlled, rapid manner while maintaining a smooth local density. This will then permit essentially lossless passage through transition energy (8.0 GeV) at intensities higher than previously achieved. Although the system controls permit as many as five dilutions per AGS cycle, only one is used at present. Effects of the various phase modulation programs, excitation period, and RF voltage programs on the dilution rate have been modeled. The parameters predicted to yield the best dilution have been implemented with satisfactory results. Further, the parameter space is being explored experimentally in order to determine the programs leading to the desired degree of dilution without loss of beam in the minimum time.< >

A harmonic cavity at 93 MHz is being built that will be used in the Brookhaven AGS to perform a controlled blow up of the longitudinal phase space in order to facilitate lossless passage through the transition energy. The phase space area will be increased from 1.0 eV- s to as much as 4.0 eV-s on two 50 ms magnetic field flattops. The cavity is a shorted quarter wave TEM mode cavity that provides 30 kV of gap voltage for less than 10 kW of drive power. When the cavity is not in operation it will be switched to a low-impedance state by a PIN diode switch. 5 refs., 3 figs., 1 tab.

The BNL 200 MeV Linac normally accelerates H/sup -/ ions during its operating schedule. During selected periods, typically of six to ten weeks duration, polarized H/sup -/ ions are accelerated. Since linac H/sup -/ commissioning, longer 7835 tube lives have been recorded and after initial operating bugs were eliminated, preinjector reliability has improved. Hardware components in the Preinjector, rf system, and ion source have been replaced or upgraded, and plans are being implemented for future system improvements. BLIP operations were initially curtailed during polarized beam running and a pulsed magnet has been installed in LEBT to restore BLIP running time to original levels.

The AGS Polarized Beam Project was started in 1980. The first beam was accelerated in March 1984, followed by commissioning studies and a high energy physics run at 16.5 GeV at an average 30% polarization. The Linac portion of the project included a new polarized H- ion source and a Radio-Frequency Quadrupole (RFQ). These will be described as will the design of the new Low Energy Beam Transport (LEBT) line and beam instrumentation for the Linac. Operational results, cuirrent status and future plans will be discussed.

Planning for the conversion of the AGS Linac to H/sup -/ acceleration was begun in 1979; installation was completed in 1983. Discussion of this work and of the operational experience will be presented. The AGS Polarized Beam Project was begun in 1980. The design of the new H/sup -/ polarized source, the low Energy Beam Transport line (LEBT), and Radio-Frequency Quadrupole (RFQ) will be described. Current status and future plans will be presented. 14 references, 5 figures.