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Design of a versatile ESQ transport system

Description: A versatile precision beam transport channel was built with inexpensive parts requiring minimum precision machining. The critical items, an optical bench and sliding bases are commercially available standard items. The only important precision machining is illustrated, where a small section of an optical bench is used as a quadrupole assembly holding fixture. With this type of fixturing there is no loss of precision during the transfer of the quadrupole assembly from the EDM setup onto the final assembly, other than the manufacturer-specified mounting and dismounting tolerance. Displacement measurements of the pole tips taken on ten different quadrupole assemblies determined that RMS displacement in the x direction was .000307 and in the y direction was .000290. The actual performance of this system will be presented in other papers at this conference by A.W. Maschke and E.F. Meier.
Date: January 1, 1983
Creator: Brodowski, J.
Partner: UNT Libraries Government Documents Department

MEQALAC rf accelerating structure

Description: A prototype MEQALAC capable of replacing the Cockcroft Walton pre-injector at BNL is being fabricated. Ten milliamperes of H/sup -/ beam supplied from a source sitting at a potential of -40 kilovolt is to be accelerated to 750 keV. This energy gain is provided by a 200 Megahertz accelerating system rather than the normal dc acceleration. Substantial size and cost reduction would be realized by such a system over conventional pre-accelerator systems.
Date: January 1, 1981
Creator: Keane, J. & Brodowski, J.
Partner: UNT Libraries Government Documents Department

Space charge limits in ESQ transport systems

Description: This report describes the results obtained in a series of experiments done with a variety of different electrostati quadrupole configurations, using the precision optical bench system.
Date: January 1, 1983
Creator: Maschke, A.W.; Brodowski, J. & Meier, E.
Partner: UNT Libraries Government Documents Department

Magnets for the national spallation neutron source accumulator ring

Description: The National Spallation Neutron Source Accumulator Ring will require large aperture dipole magnets, strong focusing quadrupole magnets, and smaller low field dipole, quadrupole, and sextupole correcting magnets. All of the magnets will provide a fixed magnetic field throughout the accumulator`s fill/storage/extraction cycle. Similar fixed field magnets will also be provided for the beam transport systems. Because of the high intensity in the accumulator, the magnets must be designed with high tolerances for optimum field quality and for the high radiation environment which may be present at the injection/extraction areas, near the collimators, and near the target area. Field specifications and field plots are presented as well as planned fabrication methods and procedures, cooling system design, support, and installation.
Date: July 1, 1997
Creator: Tuozzolo, J.; Brodowski, J. & Danby, G.
Partner: UNT Libraries Government Documents Department

The RHIC accelerating cavity prototype tuner

Description: The RHIC Accelerating System runs at 26.7 MHz and is required to have an operating range of 85 kHz during the acceleration cycle. Since it also must provide sufficient range to cover manufacturing errors and temperature variation, a requirement of 300 kHz has been specified. A mechanical approach acting on the cavity accelerating gap has been chosen for financial reasons over a ferrite approach. A prototype has been constructed and fully tested on the existing test cavity, using the tuning loop feedback circuitry developed for this task. Results from both the loop response and the power tests of the prototype indicate that this design will successfully meet the performance requirements for the RHIC Accelerating Cavity.
Date: May 1, 1995
Creator: Ratti, A.; Brennan, J.M.; Brodowski, J.; Onillon, E. & Rose, J.
Partner: UNT Libraries Government Documents Department

First results on BNL H/sup -/MEQALAC

Description: The MEQALAC (Multiple-Beam Electrostatic Quadrupole Array Linear Accelerator) concept and its first experimental test have been described previously. The test verified that a MEQALAC can transport and accelerate multiple, high brightness beamlets starting at very low initial ..beta..(5 x 10 /sup -4/ in the test). The six-dimensional phase space density per beam, (anti i/fez)/(epsilon/sub NL/ epsilon/sup 2//sub NL/) was 3.3 x 10/sup 29//m/sup 3/-rad/sup 3/. This paper describes initial results of a second MEQALAC test which explore higher frequency operation with smaller bore size. The current density was higher by up to a factor of seven. This MEQALAC was a four beam H/sup -/ accelerator. Conceivably, it could lead to a replacement for relatively bulky and expensive Cockcroft-Walton pre-injectors.
Date: January 1, 1981
Creator: Gammel, G.; Brodowski, J.; Dobbs, K.; Keane, J.; Maschke, A.; Meier, E. et al.
Partner: UNT Libraries Government Documents Department

Low beta accelerating system for heavy ions

Description: To investigate the performance that can be achieved for low energy heavy ion particle acceleration, a two megahertz low beta linac is being built. This structure, intended for acceleration of 260 keV xenon or 400 keV mercury, is comprised of a quarter wavelength parallel plate resonator used to support drift tubes forming a ..beta.. lambda/2 structure. The 20 gap accelerator, to be driven by a 30 kilowatt transmitter, will provide 10 milliamperes of mercury ions at the 1.8 MeV energy level. Focussing is achieved by a unique arrangement of electrostatic quadrupoles.
Date: January 1, 1979
Creator: Bertsche, A.; Brodowski, J.; Keane, J.; Maschke, A.W. & Sanders, R.
Partner: UNT Libraries Government Documents Department

A fast chopper for programmed population of the longitudinal phase space of the AGS

Description: A fast beam chopper has been built that can produce an arbitrary pulse program of the 200 MeV H/sup /minus// beam for synchronous injection into moving rf buckets in the AGS. The chopper will eliminate rf capture losses and can be used to tailor the initial distribution in longitudinal phase space by varying the pulse parameters, width and phase, on a bunch-by-bunch time scale, during multi-turn injection. The chopper also serves as a studies tool since it can provide controllable beam intensity with fixed longitudinal emittance (and conversely) and/or missing bunches. It is an electrostatic deflection device with 15 pairs of plates located above and below the 35 keV H/sup /minus// beam between the ion source and the RFQ preinjector. The plates are space 26 mm apart in the beam direction and connected as a slow-wave structure by coaxial cables. They are driven to +- 760 V by dc-coupled pulse generators. Beam current rise and fall times are less than 10 ns. 3 figs.
Date: January 1, 1989
Creator: Brennan, J.M.; Ahrens, L.; Alessi, J.; Brodowski, J.; Kats, J. & van Asselt, W.
Partner: UNT Libraries Government Documents Department

500 kV mercury accelerator

Description: The objective of building a low-cost pre-accelerator for low energy heavy ion particle accelerator was realized by using standard, readily available material and hardware. Some savings were obtained in the construction of the dome by avoiding welding, expensive metal spinnings and unnecessary corona rings. Larger monetary economies were realized by unique approach to building the high voltage column utilizing a glass tube.
Date: January 1, 1979
Creator: Brodowski, J.; Maschke, A.W.; Mobley, R.M.; Keane, J.T. & Meier, E.
Partner: UNT Libraries Government Documents Department

Beam position monitoring in the AGS Linac to Booster transfer line

Description: A beam position monitor system has been developed and used in the commissioning of Brookhaven's Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper will provide a system overview and report results from the commissioning experience.
Date: January 1, 1991
Creator: Shea, T.J.; Brodowski, J. & Witkover, R.
Partner: UNT Libraries Government Documents Department

MEQALAC development at Brookhaven

Description: A novel method of transporting and accelerating high brightness ion beams, called MEQALAC, has been developed at Brookhaven. The concept and its motivation will be described first, with reference to other sources for detail, and then the performance of two operating MEQALAC's will be presented.
Date: January 1, 1981
Creator: Gammel, G.; Brodowski, J.; Keane, J.; Maschke, A.; Meier, E.; Mobley, R. et al.
Partner: UNT Libraries Government Documents Department

Beam position monitoring in the AGS Linac to Booster transfer line

Description: A beam position monitor system has been developed and used in the commissioning of Brookhaven`s Linac to Booster transfer line. This line transports a chopped, RF modulated H- beam from the 200 MeV Linac to the AGS Booster. Over a 15dB dynamic range in beam current, the position monitor system provides a real-time, normalized position signal with an analog bandwidth of about 20 MHz. Seven directional coupler style pickups are installed in the line with each pickup sensing both horizontal and vertical position. Analog processing electronics are located in the tunnel and incorporate the amplitude modulation to phase modulation normalization technique. To avoid interference from the 200 MHz linac RF system, processing is performed at 400 MHz. This paper will provide a system overview and report results from the commissioning experience.
Date: December 31, 1991
Creator: Shea, T. J.; Brodowski, J. & Witkover, R.
Partner: UNT Libraries Government Documents Department

Rf systems for RHIC

Description: The RHIC rf systems must capture the injected beam, accelerate it through transition to top energy, shorten the bunches prior to rebucketing, and store the beam for 10 hours in the presence of strong intra-beam scattering. These different functions are met by three independent systems. An accelerating system at 26.7 Mhz (h = 342), a storage system at 196.1 MHz (h = 2508), and a wideband system for the damping of injection efforts.
Date: May 1, 1995
Creator: Rose, J.; Brodowski, J.; Connolly, R.; Deng, D.P.; Kwiatkowski, S.; Pirkl, W. et al.
Partner: UNT Libraries Government Documents Department

THERMO-MECHANICAL RESPONSE OF THE HALO INTERCEPTS INTERACTING WITH THE SNS PROTON BEAM.

Description: Integral part of the primary collimator of the SNS accumulator ring is a halo intercept assembly in the form of movable scraper blades that allow interception of the halo protons in four planes. In order to achieve large coulomb scattering of the halo protons and energy losses of less than 1%, platinum was chosen as the material of choice while its thickness was optimized to satisfy the energy loss requirements. This paper outlines the adopted design of the scraper assembly and presents the thermal response of the system that intercepts the beam halo as well as the subsequent thermal stress analysis and the issues associated with the performance of the scraper. Specifically, the current design incorporates a highly conducting material (copper) in the blade structure interfacing with the platinum scraper and is responsible for conducting the deposited energy away from the beam interception region. The mechanical performance and durability of such system, especially of the special bonding between the dissimilar materials, is the primary focus of this effort.
Date: June 18, 2001
Creator: SIMOS,N.; LUDEWIG,H.; CATALAN-LASHERAS,N.; BRODOWSKI,J. & WEI,J.
Partner: UNT Libraries Government Documents Department

Design of the 26.7 MHz rf cavity for RHIC

Description: The accelerating system for RHIC operates at 26.7 MHz (h = 342) and must capture the injected beam, accelerate it to top energy, and shorten the bunches prior to rebucketing into the storage (h = 2508) system. These different functions set the design parameters of the cavity. The frequency of 26.7 MHz has been chosen in order to provide large enough buckets to capture the injected beam from the AGS and a large linear region for debunching during a bunch rotation at top energy. Provision of the large linear region also dictates the voltage requirement of 400 kV per cavity. The cavity must be tuned {approximately}90 kHz to compensate for the change in speed of the gold beam.
Date: May 1, 1995
Creator: Rose, J.; Brodowski, J.; Deng, D.P.; Kwiatkowski, S.; Pirkl, W. & Ratti, A.
Partner: UNT Libraries Government Documents Department

A LARGE APERTURE NARROW QUADROUPOLE FOR THE SNS ACCUMULATOR RING.

Description: The accumulator ring of the Spallation Neutron Source (SNS) is designed to accept high-intensity H{sup -} beam of 1 GeV kinetic energy from the injecting LINAC, and to accumulate, in a time interval of 1 msec, 2 x 10{sup 14} protons in a single bunch of 700 nsec. In order to optimize the effective straight-section spaces for beam-injection, extraction and collimation, we have minimized the width of the large aperture quadrupoles which are located in the same straight sections of the accumulator ring with the injection and extraction systems. By minimizing the width of the quadrupoles to {+-}40.4 cm, the beam-injection and extraction angles are lowered to 8.75{sup o} and 16.8{sup o} respectively. Further optimization of the narrow quadrupole, minimizes the strength of the dodecapole multipole component of the quadrupole, thus reducing the width of the 12pole structure resonance and allowing a larger tune space for stability of the circulating beam. In this paper we present results derived from magnetic field calculations of 2D and 3D modeling, and discuss the method of optimizing the size of the quadrupole and minimizing its dodecapole multipole component.
Date: June 3, 2002
Creator: TSOUPAS,N.; BRODOWSKI,J.; MENG,W.; WEI,J.; LEE,Y.Y. & TUOZZOLO,J.
Partner: UNT Libraries Government Documents Department

HIGH LEVEL RF FOR THE SNS RING.

Description: A high level RF system (HLRF) consisting of power amplifiers (PA's) and ferrite loaded cavities is being designed and built by Brookhaven National Laboratory (BNL) for the Spallation Neutron Source (SNS) project. It is a fixed frequency, two harmonic system whose main function is to maintain a gap for the kicker rise time. Three cavities running at the fundamental harmonic (h=l) will provide 40 kV and one cavity at the second harmonic (h=2) will provide 20 kV. Each cavity has two gaps with a design voltage of 10 kV per gap and will be driven by a power amplifier (PA) directly adjacent to it. The PA uses a 600kW tetrode to provide the necessary drive current. The anode of the tetrode is magnetically coupled to the downstream cell of the cavity. Drive to the PA will be provided by a wide band, solid state amplifier located remotely. A dynamic tuning scheme will be implemented to help compensate for the effect of beam loading.
Date: June 3, 2002
Creator: ZALTSMAN,A.; BLASKIEWICZ,M.; BRENNAN,J.; BRODOWSKI,J.; METH,M.; SPITZ,R. et al.
Partner: UNT Libraries Government Documents Department

Status of the BNL 200 MeV Linac

Description: 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.
Date: January 1, 1986
Creator: McNerney, A.; Brennan, J.M.; Briscoe, B.; Brodowski, J.; Horton, R.; LoDestro, V. et al.
Partner: UNT Libraries Government Documents Department

MEQALAC: (multiple electrostatic quadrupole linac): a new approach to low beta rf acceleration

Description: MEQALAC is an acronym for a multiple-beam electrostatic-quadrupole array linear accelerator. The principle of operation is very simple. It makes use of the fact that electrostatic quadrupoles focus more effectively at low velocities than conventional magnetic quadrupoles. Moreover, the pole-tip field of an electrostatic quadrupole is limited by field emission of electrons, and is not a function of the size of the quadrupole. Conventional magnetic quadrupoles, on the other hand, require increasingly high current densities if one attempts to scale to smaller size.
Date: January 1, 1980
Creator: Mobley, R.M.; Brodowski, J.J.; Gammel, G.M.; Keane, J.T.; Maschka, A.W. & Sanders, R.T.
Partner: UNT Libraries Government Documents Department

RHIC stochastic cooling motion control

Description: Relativistic Heavy Ion Collider (RHIC) beams are subject to Intra-Beam Scattering (IBS) that causes an emittance growth in all three-phase space planes. The only way to increase integrated luminosity is to counteract IBS with cooling during RHIC stores. A stochastic cooling system for this purpose has been developed, it includes moveable pick-ups and kickers in the collider that require precise motion control mechanics, drives and controllers. Since these moving parts can limit the beam path aperture, accuracy and reliability is important. Servo, stepper, and DC motors are used to provide actuation solutions for position control. The choice of motion stage, drive motor type, and controls are based on needs defined by the variety of mechanical specifications, the unique performance requirements, and the special needs required for remote operations in an accelerator environment. In this report we will describe the remote motion control related beam line hardware, position transducers, rack electronics, and software developed for the RHIC stochastic cooling pick-ups and kickers.
Date: March 28, 2011
Creator: Gassner, D.; DeSanto, L.; Olsen, R.H.; Fu, W.; Brennan, J.M.; Liaw, CJ et al.
Partner: UNT Libraries Government Documents Department

DESIGN AND PERFORMANCE OF THE MATCHING BEAMLINE BETWEEN THE BNL EBIS AND AN RFQ.

Description: A part of a new EBIS-based heavy ion preinjector, the low energy beam transport (LEBT) section between the high current EBIS and the RFQ is a challenging design, because it must serve many functions. In addition to the requirement to provide an efficient matching between the EBIS and the RFQ, this line must serve as a fast ''switchyard'', allowing singly charged ions from external sources to be transported into the EBIS trap region, and extracted, highly charged ions to be deflected to off-axis diagnostics (time-of-flight or emittance). The space charge of the 5-10 mA extracted heavy ion beam is a major consideration in the design, and the space charge force varies for different ion beams having Q/m from 1-0.16. The line includes electrostatic lenses, spherical and parallel-plate deflectors, magnetic solenoid, and diagnostics for measuring current, charge state distributions, emittance, and profile. A prototype of this beamline has been built, and results of tests are presented.
Date: June 25, 2007
Creator: ALESSI,J.; BEEBE, E.; BRODOWSKI, J.; KPONOU, A.; OKAMURA, M.; PIKIN, A. et al.
Partner: UNT Libraries Government Documents Department