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Space charge effects: tune shifts and resonances

Description: The effects of space charge and beam-beam interactions on single particle motion in the transverse degree of freedom are considered. The space charge force and the resulting incoherent tune shift are described, and examples are given from the AGS and CERN's PSB. Equations of motion are given for resonances in the presence of the space charge force, and particle behavior is examined under resonance and space charge conditions. Resonance phase space structure is described with and without space charge. Uniform and bunched beams are compared. Beam-beam forces and resonances and beam-beam detuning are described. 18 refs., 15 figs. (LEW)
Date: August 1, 1986
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Forces on the conductors of the Arc AG Magnet

Description: In the evaluation of the design of the support system for the Arc AG Magnets, factors which could deform or move the magnet have to be considered. Typically they are the ground movements, temperature effects, water vibrations, magnetic forces on the magnet and coil, and accidental human or equipment impacts. This note calculates the magnetic forces on the conductors at an excitation for a 50 GeV beam. It is found that the force is not negligible; therefore, a method to restrict the movement of the conductors should be introduced.
Date: December 28, 1983
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Fundamentals: Longitudinal motion

Description: This paper discusses the following topics on synchrotrons: Dynamics of Synchrotron; Acceleration Cavity; Beam Manipulation and Beam Control; and High Intensity Effects. 21 refs., 26 figs. (LSP)
Date: November 7, 1988
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

New AGS fast extraction system

Description: Both the high energy physics program and ISA injection require an improved fast extraction system from the AGS. The proposed new system consists of a fast kicker at H5 and an ejector magnet at H10. The H5 kicker is capable of producing 1.2 mrad deflection and rising up to 99% strength in 150 nsec with flat top ripple within +- 1%. It is found that the focusing strengths and positions of UQ3-UQ7 have to be modified to achieve an achromatic condition at the end of 8/sup 0/-bend. Also, the conceptual design of the H5 magnet and the pulser system are discussed.
Date: September 1, 1980
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

AGS new fast extraction system and the single bunch extraction test

Description: For the neutrino physics program and for the CBA injection, a new fast extraction system has been implemented to improve the extraction efficiency and the quality of the extracted beam. Central to the new system is a new fast kicker, placed at the H5 straight section, capable of rising between bunches, t/sub r/ < 170 nsec, and staying constant for 2.6 ..mu..sec with flat top ripple less than +-1.5%. So far, the system has been operated for longer than 3000 hours and routinely extracts 10/sup 13/ ppp at 99% efficiency. Experiment 745 on QCD test requires a single AGS bunch of 40 nsec. For this purpose another fast kicker was placed at the E5 straight section and powered by a new pulser to produce a half sinusoidal pulse with both a rise and fall time of 200 nsec. A single AGS bunch was extracted through the slow beam channel at 22 GeV/c leaving the remaining 11 bunches undisturbed which continued to be accelerated to 29.4 GeV/c and extracted by the H5 kicker through the fast beam channel. Because the ring circumference ratio of CBA to the AGS is 4-3/4, some of the injected beam from the AGS has to contain 11 bunches instead of 12; consequently, this single bunch extraction mode will also be used for CBA injection.
Date: January 1, 1983
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Lattice design and tolerance analysis of the CBA transport line

Description: The beam transport line from the AGS to CBA is 600 m long and consists of 70 bending magnets and 20 quadrupoles, as well as several special injection components. The beam has to bend 117/sup 0/ horizontally and drop 1.8 m in elevation. To insure that it has momentum acceptance of ..delta..P/P = +-1% and the transverse emittance dilution is within 30%, a detailed tolerance analysis has been carried out on the requirements of the AGS beam properties, magnetic field quality of the transport magnets, and misalignment errors. Field quality tolerances of ..delta..B/sub 0//B less than or equal to 1 x 10/sup -3/ for bending field, ..delta.. G/G less than or equal to 5 x 10/sup -3/ for gradient field, and ..delta..B/sub 2//B less than or equal to 2.5 x 10/sup -4/ cm/sup -2/ of the sextupole components in the bending magnets are indicated.
Date: January 1, 1983
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Introduction to the magnet and vacuum systems of an electron storage ring

Description: An accelerator or storage ring complex is a concerted interplay of various functional systems. For the convenience of discussion we can divide it into the following systems: injector, magnet, RF, vacuum, instrumentation and control. In addition, the conventional construction of the building and radiation safety consideration are also needed and finally the beam lines, detector, data acquisition and analysis set-ups for research programs. Dr. L. Teng has given a comprehensive review of the whole complex and the operation of such a facility. I concentrate on the description of magnet and vacuum systems. Only the general function of each system and the basic design concepts will be introduced, no detailed engineering practice will be given which will be best done after a machine design is produced. For further understanding and references a table of bibliography is provided at the end of the paper.
Date: August 15, 1982
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Progress with the AGS Booster

Description: Rare K-decay, neutrino and heavy ion physics demands that a rapid- cycling high vacuum and high intensity Booster be built for the AGS at Brookhaven. For each mode of operation there are corresponding accelerator physics and design issues needing special attention. Problems pertinent to any single mode of operation have been encountered and solved before, but putting high intensity proton requirements and high vacuum heavy ion requirements into one machine demands careful design considerations and decisions. The lattice design and magnet characteristics will be briefly reviewed. Major design issues will be discussed and design choices explained. Finally, the construction status and schedule will be presented. 6 refs., 6 figs.
Date: January 1, 1988
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Analysis of optical perturbations of the SLC arcs

Description: This paper establishes the analytical framework in solving optical pertubations in a transport line in general and the SLC Arc specifically. The Formulation presented here is applicable to any transport system in a straightforward way. The equations of motion of a perturbed betatron function and dispersion function are presented. Sources of field errors for the SLC Arc system are discussed. Magnitudes of pertubations to the optical functions for the SLC Arc are estimated. (JDH)
Date: January 1, 1987
Creator: Weng, W.T. & Sands, M.
Partner: UNT Libraries Government Documents Department

Hadron-hadron colliders

Description: The objective is to investigate whether existing technology might be extrapolated to provide the conceptual framework for a major hadron-hadron collider facility for high energy physics experimentation for the remainder of this century. One contribution to this large effort is to formalize the methods and mathematical tools necessary. In this report, the main purpose is to introduce the student to basic design procedures. From these follow the fundamental characteristics of the facility: its performance capability, its size, and the nature and operating requirements on the accelerator components, and with this knowledge, we can determine the technology and resources needed to build the new facility.
Date: June 21, 1983
Creator: Month, M. & Weng, W.T.
Partner: UNT Libraries Government Documents Department

Resonance behavior in the presence of space charge

Description: An analysis is presented of the resonance behavior of particle beams in the presence of space charge fields. Since self-consistent requirements are ignored, the results describe onset or early behavior. It is shown that in a beam of uniform current resonances excited by magnetic field errors are stabilized by the detuning effect of the self-field space charge force. This situation is changed when a radiofrequency accelerating field is applied. As beam bunching results after rf turn-on, the space charge force becomes modulated along the bunches, vanishing at the ends. At these regions of small or vanishing space charge, stabilization from non-linear detuning tends to disappear, thus leaving particles susceptible to resonance blow-up. This picture of the effect of beam bunching can be studied by considering the phase space structure for particles at different positions along the bunches. A somewhat unusual conclusion is made on the use of this analysis to model beam capture in a synchrotron at low energy.
Date: January 1, 1983
Creator: Month, M. & Weng, W.T.
Partner: UNT Libraries Government Documents Department

Nomenclature of SLC Arc beamline components

Description: This note defines I and C formal names for beamline components in the Arc as specified in the TRANSPORT decks ARCN FINAL and ARCS FINAL of June 5, 1985. The formal name consists of three fields: the primary name, the zone and the unit number. The general principles and guidelines are explained in Reference 1. The rationale and the final resolutions of the naming conventions for the Arc are explained.
Date: April 10, 1986
Creator: Silva, J. & Weng, W.T.
Partner: UNT Libraries Government Documents Department

Performance and measurements of the AGS and Booster beams

Description: Analyses of Hot Gas Stream Cleanup (HGSC) ashes and descriptions of filter performance were made to address the problems with filter operation that are apparently linked to the collected ash. This task is designed to generate data base of the key properties of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters. Activities including initial formatting of the data base and entry, modification of the permeability model, and initial design of a high-temperature test device for measuring uncompacted bulk porosity of ash aggregates (indicator of relative cohesivity of the ash, filter cake porosity/permeability). Chemical analyses of hopper and filter cake ashes from Tidd showed that the consolidation degree could not be accounted for by condensation/adsorption from the flue gas; the mechanism is likely physical rearrangement of the ash particles.
Date: December 31, 1995
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

Coupled vibrational modes of the SLC Arc magnet and support system

Description: The magnet support system for the SLC Arcs will be a long series of pedestals with each pedestal supporting the ends of two adjacent magnets. It has been pointed out by several authors that random magnet vibrations in the Arc with amplitudes larger than 0.1 ..mu..m rms are potentially harmful for the SLC operation. In order to assess the vibrational behavior of the Arc magnet system, we need to understand: (1) the sources and characteristics of the ground disturbances, (2) the coupled vibrational modes of the composite pedestal-magnet system, and (3) the response of the system to ground disturbance. This note is an attempt to study item (2). 5 refs., 4 figs., 1 tab.
Date: March 1, 1985
Creator: Weng, W.T. & Chao, A.W.
Partner: UNT Libraries Government Documents Department

Vibrational modes of the pedestal support system for the SLC Arc magnets

Description: The magnet support system for the SLC Arcs will be a long series of pedestals with each pedestal supporting the ends of two adjacent magnets. It has been pointed out by several authors that random magnet vibrations in the Arc with amplitudes larger than 0.1 ..mu..m rms are potentially harmful for the SLC operation. In order to assess the vibrational behavior of the Arc magnet system, we need to understand: (1) the sources and characteristics of the ground disturbances, (2) the coupled vibrational modes of the composite pedestal-magnet system and, (3) the response of the system to ground disturbance.
Date: October 1, 1984
Creator: Weng, W.T. & Chao, A.W.
Partner: UNT Libraries Government Documents Department

Analysis of orbit perturbations of the SLC arcs

Description: The generation and correction of orbit errors are analyzed. A general stability criterion for the orbit correction is established and the rms orbit errors and corrector strengths are calculated. The formulation is then applied to the design of the Stanford Linear Collider to obtain estimates for residual orbit distortion after correction. (LEW)
Date: January 1, 1987
Creator: Weng, W.T.; Murray, J. & Chao, A.
Partner: UNT Libraries Government Documents Department

Operation of the Brookhaven AGS with the Booster

Description: The Brookhaven Alternating Gradient Synchrotron (AGS) received protons directly from a Linac and heavy ions directly from a Tandem Van de Graaff before 1992. The newly constructed Booster has been brought on line to serve as an injector for the AGS. The operational status of the acceleration of proton and heavy ions through the Booster and the AGS is reviewed. Accelerator improvement programs to increase proton intensity for physics research and to prepare heavy ion beams for RHIC injection are discussed.
Date: June 1, 1993
Creator: Weng, W. T.
Partner: UNT Libraries Government Documents Department

COMPARATIVE STUDIES OF PROTON ACCELERATORS FOR HIGH POWER APPLICATIONS.

Description: There are many applications requiring high power proton accelerators of various kinds. However, each type of proton accelerator can only provide beam with certain characteristics, hence the match of accelerators and their applications need careful evaluation. In this talk, the beam parameters and performance limitations of linac, cyclotron, synchrotron, and FFAG accelerators are studied and their relative merits for application in neutron, muon, neutrino, and ADS will be assessed in terms of beam energy, intensity, bunch length, repetition rate, and beam power requirements. A possible match between the applications and the accelerator of choice is presented in a matrix form. The accelerator physics and technology issues and challenges involved will also be discussed.
Date: May 29, 2006
Creator: WENG, W.T.
Partner: UNT Libraries Government Documents Department

Ultra-High Intensity Proton Accelerators and their Applications

Description: The science and technology of proton accelerators have progressed considerably in the past three decades. Three to four orders of magnitude increase in both peak intensity and average flux have made it possible to construct high intensity proton accelerators for modern applications, such as: spallation neutron sources, kaon factory, accelerator production of tritium, energy amplifier and muon collider drivers. The accelerator design focus switched over from intensity for synchrotrons, to brightness for colliders to halos for spallation sources. An overview of this tremendous progress in both accelerator science and technology is presented, with special emphasis on the new challenges of accelerator physics issues such as: H(-) injection, halo formation and reduction of losses.
Date: December 31, 1997
Creator: Weng, W. T.
Partner: UNT Libraries Government Documents Department

Performances of BNL high-intensity synchrotrons

Description: The AGS proton synchrotron was completed in 1960 with initial intensity in the 10 to the 10th power proton per pulse (ppp) range. Over the years, through many upgrades and improvements, the AGS now reached an intensity record of 6.3 {times} 10{sup 13} ppp, the highest world intensity record for a proton synchrotron on a single pulse basis. At the same time, the Booster reached 2.2 {times} 10{sup 13} ppp surpassing the design goal of 1.5 {times} 10{sup 13} ppp due to the introduction of second harmonic cavity during injection. The intensity limitation caused by space charge tune spread and its relationship to injection energy at 50 MeV, 200 MeV, and 1,500 MeV will be presented as well as many critical accelerator manipulations. BNL currently participates in the design of an accumulator ring for the SNS project at Oak Ridge. The status on the issues of halo formation, beam losses and collimation are also presented.
Date: March 1, 1998
Creator: Weng, W.T.
Partner: UNT Libraries Government Documents Department

SNS accumulator ring design and space charge considerations

Description: The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5 {micro}s with average beam power of 1 MW. To achieve such purpose, a proton storage ring operated at 60 Hz with 1 {times} 10{sup 14} protons per pulse at 1 GeV is required. The Accumulator Ring (AR) receives 1 msec long H{sup {minus}} beam bunches of 28 mA from a 1 GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1 mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generatino and beam collimation etc. is discussed.
Date: August 1, 1998
Creator: Weng, W. T.
Partner: UNT Libraries Government Documents Department

SNS ACCUMULATOR RING DESIGN AND SPACE CHARGE CONSIDERATIONS

Description: The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5{micro}s with average beam power of 1MW. To achieve such purpose, a proton storage ring operated at 60Hz with 1 x 10{sup 14} protons per pulse at 1GeV is required. The Accumulator Ring (AR) receives 1msec long H{sup {minus}} beam bunches of 28mA from a 1GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generation and beam collimation etc. is discussed.
Date: May 4, 1998
Creator: WENG,W.T.
Partner: UNT Libraries Government Documents Department