摘要:

Upgrades to the Brookhaven AGS are described. The AGS Booster which delivers proton beams of 1.5–1.9 GeV and the 200 MeV linac facilities are described. Space charge and beam emittance characteristics are discussed. (AIP) ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56785

出版商:AIP    

年代:1998

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.56767

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5 &mgr;s with average beam power of 1MW. To achieve such purpose, a proton storage ring operated at 60Hz with1×1014protons per pulse at 1GeV is required. The Accumulator Ring (AR) receives 1msec longH−beam bunches of 28mA from a 1GeV linac. Scope and design performance goals of the AR are presented. About 1200 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. will be discussed. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56768

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The longitudinal space-charge force in neutron spallation source compressor ring or other high intensity proton storage rings can be compensated by introducing an insert in the ring. The effect of the inductor is to cancel all or part of the space charge potential, because it is capacitive. The Proton Storage Ring at Los Alamos National Laboratory is a compressor ring used to produce short pulses of spallation neutrons. Inductive inserts design for space charge compensation at the Los Alamos Proton Storage Ring is described. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56770

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Some issues are presented on the rf system in the future Fermilab pre-booster, which accelerates 4 bunches each containing0.25×1014&hthinsp;protonsfrom 1 to 3 GeV kinetic energy. The problem of beam loading is discussed. The proposal of having a non-tunable fixed-frequency rf system is investigated. Robinson’s criteria for phase stability are checked and possible Robinson instability growth is computed. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56771

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We review experimental observations of space-charge effects and collective phenomena in charged particle beams for accelerator applications. These include halo formation and emittance growth, bunch profile evolution, space-charge waves, and longitudinal instabilities. We also report on the development of the University of Maryland Electron Ring for the study of space-charge physics in a circular lattice. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56772

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

For high intensity proton runs, emittance blow-up is often accompanied with nontrivial beam loss. It has been suggested [10] that the largest portion of the Booster to AGS (BTA) transfer loss is located in the AGS end. It was also found that the space charge tune spread, immediately after the bunched beam enters the AGS ring, is large enough for the envelope resonance and emittance blow-up [11]. It was decided, in 1997 high intensity proton run, to raise the BTA transfer kinetic energy from 1.54 GeV to 1.9 GeV. The transfer efficiency was increased, as expected. The beam emittance in the AGS ring did not increase, even the AGS acceptance was enlarged [12], which is probably because of the reduced space charge tune spread. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56773

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

An exactly solvable model of transverse stability in bunched beams is presented. The model assumes a square well longitudinal potential with a hollow longitudinal phase space distribution. The effects of space charge in conjunction with both short and long range wake fields as well as damping systems are investigated. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56774

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We review the derivation of moment equations which include the effects of space charge and dispersion in bends first presented in ref. [1]. These equations generalize the familiar envelope equations to include the dispersive effects of bends. We review the application of these equations to the calculation of the change in emittance resulting from a sharp transition from a straight section to a bend section, using an energy conservation constraint. Comparisons of detailed 2D and 3D simulations of intense beams in rings using the WARP code (refs. [2,3]) are made with results obtained from the moment equations. We also compare the analysis carried out in ref. [1], to more recent analyses, refs. [4,5]. We further examine self-consistent distributions of beams in bends and discuss the relevance of these distributions to the moment equation formulation. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56775

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A micromap approach to space charge is presented as a concept easily implemented in a computer code. A map of arbitrary length is found to be a suitable tool to include space charge by means of a kick approximation. We adopt space charge description where a transverse elliptic particle symmetry is assumed, and all analysis is carried out in a coasting beam approximation. This approach is particularly useful to investigate the single particle dynamics when the working point of a machine lies in a resonance driven by a skew quadrupole. Since the improvement of the multiturn injection efficiency due to linear coupling is based mainly on the exchange of emittance between x- and y-planes, we have investigated the emittance exchange dynamics when space charge is not negligible. We found that a coherent effect of space charge improves the efficiency of the exchange with respect to the case of single particle emittance exchange with space charge neglected. ©1998 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.56776

出版商:AIP    

年代:1998

数据来源: AIP