摘要:

Coherent phenomena and recent theoretical approaches to them are reviewed for the symmetric and asymmetrice+e−colliding storage rings.

ISSN:0094-243X    

DOI:10.1063/1.39771

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Performance limitations of electron‐positron circular colliders are reviewed with emphasis on examining beam‐beam limits through experimental data collected from operating storage rings. Particular emphasis has been put on reviewing scaling laws for the beam‐beam parameter, or ‘‘tune‐shift.’’Observational data on colliders with asymmetric energy are not readily available. Several measurements of the dependence of luminosity and beam‐beam parameter on operating energy are presented to stimulate interest in further experiments.

ISSN:0094-243X    

DOI:10.1063/1.39792

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

With the design of an RF system suitable for a storage ring B factory in mind this article points out the character and limitations of existing technology applicable to the design of a B factory. Furthermore, in view of these limitations the authors conclude that single cell cavities are a logical alternative to the multicell structures common to operating storage rings. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.39773

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Electronic feedback systems which actively damp longitudinal and transvere coherent coupled bunch instabilities are reviewed. Such feedback systems are essential to ensure stability of the high circulating currents required for B‐factories.

ISSN:0094-243X    

DOI:10.1063/1.39774

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A systematic comparison of accelerator physics issues from the beam‐beam interaction to single particle stability including ring and IR layout, synchrotron radiation and lost particle backgrounds, and single and multi‐bunch instabilities is given. While some practical handicap probably accrues to the asymmetric design because of its extra constraints, the differences in the two approaches tend to be obscured by larger issues such as how to achieve the enormous increases in luminosity demanded of a b‐factory.

ISSN:0094-243X    

DOI:10.1063/1.39776

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Beam‐beam simulations that incorporate the phenomenon of phase‐averaging are used to compare and contrast the dynamics of flat and round beams. Flat beams are found to require short bunches, and give a tune‐shift limit of around 0.05. Round beams allow bunch‐lengths of the order &bgr;*, and yield tune‐shifts of 0.10 or more.

ISSN:0094-243X    

DOI:10.1063/1.39777

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

‘‘The present situation of the B factory studies is that the problems of the synchrotron radiation background in the detector appear almost insurmountable for head‐on collisions with round beams. This paper explores the possibility of colliding flat beams in the head‐on cofiguration and evaluates the synchrotron radiation background. All of the formulae derived in this paper would indicate that this flat beam shape should lead to a significant improvement in the detector environment.’’ (AIP)

ISSN:0094-243X    

DOI:10.1063/1.39778

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The paper compares of the ultimate luminosities which can be achieved for an asymmetric B‐factory (4*7 GeV) in cases of the flat and round beams.

ISSN:0094-243X    

DOI:10.1063/1.39779

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Simulations suggest that ine+e−storage rings collisions of round beams (equal emittances and equal &bgr;*) can produce very large tune shifts and luminosities. We understand how to make equal &bgr;*s, but generating equal emittances is more difficult. We describe an equal emittance scheme that uses several skew quads to couple horizontal dispersion into vertical dispersion. These skew quads also produce a coupling bump. At the interaction point and at other points outside the coupling bump, the motion is not coupled, so that the ‘A’ normal mode corresponds to horizontal motion and the ‘B’ normal mode corresponds to vertical motion. We present a round beam lattice for CESR that incorporates this scheme.

ISSN:0094-243X    

DOI:10.1063/1.39780

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The CERN‐PSI feasibility study of a B‐Meson Factory in the ISR tunnel has resulted in the proposal of a 3.5 on 8.0 GeV machine with a bunch spacing of 12 m, to be reduced eventually to 3 m. The beams will be vertically separated by the radial field component of the 1.5 T experimental solenoids, rotated for this purpose by 4 degrees, and by the fields acting on the off‐centered beams in the central interaction region quadrupoles. Vertical separations of 6 &sgr;xare obtained at 3 m from IP, and of 2.5 &sgr;xat 1.5 m. The solenoid tilt and the amount of synchrotron radiation arriving in the central detector are compatible with the requirements of the experiments. The geometry and the performance of the proposed separation scheme are presented.

ISSN:0094-243X    

DOI:10.1063/1.39766

出版商:AIP    

年代:1990

数据来源: AIP