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Title: Study of collective effects for the APIARY collider

Conference ·
OSTI ID:7248038

The design of a high-luminosity electron-positron collider to study B-physics is a challenging task from many points of view. In this paper we consider the influence of collective effects on the machine performance; most of our findings are generic,'' in the sense that they depend rather weakly on the details of the machine design. Based upon an example machine design (APIARY-II), we investigate single-bunch thresholds for the longitudinal microwave and transverse mode-coupling instabilities, examine the possibility of emittance growth from intrabeam scattering, calculate the beam lifetime from Touschek scattering and gas scattering, and estimate the growth rates for both longitudinal and transverse coupled-bunch instabilities. We find that the single-bunch instabilities should not lead to difficulty, and that the emittance growth is essentially negligible. At a background gas pressure of 10 nTorr, beam lifetimes of only a few hours are expected, which will place a burden on the injection system if a high average luminosity is to be maintained. Even this lifetime is likely to require an innovative design for the vacuum system to maintain a pressure of 10 nTorr in the presence of a circulating electron or positron beam of approximately 1 A. With a standard PEP-like multicell rf system, multibunch growth rates are very severe, especially in the longitudinal plane. There appear to be significant benefits to a radically different rf system design, either utilizing superconducting single-cell rf cavities, or cavities with equivalent geometrical shapes but operated at room temperature. Even then, a powerful feedback system will likely be required. Nonetheless, it does not appear that there are any fundamental problems that stand in the way of successfully designing and building such a high-luminosity B-Factory. 13 refs., 9 figs., 5 tabs.

Research Organization:
Lawrence Berkeley Lab., CA (USA)
Sponsoring Organization:
DOE/ER
DOE Contract Number:
AC03-76SF00098
OSTI ID:
7248038
Report Number(s):
LBL-27676; CONF-8906210-5; ON: DE90008493; TRN: 90-007975
Resource Relation:
Conference: Workshop on B-factories and related physics issues, Blois (France), 26 Jun - 1 Jul 1989
Country of Publication:
United States
Language:
English