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Title: Optical Effects of Wakefields in the PEP-II Stanford Linear Accelerator Center B Factory

Abstract

Wakefields defining beam stability affect also the beam optics and beam properties in high current machines. In this paper we present observations and analysis of the optical effects in the PEP-II SLAC B-factory, which has the record in achievement of high electron and positron currents. We study the synchronous phase and the bunch length variation along the train of bunches, overall bunch lengthening and effects of the wakes on the tune and on the Twiss parameters. This analysis is being used in upgrades of PEP-II and may be applied to future B-factories and damping rings for Linear Colliders.

Authors:
; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
898878
Report Number(s):
SLAC-PUB-12319
TRN: US0701723
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys.Rev.ST Accel.Beams 10:011001,2007
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BEAM OPTICS; DAMPING; ELECTRONS; LINEAR COLLIDERS; POSITRONS; STABILITY; STANFORD LINEAR ACCELERATOR CENTER; Accelerators,ACCPHY

Citation Formats

Heifets, S., Novokhatski, S., Teytelman, D., and /SLAC. Optical Effects of Wakefields in the PEP-II Stanford Linear Accelerator Center B Factory. United States: N. p., 2007. Web. doi:10.1103/PhysRevSTAB.10.011001.
Heifets, S., Novokhatski, S., Teytelman, D., & /SLAC. Optical Effects of Wakefields in the PEP-II Stanford Linear Accelerator Center B Factory. United States. doi:10.1103/PhysRevSTAB.10.011001.
Heifets, S., Novokhatski, S., Teytelman, D., and /SLAC. Mon . "Optical Effects of Wakefields in the PEP-II Stanford Linear Accelerator Center B Factory". United States. doi:10.1103/PhysRevSTAB.10.011001. https://www.osti.gov/servlets/purl/898878.
@article{osti_898878,
title = {Optical Effects of Wakefields in the PEP-II Stanford Linear Accelerator Center B Factory},
author = {Heifets, S. and Novokhatski, S. and Teytelman, D. and /SLAC},
abstractNote = {Wakefields defining beam stability affect also the beam optics and beam properties in high current machines. In this paper we present observations and analysis of the optical effects in the PEP-II SLAC B-factory, which has the record in achievement of high electron and positron currents. We study the synchronous phase and the bunch length variation along the train of bunches, overall bunch lengthening and effects of the wakes on the tune and on the Twiss parameters. This analysis is being used in upgrades of PEP-II and may be applied to future B-factories and damping rings for Linear Colliders.},
doi = {10.1103/PhysRevSTAB.10.011001},
journal = {Phys.Rev.ST Accel.Beams 10:011001,2007},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 29 00:00:00 EST 2007},
month = {Mon Jan 29 00:00:00 EST 2007}
}
  • Recent precise results from several experiments have confirmed the early evidence that the lifetime of hadrons containing B-quarks is rather long, implying that the third generation of quarks is more decoupled from the first two than the second is from the first. The average of the measurements performed by the experiments at PEP is 1.08 +- 0.13 ps.
  • The radiation safety system (RSS) of the B-Factory accelerator facility at the Stanford Linear Accelerator Center (SLAC) is described. The RSS, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system (ACS) and the radiation containment system (RCS). The ACS prevents people from being exposed to the very high radiation levels inside a beamline shielding housing. The ACS consists of barriers, a standard entry module at every entrance, and beam stoppers. The RCS prevents people from being exposed to the radiation outside a shielding housing, due to either normal ormore » abnormal operation. The RCS consists of power limiting devices, shielding, dump/collimator, and an active radiation monitor system. The inter-related system elements for the ACS and RCS, as well as the associated interlock network, are described. The policies and practices in setting up the RSS are also compared with the regulatory requirements.« less
  • The radiation safety system (RSS) of the B-Factory accelerator facility at the Stanford Linear Accelerator Center (SLAC) is described. The RSS, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system (ACS) and the radiation containment system (RCS). The ACS prevents people from being exposed to the very high radiation levels inside a beamline shielding housing. The ACS consists of barriers, a standard entry module at every entrance, and beam stoppers. The RCS prevents people from being exposed to the radiation outside a shielding housing, due to either normal ormore » abnormal operation. The RCS consists of power limiting devices, shielding, dump/collimator, and an active radiation monitor system. The inter-related system elements for the ACS and RCS, as well as the associated interlock network, are described. The policies and practices in setting up the RSS are also compared with the regulatory requirements.« less
  • The testing of the upgrade prototype for the bunch current monitors (BCMs) in the PEP-II storage rings at the Stanford Linear Accelerator Center (SLAC) is the topic of this paper. Bunch current monitors are used to measure the charge in the electron/positron bunches traveling in particle storage rings. The BCMs in the PEP-II storage rings need to be upgraded because components of the current system have failed and are known to be failure prone with age, and several of the integrated chips are no longer produced making repairs difficult if not impossible. The main upgrade is replacing twelve old (1995)more » field programmable gate arrays (FPGAs) with a single Virtex II FPGA. The prototype was tested using computer synthesis tools, a commercial signal generator, and a fast pulse generator.« less
  • PEP II is being built as a higher luminosity electron--positron collider with asymmetric beams of 9 and 3.1 GeV, having maximum currents of 3.0 A. Based on our previous work on the National Synchrotron Light Source (NSLS) vacuum ultraviolet beamline U10B, a copper was selected for construction of ultrahigh vacuum beam chambers and absorbers to minimize the pressure rise from synchrotron radiation during operation. An extruded beam chamber and a welded beam chamber were fabricated from the selected copper for photon stimulated desorption measurements on the NSLS x-ray beamline X28A. The chambers were exposed to white light with a criticalmore » energy of 5 keV, both directly and through a 0.010-in.-thick beryllium filter. Each chamber was exposed to a dose of approximately 10{sup 23} photons per meter at an incidence angle of 25 mrad, after argon glow preconditioning and a 150 {degree}C vacuum bake. Desorption yields for H{sub 2} CO, CO{sub 2}, and CH{sub 4} are reported as a function of accumulated photon flux, critical energy, and chamber preparation. The results are compared with the previous work on the beamline U10B and with those of other published work on copper. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}« less