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Title: Beam-beam dynamics during the injection process at the PEP-II B-Factory

Abstract

This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory based on PEP (PEP-2). For symmetric colliders, the primary source of the beam-beam effect is the head-on collision at the interaction point (IP), and this effect can be mitigated by separating the beams during the injection process. For an asymmetric collider, which intrinsically consists of two separate rings, the bunches not only collide at the IP but experience a long-range beam-beam force on the way into and out of the IP region. These collisions are called parasitic crossings (PC).'' The parasitic crossings emerge as a potential source of far stronger beam-beam impact during the injection process for the following reason. In the proposed injection scheme of the APIARY-6.3d design, the bunches are injected horizontally into the two rings with large horizontal offset of 8{sigma}{sub Ox}{sup sptm} where {sigma}{sub Ox}{sup sptm} is the nominal horizontal storage ring beam size at the end of the septum magnet. Then, the injected beam starts to travel around the ring oscillating horizontally. For the sake of discussion, let us assume that the beam in the other ring has already been fully stored. When the injected beam arrives atmore » the 1st PC, where the two nominal orbits are separated horizontally by about 7.6 times the nominal horizontal beam size of the low energy ring, it may pass through the other beam far more closely than at the nominal separation distance, or it may even strike the other beam head-on.« less

Authors:
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
6100214
Report Number(s):
LBL-31434
ON: DE92004097
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; PEP STORAGE RINGS; BEAM-BEAM INTERACTIONS; BEAM BUNCHING; BEAM INJECTION; COLLIDING BEAMS; PHASE SPACE; BEAM DYNAMICS; BEAMS; MATHEMATICAL SPACE; SPACE; STORAGE RINGS; 430400* - Particle Accelerators- Storage Rings; 430200 - Particle Accelerators- Beam Dynamics, Field Calculations, & Ion Optics

Citation Formats

Chin, Yong Ho. Beam-beam dynamics during the injection process at the PEP-II B-Factory. United States: N. p., 1991. Web. doi:10.2172/6100214.
Chin, Yong Ho. Beam-beam dynamics during the injection process at the PEP-II B-Factory. United States. https://doi.org/10.2172/6100214
Chin, Yong Ho. 1991. "Beam-beam dynamics during the injection process at the PEP-II B-Factory". United States. https://doi.org/10.2172/6100214. https://www.osti.gov/servlets/purl/6100214.
@article{osti_6100214,
title = {Beam-beam dynamics during the injection process at the PEP-II B-Factory},
author = {Chin, Yong Ho},
abstractNote = {This paper is concerned with beam-beam effects during the injection process at the proposed asymmetric SLAC/LBL/LLNL B-Factory based on PEP (PEP-2). For symmetric colliders, the primary source of the beam-beam effect is the head-on collision at the interaction point (IP), and this effect can be mitigated by separating the beams during the injection process. For an asymmetric collider, which intrinsically consists of two separate rings, the bunches not only collide at the IP but experience a long-range beam-beam force on the way into and out of the IP region. These collisions are called parasitic crossings (PC).'' The parasitic crossings emerge as a potential source of far stronger beam-beam impact during the injection process for the following reason. In the proposed injection scheme of the APIARY-6.3d design, the bunches are injected horizontally into the two rings with large horizontal offset of 8{sigma}{sub Ox}{sup sptm} where {sigma}{sub Ox}{sup sptm} is the nominal horizontal storage ring beam size at the end of the septum magnet. Then, the injected beam starts to travel around the ring oscillating horizontally. For the sake of discussion, let us assume that the beam in the other ring has already been fully stored. When the injected beam arrives at the 1st PC, where the two nominal orbits are separated horizontally by about 7.6 times the nominal horizontal beam size of the low energy ring, it may pass through the other beam far more closely than at the nominal separation distance, or it may even strike the other beam head-on.},
doi = {10.2172/6100214},
url = {https://www.osti.gov/biblio/6100214}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 01 00:00:00 EDT 1991},
month = {Tue Oct 01 00:00:00 EDT 1991}
}