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Title: Simulation of PEP-II Accelerator Backgrounds Using TURTLE

Abstract

We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using LPTURTLE, a modified version of the DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full program of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modeling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
876454
Report Number(s):
SLAC-PUB-11691
TRN: US200606%%663
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: Prepared for Particle Accelerator Conference (PAC 05), Knoxville, Tennessee, 16-20 May 2005
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; APERTURES; BETATRONS; COULOMB SCATTERING; DECAY; LUMINOSITY; OPTIMIZATION; RADIATIONS; SIMULATION; STANFORD LINEAR ACCELERATOR CENTER; Accelerators,ACCPHY

Citation Formats

Barlow, R.J., Fieguth, T., /SLAC, Kozanecki, W., /DSM, DAPNIA, Saclay, Majewski, S.A., /Stanford U., Phys. Dept., Roudeau, P., Stocchi, A., and /Orsay, LAL. Simulation of PEP-II Accelerator Backgrounds Using TURTLE. United States: N. p., 2006. Web.
Barlow, R.J., Fieguth, T., /SLAC, Kozanecki, W., /DSM, DAPNIA, Saclay, Majewski, S.A., /Stanford U., Phys. Dept., Roudeau, P., Stocchi, A., & /Orsay, LAL. Simulation of PEP-II Accelerator Backgrounds Using TURTLE. United States.
Barlow, R.J., Fieguth, T., /SLAC, Kozanecki, W., /DSM, DAPNIA, Saclay, Majewski, S.A., /Stanford U., Phys. Dept., Roudeau, P., Stocchi, A., and /Orsay, LAL. Wed . "Simulation of PEP-II Accelerator Backgrounds Using TURTLE". United States. doi:. https://www.osti.gov/servlets/purl/876454.
@article{osti_876454,
title = {Simulation of PEP-II Accelerator Backgrounds Using TURTLE},
author = {Barlow, R.J. and Fieguth, T. and /SLAC and Kozanecki, W. and /DSM, DAPNIA, Saclay and Majewski, S.A. and /Stanford U., Phys. Dept. and Roudeau, P. and Stocchi, A. and /Orsay, LAL},
abstractNote = {We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using LPTURTLE, a modified version of the DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full program of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modeling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 15 00:00:00 EST 2006},
month = {Wed Feb 15 00:00:00 EST 2006}
}

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  • To improve the understanding of accelerator-induced backgrounds at the SLAC B-Factory, we simulate lost particle backgrounds in the BABAR detector originating from beam-gas interactions and radiative Bhabha scatters. We have extended the GEANT4-based BABAR detector simulation to include beam-line components and magnetic fields up to 8.5 m away from the interaction point. We describe the simulation model and then compare preliminary predicted background levels with measurements from dedicated single- and colliding-beam experiments.
  • Background studies during the design, construction, commissioning, operation and improvement of BaBar and PEP-II have been greatly influenced by results from a program referred to as LPTURTLE (Lost Particle TURTLE) which was originally conceived for the purpose of studying gas background for SLC. This venerable program is still in use today. We describe its use, capabilities and improvements and refer to current results now being applied to BaBar.
  • The authors present a technique for the design and verification of efficient bunch-by-bunch controllers for damping longitudinal multibunch instabilities. The controllers attempt to optimize the use of available feedback amplifier power--one of the most expensive components of a feedback system--and define the limits of closed loop system performance. The design technique alternates between analytic computation of single bunch optimal controllers and verification on a multibunch numerical simulator. The simulator identifies unstable coupled bunch modes and predicts their growth and damping rates. The results from the simulator are shown to be in reasonable agreement with analytical calculations based on the singlemore » bunch model. The technique is then used to evaluate the performance of a variety of controllers proposed for PEP-II.« less
  • We present a technique for the design and verification of efficient bunch-by-bunch controllers for damping longitudinal multibunch instabilities. The controllers attempt to optimize the use of available feedback amplifier power - one of the most expensive components of a feedback system - and define the limits of the closed loop system performance. Our design technique alternates between analytic computation of single bunch optimal controllers and verification on a multibunch numerical simulator. The simulator uses PEP-II parameters and identifies unstable coupled bunch modes, their growth rates and their damping rates with feedback. The results from the simulator are shown to bemore » in reasonable agreement with analytical calculations based on the single bunch model. The technique is then used to evaluate the performance of a variety of controllers proposed for PEP-II.« less
  • The authors use MAFIA to analyze the PEP-II button-type beam position monitors (BPMs). Employing proper termination of the BPM into a coaxial cable, the output signal at the BPM can be determined. Thus the issues of sensitivity and power output can be addressed quantitatively, including all transient effects and wakefields. Besides this first quantitative analysis of a true BPM 3D structure, they find that internal resonant modes are a major source of high value narrow-band impedances. These are evaluated and methods are presented to suppress these parasitic resonances below the tolerable limit of multibunch instabilities.