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Fieguth, H.

Paper Title Page
TPPP023 Simulation of PEP-II Accelerator Backgrounds Using TURTLE 1835
 
  • R.J. Barlow, H. Fieguth
    SLAC, Menlo Park, California
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • S.A. Majewski
    Stanford University, Stanford, Califormia
  • P. Roudeau, A. Stocchi
    LAL, Orsay
 
  We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using a modified version ofthe 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 programme of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modelling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.  
TPPP025 Modeling Lost-Particle Accelerator Backgrounds in PEP-II Using LPTURTLE 1889
 
  • H. Fieguth, R.J. Barlow
    SLAC, Menlo Park, California
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
 
  Funding: Department of Energy Contract DE-AC02-76SF00515.

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 a modified version of Decay 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.

 
TPPP032 Proposal for a Multi-Use Test Beam Area in the SLAC B-Line 2221
 
  • P. Emma, L.D. Bentson, R.A. Erickson, H. Fieguth, J. Seeman, A. Seryi
    SLAC, Menlo Park, California
 
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.

With the impending construction of the Linac Coherent Light Source (LCLS) at SLAC, displacing the well-used Final Focus Test Beam (FFTB) area, there is growing interest in developing a new test beam facility, available during LCLS operations and located in the old B-Line tunnel at the end of the linac. The success of the Sub-Picosecond Pulse Source (SPPS) and the desire to preserve this capacity suggests a new beamline with similar or improved electron beam quality, including bunch length compression to 10 microns. Beam availability during LCLS operations requires a new 1.2-km bypass line connecting the 2/3-point of the linac with the B-Line. A second operating mode, with LCLS not in use, involves a trajectory directly from the end of the linac to the B-line. This feature provides the highest beam quality at 30 GeV, and also allows a possible third operational mode by deflecting a few of the very high-brightness 120-Hz, 14-GeV LCLS bunches at low rate (1-10 Hz) into the B-line. Finally, linear collider research can be carried out in a short final focus system at the end of the B-Line, capable of producing a 70-nm rms beam size. We describe a possible design for these systems.

 
WPAE056 Geant4-Based Simulation Study of PEP-II Beam Backgrounds in the BaBar Detector at the SLAC B-Factory 3351
 
  • W.S. Lockman
    SCIPP, Santa Cruz, California
  • D. Aston, G.R. Bower, M. Cristinziani, H. Fieguth, D. H. Wright
    SLAC, Menlo Park, California
  • N.R. Barlow, C.L. Edgar
    Manchester University, Manchester
  • N.L. Blount, D. Strom
    University of Oregon, Eugene, Oregon
  • M. Bondioli
    INFN-Pisa, Pisa
  • G. Calderini
    UNIPI, Pisa
  • B. Campbell, S.H. Robertson
    CHEP, Montreal, Quebec
  • W. Kozanecki
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • B.A. Petersen
    Stanford University, Stanford, Califormia
 
  To improve the understanding of accelerator-induced backgrounds at the SLAC B-Factory and validate the proposed PEP-II luminosity upgrade, we simulate lost-particle backgrounds in the BaBar detector originating from beam-gas interactions and radiative-Bhabha scatters. To perform this study, we have extended the GEANT4-based BaBar detector simulation to include PEP-II beam-line components and magnetic fields up to 10m away from the interaction point. We first describe the simulation model and then compare predicted background levels with measurements from dedicated single-and colliding-beam experiments. Finally, we compare the simulated background levels in the current and the proposed luminosity-upgrade configurations.