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Torsten ÅKESSON

Torsten Åkesson

Professor

Torsten ÅKESSON

Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

Author

  • G Aad
  • B. Abbott
  • J Abdallah
  • O Abdinov
  • B Abeloos
  • R Aben
  • Torsten Åkesson
  • Simona Bocchetta
  • Lene Bryngemark
  • Caterina Doglioni
  • Anders Floderus
  • Anthony Hawkins
  • Vincent Hedberg
  • Jenny Ivarsson
  • Göran Jarlskog
  • Else Lytken
  • Ulf Mjörnmark
  • Oxana Smirnova
  • Oleksandr Viazlo

Summary, in English

This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency buckets of the LHC can be resolved. Some results of two short periods of dedicated cosmic-ray background data-taking are shown; in particular cosmic-ray muon induced fake jet rates are compared to Monte Carlo simulations and to the fake jet rates from beam background. A thorough analysis of a particular LHC fill, where abnormally high background was observed, is presented. Correlations between backgrounds and beam intensity losses in special fills with very high β∗ are studied. © 2016 CERN for the benefit of the ATLAS collaboration.

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2016

Language

English

Publication/Series

Journal of Instrumentation

Volume

11

Issue

5

Document type

Journal article

Publisher

IOP Publishing

Topic

  • Subatomic Physics

Keywords

  • Beam-intensity monitors
  • Beam-line instrumentation (beam position and profile monitors
  • Bunch length monitors)
  • Data analysis
  • Performance of high energy physics detectors
  • Cosmology
  • Data reduction
  • High energy physics
  • Intelligent systems
  • Monte Carlo methods
  • Beam intensity
  • Beam positions
  • Bunch length
  • Cosmic Ray Background
  • Cosmic-ray muons
  • High energy physics detector
  • Radio frequencies
  • Residual pressures
  • Cosmic rays

Status

Published

ISBN/ISSN/Other

  • ISSN: 1748-0221