TY - JOUR
T1 - Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period
AU - Aad, G.
AU - Abbott, B.
AU - Abdallah, J.
AU - Abdinov, O.
AU - Abeloos, B
AU - Aben, R.
AU - Abolins, M.
AU - AbouZeid, O.S.
AU - Nitzan, Abraham
AU - Abramowicz, H.
AU - Dam, Mogens
AU - Hansen, Jørn Dines
AU - Hansen, Jørgen Beck
AU - Xella, Stefania
AU - Hansen, Peter Henrik
AU - Petersen, Troels Christian
AU - Pingel, Almut Maria
AU - Alonso Diaz, Alejandro
AU - Monk, James William
AU - Galster, Gorm Aske Gram Krohn
AU - Thomsen, Lotte Ansgaard
AU - Løvschall-Jensen, Ask Emil
AU - Pingel, Almut Maria
AU - Pedersen, Lars Egholm
AU - Wiglesworth, Graig
AU - Pedersen, Lars Egholm
PY - 2016/5/20
Y1 - 2016/5/20
N2 - 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.
AB - 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.
U2 - 10.1088/1748-0221/11/05/P05013
DO - 10.1088/1748-0221/11/05/P05013
M3 - Journal article
SN - 1748-0221
VL - 11
JO - Journal of Instrumentation
JF - Journal of Instrumentation
M1 - P05013
ER -