Results of dedicated Monte Carlo simulations of beam-induced background (BIB)
in the ATLAS experiment at the Large Hadron Collider (LHC) are presented and
compared with data recorded in 2012. During normal physics operation this
background arises mainly from scattering of the 4 TeV protons on residual gas
in the beam pipe. Methods of reconstructing the BIB signals in the ATLAS
detector, developed and implemented in the simulation chain based on the FLUKA
Monte Carlo simulation package, are described. The interaction rates are
determined from the residual gas pressure distribution in the LHC ring in order
to set an absolute scale on the predicted rates of BIB so that they can be
compared quantitatively with data. Through these comparisons the origins of the
BIB leading to different observables in the ATLAS detectors are analysed. The
level of agreement between simulation results and BIB measurements by ATLAS in
2012 demonstrates that a good understanding of the origin of BIB has been
reached.
