Background Radiation Studies at LHCb Using Geant4

Abstract—This paper aims to describe the feasibility studies per-formed to evaluate the background radiation levels in the LHCb experiment with Geant4. LHCb is one of the experiments that will operate at the LHC (Large Hadron Collider) under construction at CERN. The simulation toolkit Geant4 has been used to model the interactions of particles with the detector. Geant4 is a software toolkit developed and maintained by a world-wide collaboration of physicists and computer scientists. The principal monitored distri-butions in this study are the dose and the fluence of certain particles in specific locations of the experiment. The dose is defined as the en-ergy delivered in a volume per unit of the volume mass, while the fluence is defined as the number of particles passing through a sur-face per unit of area. Energy spectra need also to be evaluated to take into account the energy distribution of these particles, since specific problems in the electronics can be caused by particles of certain energies. For this purpose, we need to tally doses and fluences using Geant4. The 2D mapping of doses and fluences of charged hadrons, neu-trons, gammas, electrons and positrons on planes put in specific critical areas, where the electronics is located, have been obtained. Geant4 provides different physics models to describe interaction processes allowing customization of the simulation engine to spe-cific problems. Preliminary results using different relevant physics models are presented. Index Terms—Dosimetry, LHCb, Monte Carlo methods