Background radiation studies at LHCb using Geant4

Preliminary results of simulation studies performed to evaluate the background radiation levels in the LHCb experiment are presented in the paper. 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 distributions in this study are the dose and fluence of certain particles in specific locations of the experiment. Energy spectra need also to be evaluated in order to take into account the energy distribution of these particles, since specific problems in the electronics can be raised by particles of certain energies. To this purpose, we need: 1) Tallying doses and fluences in Geant4. 2) These quantities are generally calculated on a plane or a cylindrical surface that should not interfere with the real geometry of an experimental setup. This feature is not yet fully functional in Geant4 and not used in these studies. The 2D maps of doses and fluences of charged hadrons, neutrons, electrons and positrons, gammas 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 specific problems. Preliminary results using different relevant physics models are presented.