Monte Carlo simulation of the muon-induced background of an anti-Compton gamma-ray spectrometer placed in a surface and underground laboratory

摘要

Simulations of the cosmic ray muon induced background of a HPGe detector placed inside an anti-Compton shield on the surface and shallow underground is described. Investigation of several model set-ups revealed some useful trends for design of low-level gamma-ray spectrometers. It has been found that the background spectrum of a HPGe detector can be scaled down with the shielding depth. No important difference is observed when the same set-up of the anti-Compton spectrometer is positioned horizontally or vertically. A cosmic-muon rejection factor of at least 40 (at around 1 MeV) can be reached when the anti-Compton suppression is operational. The cosmic-muon background can be reduced to such a level that other background components prevail, like those from the residual contamination of the detector and shield materials and/or from radon, especially for the underground facilities.