Cosmic muon effect in the background of a Si/Si coincidence measurement: Study and application

The PIPSBox is a new high resolution electron spectrometer composed of two Si-PIN detectors developed by CEA. It is designed for the measurement of radioxenons by means electron/photon coincidences when coupled to a NaI(Tl) or HPGe detector. Alternatively, electron/electron (or Si/Si) coincidences can be studied when focusing on events depositing energy in its two Si-PIN detectors simultaneously. In this paper, such Si/Si coincidence measurements are studied. Especially, it is shown (using Monte-Carlo simulations) that the Si/Si background coincidence spectrum is dominated by secondary cosmic muons. Finally, the cosmic veto efficiency of the γ3 spectrometer (a recently developed low-background ground-based photon spectrometer (Cagniant et al., 2015)) was estimated to be 99.0±0.7% thanks to Si/Si coincidence measurements inside its shielding.