Rejection of α-particle background for neutrinoless double beta decay search with pixel detectors

Abstract

Experiments searching for the neutrinoless double beta decay require a very low level of background. Most experiments aim for a background rate of about 10 −4 to 10 −3 events kg • keV • yr . αparticles can be an important part of the background since they occur as decay products of many isotopes in the natural decay chains. They are emitted with kinetic energies of a few MeV and therefore produce background at the Q-value of most double beta isotopes. In this publication we demonstrate experimentally that α-particle background can be reduced by about six orders of magnitude exploiting its topology of triggered pixels which is different from neutrinoless double beta decay of 116 Cd.

Improvement of the energy resolution of pixelated CdTe detectors for applications in 0νββsearches

“…This would offer the possibility of background rejection by identifying the particles by their track topologies. We already showed that alpha particle background can be reduced by at least a factor of 4.32 • 10 5 with a 0νβ β signal loss of less than 4.5% [9]. Single electron background can be rejected by 75% with a signal loss of about 25% [10].…”