Background identification in cryogenic calorimeters through α - α delayed coincidences

Localization and modeling of radioactive contaminations is a challenge that ultra-low background experiments are constantly facing. These are fundamental steps both to extract scientific results and to further reduce the background of the detectors. Here we present an innovative technique based on the analysis of alpha-alpha delayed coincidences in Th-232 and U-238 decay chains, developed to investigate the contaminations of the ZnSe crystals in the CUPID-0 experiment. This method allows to disentangle surface and bulk contaminations of the detectors relying on the different probability to tag delayed coincidences as function of the a decay position.

Automated summary

The localization and modeling of radioactive contaminations is a challenge for ultra-low background experiments. An innovative technique based on alpha-alpha delayed coincidences has been developed to investigate contaminations in detectors, allowing to differentiate between surface and bulk contaminations.