Background identification in cryogenic calorimeters through $\alpha-\alpha$ delayed coincidences

TL;DR

This paper introduces a novel method using alpha-alpha delayed coincidences to identify and distinguish surface and bulk radioactive contaminations in cryogenic calorimeters, aiding background reduction in low-background experiments.

Contribution

The paper presents an innovative technique based on alpha-alpha delayed coincidences to analyze contaminations in cryogenic detectors, improving localization accuracy.

Findings

Effective discrimination between surface and bulk contaminations.

Enhanced understanding of contamination distribution in detectors.

Potential for improved background modeling in experiments.

Abstract

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 $^{232}$Th and $^{238}$U 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 $\alpha$ decay position.