Quenching factor for alpha particles in ZnSe scintillating bolometers

S Nagorny,L Pagnanini,S Pirro,K Schaeffner,N Casali,L Cardani,L Pattavina,I Dafinei

doi:10.1088/1757-899x/169/1/012011

Abstract

In the framework of the CUPID-0 experiment, a numbers of ZnSe single crystals were produced and subjected to different thermal treatments, and later tested as cryogenic scintillating bolometers. We have found that a specific thermal treatment (24 hours under argon atmosphere at 900 °C) has a strong impact on some properties of ZnSe crystals (amplitude of signal, light yield, specific resistivity) and most interestingly, changes the quenching factor for alpha particles from values > 1 to values < 1. Thus such thermal treatment opens the possibility to modify this experimental parameter for a various applications.

Highlights

Cryogenic scintillating bolometers are a promising technology to explore diverse rare nuclear processes like rare alpha decay, rare or forbidden beta decays, neutrinoless double beta decay, which have characteristic decay times larger than 1014 y
ZnSe scintillating bolometers are the fundamental technology of the CUPID-0 experiment which is searching for neutrinoless double beta decay of 82Se
We have found that the anomalous Quenching Factor (QF) for alpha particles in ZnSe crystals depends on certain type of defects and it can be adjusted by thermal treatment

Summary

Introduction

Cryogenic scintillating bolometers are a promising technology to explore diverse rare nuclear processes like rare alpha decay, rare or forbidden beta decays, neutrinoless double beta decay, which have characteristic decay times larger than 1014 y. The main feature of scintillating bolometers is the simultaneous heat release and light emission caused an interacting particle in the crystal. The bolometers possess a very good energy resolution and nearly 100% detection efficiency. ZnSe crystals have an interesting feature: alpha particles produce more light than electrons at the same deposited energy in the detector, i.e. Quenching Factor (QF) is greater than unity. To our knowledge no other scintillator with a QF for alphas greater than 1 has ever been reported in literature.

Published under licence by IOP Publishing Ltd

Doping undoped undoped

After TT

Findings

Discussion and summary