Measurements and optimization of the light yield of a TeO$_2$ crystal

TL;DR

This paper measures and optimizes the Cherenkov light yield in TeO₂ crystals for bolometric detectors, demonstrating a light yield of about 52 photons/MeV and exploring wrapping effects to enhance light collection.

Contribution

It introduces a method to evaluate Cherenkov light in TeO₂ crystals and compares experimental results with detailed simulations, advancing detector discrimination techniques.

Findings

Measured Cherenkov light yield of ~52 photons/MeV.

Demonstrated impact of PTFE wrapping on light collection.

Validated simulation results with experimental data.

Abstract

Bolometers have proven to be good instruments to search for rare processes because of their excellent energy resolution and their extremely low intrinsic background. In this kind of detectors, the capability of discriminating alpha particles from electrons represents an important aspect for the background reduction. One possibility for obtaining such a discrimination is provided by the detection of the Cherenkov light which, at the low energies of the natural radioactivity, is only emitted by electrons. This paper describes the method developed to evaluate the amount of light produced by a crystal of TeO$_2$ when hit by a 511 keV photon. The experimental measurements and the results of a detailed simulation of the crystal and the readout system are shown and compared. A light yield of about 52 Cherenkov photons per deposited MeV was measured. The effect of wrapping the crystal with a PTFE layer, with the aim of maximizing the light collection, is also presented.