Measurement of the dead layer thickness in a p-type point contact germanium detector

TL;DR

This paper presents a method to measure the dead layer thickness in a p-type point contact germanium detector using a 133Ba source, crucial for accurate detector mass estimation in dark matter searches.

Contribution

It introduces a novel measurement technique combining experimental data and Monte Carlo simulation to accurately determine the dead layer thickness.

Findings

Dead layer thickness measured as 1.02 mm

Method achieves good agreement between data and simulation

Provides a reliable approach for detector characterization

Abstract

A 994g mass p-type PCGe detector was deployed by the first phase of the China Dark matter EXperiment aiming at the direct searches of light weakly interacting massive particles. Measuring the thickness of the dead layer of a p-type germanium detector is an issue of major importance since it determines the fiducial mass of the detector. This work reports a method using an uncollimated 133Ba source to determine the dead layer thickness. The experimental design, data analysis and Monte Carlo simulation processes, as well as the statistical and systematic errors are described. An agreement between the experimental data and simulation results was achieved to derive the thickness of the dead layer of 1.02 mm.