Characterization study of a broad-energy germanium detector at CJPL

TL;DR

This study thoroughly characterizes a broad-energy germanium detector's parameters, such as energy resolution, efficiency, and dead layer thickness, to enhance its application in neutrinoless double beta decay experiments at CJPL.

Contribution

It provides detailed measurement procedures and results for a BEGe detector's key parameters, aiding future 0νββ experiments at CJPL.

Findings

Dead layer thicknesses are approximately 0.17 mm on the front and 1.18 mm on the side.

Energy resolution and linearity were successfully measured using point-like sources.

Efficiency calibration was performed with a cylindrical volume source.

Abstract

The ability of background discrimination using pulse shape discrimination (PSD) in broad-energy germanium (BEGe) detectors makes them as competitive candidates for neutrinoless double beta decay (0{\nu}\b{eta}\b{eta}) experiments. The measurements of key parameters for detector modeling in a commercial p-type BEGe detector are presented in this paper. Point-like sources were used to investigate the energy resolution and linearity of the detector. A cylindrical volume source was used for the efficiency calibration. With an assembled device for source positioning, a collimated 133Ba point-like source was used to scan the detector and investigate the active volume. A point-like source of 241Am was used to measure the dead layer thicknesses, which are approximately 0.17 mm on the front and 1.18 mm on the side. The described characterization method will play an important role in the 0{\nu}\b{eta}\b{eta} experiments with BEGe detectors at China JinPing underground Laboratory (CJPL) in the future.