Modeling the Charge Collection Efficiency in the Li-diffused Inactive Layer of a P-type Point-Contact Germanium Detector

TL;DR

This paper presents a model for the charge collection efficiency in the Li-diffused inactive layer of P-type germanium detectors, validated with experimental data, and discusses how Li doping affects detector performance.

Contribution

The paper introduces a new model for charge collection efficiency in Li-diffused layers of P-type germanium detectors, applicable to various detector geometries.

Findings

Model accurately predicts charge collection efficiency curves.

Validation shows good agreement with experimental measurements.

Li doping processes influence charge collection efficiency.

Abstract

A model of the Li-diffused inactive layer in P-type high purity germanium detectors is built to describe the transportation of charge carriers and calculate the charge collection efficiency therein. The model is applied to calculate charge collection efficiency of a P-type point-contact germanium detector used in rare event physics experiments and validated in another P-type semi-planar germanium detector. The calculated charge collection efficiency curves are well consistent with measurements for both detectors. Effects of the Li doping processes on the charge collection efficiency are discussed based on the model. This model can be easily extended to other P-type germanium detectors, for instance, the P-type broad-energy Ge detector, and the P-type inverted-coaxial point-contact detector.