Determination of the electric field in highly-irradiated silicon sensors using edge-TCT measurements

TL;DR

This paper introduces a novel method to determine the electric field and charge density in highly-irradiated silicon sensors using edge-TCT measurements, validated through simulations and applied to irradiated sensors to study radiation damage effects.

Contribution

The paper presents a new technique for extracting position-dependent electric fields and charge densities from edge-TCT data in irradiated silicon sensors, expanding understanding of radiation effects.

Findings

Method accurately describes velocity profiles in irradiated sensors

Electric fields and charge densities reveal radiation damage effects

Validated with simulations and experimental data

Abstract

A method is presented which allows to obtain the position-dependent electric field and charge density by fits to velocity profiles from edge-TCT data from silicon strip-detectors. The validity and the limitations of the method are investigated by simulations of non-irradiated $n^+p$ pad sensors and by the analysis of edge-TCT data from non-irradiated $n^+p$ strip-detectors. The method is then used to determine the position dependent electric field and charge density in $n^+p$ strip detectors irradiated by reactor neutrons to fluences between 1 and $10 \times 10^{15}$ cm$^{-2}$ for forward-bias voltages between 25 V and up to 550 V and for reverse-bias voltages between 50 V and 800 V. In all cases the velocity profiles are well described. The electric fields and charge densities determined provide quantitative insights into the effects of radiation damage for silicon sensors by reactor neutrons.