Characterization and performance of the DTAS detector

TL;DR

This paper thoroughly characterizes the DTAS segmented NaI(Tl) gamma-ray spectrometer's performance, including calibration, gain correction, and neutron interaction analysis, to enhance its application in total absorption gamma-ray spectroscopy at FAIR.

Contribution

It introduces a comprehensive procedure for detector calibration, gain correction, and neutron interaction analysis, improving the accuracy of total absorption gamma-ray spectroscopy measurements.

Findings

Effective gain stabilization using light pulse generators.

Accurate reconstruction of deposited energy despite non-proportionality.

Detailed analysis of neutron interactions affecting measurements.

Abstract

DTAS is a segmented total absorption {\gamma}-ray spectrometer developed for the DESPEC experiment at FAIR. It is composed of up to eighteen NaI(Tl) crystals. In this work we study the performance of this detector with laboratory sources and also under real experimental conditions. We present a procedure to reconstruct offline the sum of the energy deposited in all the crystals of the spectrometer, which is complicated by the effect of NaI(Tl) light-yield non-proportionality. The use of a system to correct for time variations of the gain in individual detector modules, based on a light pulse generator, is demonstrated. We describe also an event-based method to evaluate the summing-pileup electronic distortion in segmented spectrometers. All of this allows a careful characterization of the detector with Monte Carlo simulations that is needed to calculate the response function for the analysis of total absorption {\gamma}-ray spectroscopy data. Special attention was paid to the interaction of neutrons with the spectrometer, since they are a source of contamination in studies of \b{eta}-delayed neutron emitting nuclei.