Reconstruction of a Radiation Point Source's Radial Location Using Goodness-of-Fit Test on Spectra Obtained from an HPGe Detector

TL;DR

This paper demonstrates that a goodness-of-fit test on spectra from HPGe detectors can effectively determine the radial position of a point radiation source, with accuracy depending on the number of detected counts.

Contribution

The study introduces a method using the Kolmogorov-Smirnov test on spectral shapes to reconstruct the radial location of point sources with HPGe detectors.

Findings

Spectral shape sensitivity varies with source position.

Good radial localization achieved using spectral shape analysis.

Position reconstruction accuracy improves with more counts.

Abstract

High purity germanium (HPGe) detectors are ubiquitous in nuclear physics experiments and are also used in numerous low radioactive background detectors. The effect of the position of $^{60}$Co and $^{137}$Cs point sources on the shape of spectra were studied with Monte Carlo and HPGe detector measurements. We briefly confirm previous work on the position dependence of relative heights of peaks. Spectra taken with the radiation sources placed at locations around the detector were then compared using the Kolmogorov-Smirnov (K-S) goodness-of-fit test. We demonstrate that with this method the Compton continuum spectral shape has good sensitivity to the radial location of a point-source, but poor angular resolution. We conclude with a study of the position reconstruction accuracy as a function of the number of counts from the source.