Position Reconstruction in a Dual Phase Xenon Scintillation Detector

TL;DR

This paper explores statistical algorithms for event position reconstruction in a dual phase xenon detector, demonstrating improved spatial and energy resolution for dark matter detection and potential medical imaging applications.

Contribution

It introduces an iterative method for in-situ PMT response calibration and applies statistical reconstruction algorithms to enhance detector performance.

Findings

Achieved 13 mm spatial resolution for primary scintillation

Achieved 1.6 mm spatial resolution for secondary scintillation

Obtained 8.1% energy resolution at 122 keV

Abstract

We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated gamma-ray source. Using the techniques described, the performance of the ZEPLIN-III dark matter detector was studied for 122 keV gamma-rays. For the inner part of the detector (R<100 mm), spatial resolutions of 13 mm and 1.6 mm FWHM were measured in the horizontal plane for primary and secondary scintillation, respectively. An energy resolution of 8.1% FWHM was achieved at that energy. The possibility of using this technique for improving performance and reducing cost of scintillation cameras for medical applications is currently under study.