Data sorting modes of phoswich detector array

TL;DR

This study investigates various data-sorting modes of the PARIS phoswich detector array, demonstrating its capabilities in gamma-ray detection, event rejection, and spectral purity improvements for high-energy gamma-ray spectroscopy.

Contribution

It introduces specific data-sorting modes for PARIS and evaluates their effectiveness in decay spectroscopy, highlighting advantages over traditional detection methods.

Findings

PARIS effectively rejects escape and pileup events.

Using NaI(Tl) as a veto improves spectral purity.

Add-back analysis enhances full-energy peak efficiency.

Abstract

The different data-sorting modes of the phoswich detector array PARIS used for detecting high-energy (4$-$10 MeV) $\gamma$ rays are investigated. The characteristics including time resolution, energy resolution and detection efficiency under various modes are studied. The present study shows that PARIS has capabilities of rejecting escape and pileup events when used for decay spectroscopy. Notably, the methods presented in this work refer specifically to the $\beta$-decay experiment of $^{80g+m}$Ga conducted with three PARIS clusters comprising 27 phoswich detectors, rather than to a general report on the PARIS array or its overall performance for in-beam spectroscopy. Compared with the 2"$\times$2"$\times$2" LaBr$_3$(Ce) detector (Ciema{\l}a et al., 2009), even in individual mode, PARIS provides significant suppression of single- and double-escape peaks and reduces background via vetoing function of the outer-volume NaI(Tl) crystals. In contrast to the common approach of adding back the energies in LaBr$_3$(Ce) and NaI(Tl) to increase the detection efficiency of the full-energy peak, using NaI(Tl) as a veto shield provides a superior trade-off for applications where spectral purity is essential. Employing add-back analysis within each cluster of nine phoswiches or between all phoswiches could enhance full-energy peak efficiency and further suppress escape peaks and background. Applying a multiplicity condition provides a further suppression but simultaneously lowers the statistics of full-energy peaks.