Energetic neutron identification with pulse shape discrimination in pure CsI crystals

TL;DR

This study demonstrates that pure CsI scintillators can effectively distinguish energetic neutron interactions from cosmic muons using pulse shape discrimination, offering potential improvements in particle identification at physics experiments.

Contribution

It shows that pure CsI can be used for effective neutron vs. muon discrimination via pulse shape analysis, with potential for enhanced shower identification in particle physics.

Findings

Pulse shape discrimination with pure CsI is effective for neutron vs. muon separation.

Pure CsI's neutron interaction rate correlates with beam power.

Pure CsI cannot resolve specific neutron inelastic interactions like CsI(Tl).

Abstract

Pulse shape discrimination with pure CsI scintillators is investigated as a method for separating energy deposits by energetic neutrons and photons at particle physics experiments. Using neutron data collected near the European XFEL XS1 beam window the pulse shape discrimination capabilities of pure CsI are studied and compared to CsI(Tl) using near-identical detector setups, which were operated in parallel. The inelastic interactions of 100MeV neutrons are observed to produce a slower scintillation emission in pure CsI relative to energy deposits from cosmic muons. By employing a charge-ratio method for pulse shape characterization, pulse shape discrimination with pure CsI is shown to be effective for identifying energy deposits from neutrons vs. cosmic muons, however, pure CsI was not able resolve the specific type of neutron inelastic interactions as can be done with CsI(Tl). Using pulse shape discrimination, the rate of energetic neutron interactions in a pure CsI detector is measured as a function of time and shown to be correlated with the European XFEL beam power. The results demonstrate that pulse shape discrimination with pure CsI has significant potential to improve electromagnetic vs. hadronic shower identification at future particle physics experiments.