Angular dependence of columnar recombination in high pressure xenon gas using time profile of scintillation emission

TL;DR

This study investigates how the angle of nuclear tracks in high-pressure xenon gas affects scintillation and ionization signals, revealing potential for directional dark matter detection through time-profile analysis.

Contribution

It demonstrates that the track angle can be reconstructed from scintillation time profiles, advancing directional detection techniques in xenon gas detectors.

Findings

Slow scintillation component increases with track alignment to electric field.

Fast scintillation component shows no angular dependence.

Track angle can be inferred from scintillation time profile.

Abstract

The angular dependence of the columnar recombination in xenon gas, if observed for low energy nuclear tracks, can be used for a direction-sensitive dark matter search. We measured both scintillation and ionization to study columnar recombination for 5.4 MeV alpha particles in a high pressure gas detector filled with 8 atm xenon. Since the recombination photons are emitted several~$\mu$s after de-excitation emission, scintillation photons are separated to the fast and slow components. The fast component does not show dependence on the track angle relative to the drift electric field, on the other hand, the slow component increases when the track is aligned with the electric field. The result indicates that the track angle relative to the electric field can be reconstructed from the scintillation time profile.