Effect of large-angle incidence on particle identification performance for light-charged ($Z \le 2$) particles by pulse shape analysis with a pad-type nTD silicon detector

TL;DR

This study investigates how large incident angles affect the ability of pulse shape analysis with pad-type nTD silicon detectors to discriminate light-charged particles, revealing angle-dependent changes in detector response.

Contribution

It provides new insights into the impact of incident angle on particle discrimination performance using digital waveform analysis for light-charged particles.

Findings

Maximum current decreases with increasing incident angle.

Discrimination performance is affected by the penetration depth of particles.

Performance degradation correlates with incident angle and particle type.

Abstract

In recent years, particle discrimination methods based on digital waveform analysis techniques for neutron-transmutation-doped silicon (nTD-Si) detectors have become widely used for the identification of low-energy charged particles. Although the particle discrimination capability of this method has been well demonstrated for small incident angles, the particle discrimination performance may be affected by changes in the detector response when the detector is moved closer to the charged particle source and the incident position distribution and incident angle distribution to the detector become wide. In this study, we performed a beam test for particle discrimination in light-charged ($Z \le 2$) particles using the digital waveform analysis method with a pad-type nTD-Si detector and investigated the dependence of the performance of the particle discrimination on the incident position and incident angle. As the incident angle increased, a decrease in the maximum current was observed, which was sufficient to affect the performance of the particle discrimination. This decrease can be expressed as a function of the penetration depth of the charged particles into the detector, which varies for each nuclide.