New methods to identify low energy 3He with Silicon-based detectors

Abstract

Methods to discriminate low energy mass-3 particles using Silicon detectors are reviewed. The time-of-flight technique based on analog electronics and measuring time between a reference signal and the charge signal from the Silicon detector does not allow to discriminate 3He from 3H. One method consists in adding a thin layer of Silicon (typically of 20μm) to recover the standard discrimination by ΔE-E identification matrix. Strong inhomogeneities in thickness are observed for these thin detectors. Difficulties in handling such detectors have led to investigate numerical approaches using reverse-mounted neutron transmutation doped Silicon detectors. First, the pulse shape analysis (PSA) technique has been investigated on the current and charge signals. PSA enables the discrimination of tritons and 3He and also 3He and 4He with good figures of merit. Secondly, the time of flight between two digitized signals (a reference signal from the beam pulse and the current or the charge signal) is presented. Both numerical techniques give promising results for the identification of light particles with Silicon detectors.