Digital alpha-electron discrimination with a silicon detector and its application as an auxiliary detector in the alpha TOF spectrometer

Abstract

Alpha Time-Of-Flight (A-TOF) spectroscopy is commonly used to measure alpha particles in high-energy resolution. To minimize interference from background radiation and prevent random TOF registrations during long-time measurements, specific strategies are necessary. One effective approach involves incorporating an auxiliary detector at the end of the flight vacuum tube. In this configuration, the alpha particle is registered only when detected by the auxiliary detector at the end of its trajectory. In this work, an ion-implanted silicon detector is used as an auxiliary detector to discriminate alpha from other radiations, such as electrons produced from photon interactions with materials in the structure of the TOF spectrometer. A simple setup using a digitizer is presented to investigate the ability of the silicon detector to discriminate between alpha particles and electrons. This technique distinguishes between alpha and electron particles using the charge integration method, implemented in the DPP-PSD firmware of the digitizer. The performance of the setup was experimentally evaluated using a²⁴¹Am source, which emits both alpha particles and conversion electrons. The results demonstrated that it is possible to effectively distinguish between alpha particles and electrons through charge comparisons of the sampled signals from the silicon detector. Thus, this technique can contribute to the development of A-TOF spectrometers by minimizing the interference from background radiation and random noise in time registrations during long-term measurements.