A high rejection transition radiation detector prototype to distinguish positrons from protons in a cosmic ray space laboratory

Abstract

We have carefully implemented a transition radiation detector prototype in order to design a similar device having 75 × 150 cm2 active surface that will discriminate positrons from protons. This detector will be part of the spectrometer of the experiment WIZARD, planned to fly at 180 miles altitude on the NASA Space Station “FREEDOM” to search for primordial antimatter. Since the positron to proton ratio is expected to be of the order of 10−4, we have pushed the proton rejection factor of the spectrometer beyond this value using a compact transition radiation detector equipped with properly designed “cluster counting” electronics.