Construction and test of a transition-radiation detector prototype based on thick gas electron multiplier technology

A transition-radiation detector (TRD) is a powerful device for highly relativistic electron (gamma >= 1,000) identification. Electron identification is crucial for tagging the outgoing scattered electrons in an electron-ion collider (EIC) detector. Employing a TRD at the electron forward region of an EIC detector can provide the necessary electron identification with high hadron rejection over a wide momentum range. Thick gas electron multiplier (THGEM) technology is suitable for radiation detection in modern high-energy experiments owing to its high-granularity structure, radiation hardness, high-rate capability and ease of large-area production. This study investigates a TRD prototype based on THGEM technology through soft X-ray and electron beam experiments. Geant4 simulation were extensively exploited to understand the operation of TRD prototype with different gas mixtures. Particularly, the performance of TRD prototype with an electron beam at the DESY, with argon-based gas rather than xenon-based gas, agreed well with the simulation analyses in all important aspects. Based on the consistency of the experimental and simulation results, a likelihood analysis on the simulated total energy deposit in the xenon-based working gas would suggest a pion rejection improvement with the optimization of detector design, readout electronics and identification algorithm.