Development of a thick gas electron multiplier-based beta-ray detector

A new beta-ray detector using Thick Gas Electron Multiplier (THGEM) technology is presented. Traditional proportional counters have been considered the standard for many decades for radiation contamination monitoring. However, it has always been challenging to detect low energy beta-emitters like 3H and 14C. In order to extend the low energy cutoff of these beta particles, it is important to keep the electron multiplication gain as high as possible. To accomplish this goal, we have developed a new gaseous beta-ray detector using THGEMs. Founded on previous THGEM avalanche simulations [1] and predecessor detectors, a prototype THGEM beta-ray detector was designed and fabricated. Its signal performance, effective gain and gain stability were comprehensively studied for single and double-THGEM configurations using an alpha source. The response of the detector to beta-rays was measured for various operating conditions and compared with MCNP6 Monte Carlo simulations.