The polymerization phenomenon on thick gas electron multiplier (THGEM) detectors in self-quenching streamers mode (SQS)

One of the most important limitations of gas detectors is the phenomenon of polymerization. This factor can disrupt the overall performance of the detector. The occurrence of this phenomenon has been observed and proven in wired detectors. In this paper, the polymerization phenomenon on thick gas electron multiplier detectors (THGEM) in self-quenching streamer (SQS) mode has been investigated using a 137Cs gamma source with 3.95µCi(1.46×105Bq) activity. In the presence of an approximate amount (10%) of a hydrocarbon gas such as methane, which is used as a quencher in the P10 gas composition, it is observed that after three days the detector is used an average of three to four hours per day. Sudden changes in the counting rate and also electrical sparks are seen. According to the images and observations, the harmful effects of hydrocarbon gas polymerization, which is one of the main factors of this phenomenon, have been proven in THGEM detectors, and suggestions have been made to improve and extend the life of the system.