Investigation of optical property modulation based ionizing radiation detection method for PET: two-crossed-polarizers based method

In this paper, a novel optical setup based on two-crossed-polarizers is introduced to achieve ionizing radiation detection, which is an easy-build-up setup with equivalent ionizing radiation detection ability as previous work [1], [2], [3]. The performance of our proposed setup with Lithium Niobate (LiNbO
₃
) and Cadmium Telluride (CdTe) detector crystals was evaluated. The 511keV photons induced modulation signal could be detected using two-crossed-polarizer based method with LiNbO
₃
and CdTe as detector. Moreover, the strength of modulation signal is linear proportion with bias voltage before being saturated. Due to LiNbO
₃
's high resistivity (which could reduce the dark current), its modulation signal strength keeps increased trend after 2000V, while that signal of CdTe tended to be saturated at voltage higher than 1200V since CdTe with lower resistivity. Therefore, to improve the detection sensitivity for 511keV, we could further increase the bias voltage for detector crystals (especially for detector with high resistivity).