@misc{oai:repo.qst.go.jp:00083571,
 author = {Fumihiko, Nishikido and Hitomi, Keitaro and Nogami, Satoshi and Kang, Hangyu and Taiga, Yamaya and Fumihiko, Nishikido and Kang, Hangyu and Taiga, Yamaya},
 month = {Oct},
 note = {TlBr is a high density (7.56 g/cm) semiconductor material composed of high effective atomic number elements. Therefore, TlBr has sufficient detection efficiency for 511 keV annihilation radiation in PET. In addition, TlBr detectors have high energy resolution due to the direct conversion to electrons. On the other hand, timing performance of typical semiconductor detectors is poor compared with scintillation detectors However, detection of Cerenkov light from TlBr offers an alternative method to get better timing resolution. This paper reports our feasibility study on the timing performance of TlBr detectors using Cerenkov light.
In the experiment, a conventional TlBr crystal and TlBr mixed with TlCl (TlBr-TlCl crystal) were used. The TlBr crystals were fabricated at Tohoku University. Each TlBr crystal was 3 × 3 × 3 mm3. The TlBr crystals were covered with ESR films and Teflon tape. Cerenkov light was detected with a multi-pixel photon counter (Hamamatsu S13360-3075CS). Coincidence detection measurement was carried out using a LYSO scintillator coupled with another MPPC (Hamamatsu S13360-3050CS) as a reference detector. Signals from the detectors were amplified with high frequency amplifiers and then waveforms were recorded with a digitizer (CAEN, DT5742). 
We obtained the timing spectra by Cerenkov light from the TlBr and scintillation light from the LYSO. From them, the timing resolution better than 600 ps was obtained for all the event data. After selecting the events by optimizing a trigger level, the timing resolutions better than 450 ps was obtained for both the TlBr detector and the TlBr-TlCl detector., 2021 Virtual IEEE Nuclear science symposium and medical imaging conference},
 title = {Timing resolution of TlBr and TlBr-TlCl PET detectors based on Cerenkov radiation measurement},
 year = {2021}
}