hi All, I have a question about the definition of the coincidence time window, which might be different among the GATE society and the nuclear electronics people. According to the GATE user's manual, the coincidence window is the width of the single pulse, however, according to some literature and electronics engineering people, the coincidence windows are defined as twice of the width of the single pulse. So if they say one PET camera has a coincidence window of 10 ns, this should mean that the width of the single pulse is 5 ns. If this is the case, then we should setup the coincidence window in GATE simulation as 5 ns rather than 10 ns. I've checked several published papers about the validation of the GATE, no one has made any comment on this issue explicitly. So I brought this to you attention and hope you can give some comments. Best regards, Yuxuan