Method and device for acquiring time point where glimmering pulse passes over threshold

A method for acquiring a time point when a scintillation pulse passes over a threshold, comprising:

• converting a relationship between the scintillation pulse and a set threshold into level signals by a comparator, wherein high-level signals are outputted in a case that an amplitude of the scintillation pulse is higher than the set threshold, or low-level signals are outputted in a case that the amplitude of the scintillation pulse is lower than the set threshold;
• segmenting the outputted high or low level signals, wherein a positive-going scintillation pulse is segmented into five phases:
• a first phase where the scintillation pulse is lower than the set threshold, a second phase where the scintillation pulse passes over and is higher than the set threshold, a third phase where the scintillation pulse is higher than the set threshold, a fourth phase where the scintillation pulse passes over and is lower than the set threshold and a fifth phase where the scintillation pulse is lower than the set threshold, of which the five phases occur sequentially;
• a negative-going scintillation pulse is segmented into five phases:
• a first phase where the scintillation pulse is higher than the set threshold, a second phase where the scintillation pulse passes over and is lower than the set threshold, a third phase where the scintillation pulse is lower than the set threshold, a fourth phase where the scintillation pulse passes over and is higher than the set threshold and a fifth phase where the scintillation pulse is higher than the set threshold, of which the five phases occur sequentially;
• and
• recording the time point when the scintillation pulse passes over the set threshold,
• wherein no time point when the scintillation pulse passes over the set threshold is recorded and the comparator outputs constant high-level signals or constant low-level signals during a phase of the five phases where the scintillation pulse is lower than the set threshold, and a phase of the five phases where the scintillation pulse is higher than the set threshold in a case that the scintillation pulse is the positive-going scintillation pulse or the negative-going scintillation pulse;
• during the second phase where the scintillation pulse passes over and is higher than the set threshold, N transitions occur at N time points, one of the N time points, or a median value or a weighted value of any two or more of the N time points is recorded as the time point when the scintillation pulse passes over the set threshold;
• during the fourth phase where the scintillation pulse passes over and is lower than the set threshold, M transitions occur at M time points, any one of the M time points, or a median value or a weighted value of any two or more of the M time points is recorded as the time point when the scintillation pulse passes over the set threshold, in a case that the scintillation pulse is the positive-going scintillation pulse;
• and
• during the second phase where the scintillation pulse passes over and is lower than the set threshold, P transitions occur at P time points, any one of the P time points, or a median value or a weighted value of any two or more of the P time points is recorded as the time point when the scintillation pulse passes over the set threshold;
• and during the fourth phase where the scintillation pulse passes over and is higher than the set threshold, S transitions occur at S time points, any one of the S time points, or a median value or a weighted value of any two or more of the S time points is recorded as the time point when the scintillation pulse passes over the set threshold, in a case that the scintillation pulse is the negative-going scintillation pulse.