| 主权项 |
1. 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 phase where the scintillation pulse is lower than the set threshold, a phase where the scintillation pulse passes over and is higher than the set threshold, a phase where the scintillation pulse is higher than the set threshold, a phase where the scintillation pulse passes over and is lower than the set threshold and a 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 phase where the scintillation pulse is higher than the set threshold, a phase where the scintillation pulse passes over and is lower than the set threshold, a phase where the scintillation pulse is lower than the set threshold, a phase where the scintillation pulse passes over and is higher than the set threshold and a 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 the phase where the scintillation pulse is lower than the set threshold and the phase 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 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 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 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 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. |
