Dual time-over-threshold: estimation of decay time and pulse height for scintillation detectors

To linearly estimate the decay time and pulse height of a scintillation detector with low power consumption, a dual time-over-threshold (dual-ToT) method is proposed in this paper. The results of comparative experiments conducted using a 3× 3× 3 mm³ LYSO crystal and 3× 3 mm² MPPC with 50 μm cells indicated that the resolution of the estimated decay time using the dual-ToT method was 3.8 ns standard deviation (SD), whereas 3.5 ns SD was obtained using fully digitized waveforms. Additionally, a linear relationship between the dual-ToT-based and the analog-to-digital converter (ADC)-based pulse height was successfully observed. The estimated pulse height resolution using the dual-ToT method and post analysis technique was 12–13% FWHM at 511 keV, which is comparable to that of the ADC-based measurement. These capabilities potentially indicate that the dual-ToT method could be an alternative to the ADC method, with the advantage of lower power consumption and being applicable to the phoswich detector and particle identification applications.