A process and device for generating a prototype waveform and a weighting function. The process including obtaining waveforms generated by a detector having at least one photosensor, generating an initial estimate for the prototype waveform and the weighting function and parameterizing the prototype waveform and the weighting function and determining for each waveform an optimal amplitude and an optimal time offset of the prototype waveform. Included are steps of pairing waveforms based on the determined time offsets of the waveforms, calculating an arrival time difference for each pair of waveforms and determining a timing resolution value based on the calculated arrival time differences, determining whether the timing resolution value meets predetermined minimization criteria, and updating the set of parameters for the prototype waveform and the weighting function and repeating the determining, pairing, calculating, and determining, when the timing resolution value fails to meet the predetermined minimization criteria.