A new method for post-acquisition correction of spectral distortion due to pulse pileup

The times between pulses generated by a radiation detector are known as the interarrival times. When the pulse amplitudes are sorted by an analog-to-digital converter (ADC) to produce a radiation energy spectrum, a minimum interarrival time is required for the ADC to make an error-free conversion. This is dependent on the pulse shape and duration, among other factors. When interarrival times are less than this minimum, either the event is recorded as a partial or total sum of two or more pulses, or one or more pulses are ignored altogether. The phenomenon of chance summing of pulses is known as pulse pileup and causes a distortion of the acquired spectrum which becomes more severe as the incoming count rate increases. A computation algorithm was described by Q. Bristow and R.G. Harrison (1991) for the correction of spectral distortion due to pulse pileup. The author demonstrated the application of the algorithm in the correction of high-count-rate spectra acquired from a 10×10×40 cm scintillation crystal for pulse pileup