Million channel pulse height analyser through pseudo-random digital transformation

Abstract

In all nuclear spectroscopy experiments data are collected in the form as they come from the source. It would be very difficult and expensive to analyse such data in million-channel resolution. A new technique is developed in which data from experiments are first digitally transformed into a new form and then analysed 1). Digital transformation is applied on-line to each event (descriptor). Passing through a transformation box, each descriptor produces a pseudo-random address into which it is stored. Transformation comprehends a scattered multidimensional physical spectrum into a minimal space, enabling high speed, on-line, multidimensional, million-channel spectrometry. The paper describes the computer system, which operates as a mega-channel, transformation mode analyser. Experiments with a real and computer simulated spectra show a very short dead time and high efficiency of the memory utilisation of the system. Transformation can be realized by simple hardware between ADC's and computer, or as a part of a computer interrupt routine. Both solutions are described.