NUCLEAR PULSE DISCRIMINATION USING STATISTICAL DETECTION THEORY

The introduction of modem materials, like HgI2, into the field of nucl ear detection is not fulfilling previous expectations. Due to technolo gical problems, a significant percentage of HgI2 detectors do not resp ond to the theoretical behaviour in the detection of radiation. This i s mainly the case when high efficiency is desired and thick detectors must be employed. In particular, standard discriminators are sensitive to evolution in time of the pulse parameters, such as amplitude or ri se time. This phenomenon has been related to polarization effects. In order to improve the response of these ''bad quality'' detectors, we h ave studied the possibility of using statistical discrimination method s implemented by means of digital processing techniques, aiming to kee p the counting behaviour stable in time when thick HgI2 detectors (1 c m) are employed. Some theoretical aspects of these procedures are pres ented and a discrimination algorithm is implemented with the help of a real-time fast digital processor.