On nuclear spectrometry pulses digital shaping and processing

Trapezoidal pulse shaping by a digital technique from nuclear spectrometry preamplifier output is reported. The shaping is especially suitable for tim e and/or pulse-height spectra measurements from high counting rate sources which commonly implies pulse pile up. In fact, piled up events may be ident ified and measured rather than rejected as in usual analog systems. Moreove r, the amplitude-arrival time measurement of piled up pulses by the trapezo idal shape is simpler than by both maximum likelihood and least squares est imators, or adaptive nonlinear least squares methods which give better resu lts in the case of severe pile up. Comparison with different techniques cur rently used in fast scanners for nuclear medicine studies is given. The tec hnique utility in high energy semiconductor gamma ray spectrometry is also discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.