Optimal digital filtering in Gamma-ray spectroscopy

Abstract

In this paper, we address the subject of the digital nuclear spectroscopy as seen as a counterpart of the classic analogue approach. Consequently, we will present the design as well as the implementation on a DSP board, of the various necessary digital pulse processing techniques via digital filtering in order to provide the principal tasks which often take place in a generic “Gamma” digital spectroscopic setup. The first part will be devoted to the design of the digital IIR filter used for the charge preamplifier's slow-pole compensation. This will be followed by the practical estimation of the power spectral density relating to the electrical noise components present at the spectrometer's input. Thereafter, a very detailed attention will be given to the design of the digital optimal filter to be used for the charge measurements. We follow by another FIR filter, this one deals with the digital estimation of the reference line of measurements and then to achieve the role of the: Base Line Restorer. Lastly, we give a hardware implementation of the designed filters on the board: “TMS320C6713-DSK”, a DSP KIT developed by “DIGITAL Spectrum”.