Implementation of a cusp-like for real-time digital pulse shaper in nuclear spectrometry

Pulse shaping, which improves signal-to-noise ratio excellently, has been extensively used in nuclear signal processing. This paper presents a cusp-like pulse-shaping technique developed through the recursive difference equation in time domain. It can be implemented in field programmable gate array hardware system. Another flat-topped cusp-like shaper is developed to optimize the time constant of pulse shaping and reduce the influence of ballistic deficit. The methods of both baseline restoration and pile-up rejection are described. The 137Cs energy spectra measured with the digital cusp-like shaper are 6.6% energy resolution, while those by traditional analog pulse shaper are 7.2% energy resolution, under the same conditions. This technique offers flexibility, too, in adjusting the pulse shaper parameters.