A new digital filter based on sinusoidal function for gamma spectroscopy

Abstract A novel digital filter (sin filter) based on sinusoidal function was designed, described and evaluated in this paper. The mathematical model of sin filter was deduced and established in detail. Simulation and experiment were conducted for both sin and trapezoid filters to assess the former. Energy resolution for NaI (Tl) detector (CH282) was calculated, and the optimum resolution (@Cs137,662keV) after sin and trapezoid filter is 7.88% and 7.83%, respectively, which is 8.57% before filtering. The DC offset is totally restored and the baseline drift is completely restrained after sin filter. The results proved that sin filter achieves similar performance on noise suppression, immunity to ballistic deficit, pile-up reduction, baseline restoration and energy resolution improvement compared with trapezoid filter, while gains more simplicity, operability and flexibility. This paper gives a simpler digital filter for gamma spectroscopy.