A Study of Background Subtraction Method for NaI(Tl) Instrument Spectrum Based on Adaptive FWHM

Abstract

How to effectively subtract the background is one of the key technologies of spectrum date analysis in the gamma-ray energy spectra measurements. The paper, according to the SNIP(Statistics Sensitive Nonlinear Iterative Peak-Clipping Algorithm) method that has many advantages on background subtraction in the full spectrum, elaborates the principles of improved SNIP algorithm and the process of background subtraction in detail. However, it is because of traditional SNIP algorithm when deducting the background that the parameter m value of transform window-width is difficult to be determined automatically, by analyzing characteristics of NaI(Tl) scintillation detector and the physical characteristics of forming spectra, the method for deducting the background based on SNIP of adaptive FWHM(The Full Width of the peak at Half Maximum) is proposed, which is used to solve the problems effectively on valuing the parameter m both automatically and accurately. Multiple sets of spectral data show that the improved SNIP method can correctly subtract the contributions of Compton scattering effect to spectra peak counts, weakens background counting of scattering peak, is simple, quick, easy for computer automatic processing, so these advantages have brought excellent results.