Interpolation of the gamma spectrometer response function by means of spline method

A modified interpolation method is described for determining gamma-spectrometer response functions. The interpolation points have been chosen in accordance with the amplitude distributions of the gamma-radiation spectra. The number of regions and the form of response function in each of these depends largely on the spectrometer type and the gamma-quanta energy range in question. The interpolation of the response functions is effected by a two-step spline method. First, the boundaries of the characteristic amplitude regions are drawn and the numbers of channels-boundaries of the characteristic regions of gamma-quantum energies are determined in the energy-channel number plane by the spline method. The second step is the interpolation by cubic splines of the response function values in the characteristic regions. This method has been realized on a computer by ALGOL language. For illustration, the interpolation of the response function of a NaJ(Tl)-crystal scintillation gamma-spectrometer is considered. The results show that the interpolation error is 4% over the whole range, and 2% in the photopeak region