Calculation of gamma energy spectrum from NaI(Tl) detector pulse height spectrum

The matrix method of solving the Fredholm integral equation for the deconvolution of the pulse height spectrum of a scintillation detector is described. The response function matrix for a 40 mm dia. by 40 mm thick NaI(Tl) detector was constructed from experimental response functions for a set of monoenergetic sources. The scintillation detector resolution was not taken into consideration. The angular dependence of the response function matrix is discussed. The suitability is discussed of the applied method of solving the integral equation with respect to the properties of the response function matrix