NAAPRO detector model, a versatile and efficient approach to gamma-ray spectrum simulation

摘要

The paper describes a detector model which is used by the Neutron Activation Analysis PRognosis and Optimization (NAAPRO) code for modeling gamma-ray spectra of the activation products generated by neutron irradiation of hypothetical multielement samples with user-specified composition. Distinctive features of the model are its sufficiently high productivity, flexibility and accuracy, which allow quickly obtaining a model gamma-spectrum for a complex energy composition of incident photon flux and arbitrary geometrical dimensions of scintillation (NaI, BGO) or HPGe crystals in a wide continuous range of the detection efficiency (epsilon(r) = 4-250%). Spectrum modeling is carried out based on the physically grounded efficient interpolation schemes for the full-energy peak, single- and double-escape peak efficiencies (as well as for Compton continuum distributions) which were calculated with the use of MCNP (a general purpose Monte Carlo N-Particle transport code) for a wide range of gamma-ray energies (5-4 MeV) and distances between source and detector. The influence of scattered photons, of additional absorbing filters, as well as of background conditions during measurement is taken into account in spectrum modeling. (c) 2006 Elsevier B.V. All rights reserved.