In this paper, the performance of the low-level gamma-ray spectrometry systems at UDO will be described. It focuses on technical aspects and the experiences gained after changes and improvements of the most sensitive detector had been performed.
3. On Monte Carlo Simulation of HPGE Gamma-Spectrometry Systems
Abstract: A complete calibration of gamma-spectrometry systems cannot be achieved exclu-sively on the basis of experimental measurements. Comprehensive experimental calibration is especially difficult in the case of low-level measurements, when volume sources, for which a proper standard is unavailable, are measured in close to detector high efficiency configura-tions, favoring important nuclide specific coincidence-summing effects. In such cases Monte Carlo simulation methods are among the best tools available for complementing experimen-tal calibration.
A recent intercomparison of Monte Carlo codes used in gamma-ray spectrometry revealed surprising differences between the results of different codes . In this work our experience in using GESPECOR and GEANT 3.21 to solve problems in gamma-ray spectrometry (with emphasis on low-level measurements) is reviewed. The focus is on the problems resulting from differences between the two codes. Several topics related to the physics database, to the simulation parameters and algorithms and to problem definition are discussed.
Differences in interaction cross sections applied in the two programs are pointed out and the consequences on the simulation results in various measurement configurations are dis-cussed.
|Contact: Dr. Dirk Arnold|
Physikalisch-Technische Bundesanstalt (PTB)