Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2018 Impact factor 0.961

Nuclear Science and Techniques ›› 2008, Vol. 19 ›› Issue (6): 358-364

• ADVANCED NUCLEAR INSTRUMENTATION AND DETECTION • Previous Articles     Next Articles

Method for converting in-situ gamma ray spectra of a portable Ge detector to an incident photon flux energy distribution based on Monte Carlo simulation

Boubaker ASKRI1, ????Adel TRABELSI1, 2???Brahim BACCARI1   

  1. 1Unité de Physique Nucléaire et des Hautes énergies, Faculté des Sciences de Tunis, 2092 Tunis, Tunisia 2 Centre National de Sciences et de Technologies Nucléaires, Sidi Thabet, Tunisia
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Boubaker ASKRI, Adel TRABELSI, Brahim BACCARI. Method for converting in-situ gamma ray spectra of a portable Ge detector to an incident photon flux energy distribution based on Monte Carlo simulation.Nuclear Science and Techniques, 2008, 19(6): 358-364

Abstract:

A matrix stripping method for the conversion of in-situ gamma ray spectrum, obtained with portable Ge detector, to photon flux energy distribution is proposed. The detector response is fully described by its stripping matrix and full absorption efficiency curve. A charge collection efficiency function is introduced in the simulation to take into account the existence of a transition zone of increasing charge collection after the inactive Ge layer. Good agreement is obtained between simulated and experimental full absorption efficiencies. The characteristic stripping matrix is determined by Monte Carlo simulation for different incident photon energies using the Geant4 toolkit system. The photon flux energy distribution is deduced by stripping the measured spectrum of the partial absorption and cosmic ray events and then applying the full absorption efficiency curve. The stripping method is applied to a measured in-situ spectrum. The value of the absorbed dose rate in air deduced from the corresponding flux energy distribution agrees well with the value measured directly in-situ.

Key words: Monte Carlo simulation, Ge detector, Gamma radiation, Geant4, Stripping