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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:51 |
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Conference: Bucharest University Faculty of Physics 2009 Meeting
Section: Nuclear and Elementary Particles Physics
Title:
Simulation of gamma-ray spectra for complex measurement systems using GEANT 3.21
Authors:
D. Radu1, O. Sima2
Affiliation:
1"Horia Hulubei" National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, P.O. Box MG-6, RO-0771256, Romania
2Physics department, Bucharest University, Bucharest-Magurele, P.O. Box MG-11, RO-077125, Romania
E-mail
radu.daniela@yahoo.co.uk
osima@olimp.fiz.infim.ro
Keywords:
Gamma-ray spectrometry; Monte Carlo simulation; Efficiency calibration
Abstract:
HPGe detectors are commonly used in gamma-ray spectrometry measurement systems where nuclide identification and also quantification are desired. For quantification, an efficiency calibration must be performed. This task becomes increasingly difficult and expensive as the sources become large and complex. This work relates to the study and characterization of the response function of two gamma-ray spectrometry systems: ISOCART (Ortec) and Segmented Gamma Scanner WS1100 (Canberra) used for measuring especially large sources. To this purpose the Monte Carlo code GEANT 3.21 was applied. In this code, the history of each source photon, as well as each secondary photon and electron resulting from interactions in the source, detector and the environment is followed until its energy becomes low enough for it to be considered locally absorbed. The total number of histories traced in each run must be large enough to obtain tallies with an acceptable uncertainty. A major advantage of this technique is the flexibility for describing accurately various experimental systems, including in our case a detailed characterization of the detector, collimator system and the complex, high volume, source. Using GEANT 3.21 the spectra expected in the photon energy range from 50 to 2000 keV for high volume sources measured with ISOCART and SGS-WS1100 were simulated. The full energy peak efficiency as well as the total efficiency were also evaluated.
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