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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:32 |
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Conference: Bucharest University Faculty of Physics 2010 Meeting
Section: Applied Nuclear Physics
Title:
On the possibility of testing the homogeneity of the radionuclide distribution in volume sources
Authors:
E. Stancu (1), R. Suvaila (2), O. Sima (1)
Affiliation:
(1) Faculty of Physics, University of Bucharest
(2) National Institute for Physics and Nuclear Engineering
IFIN-HH,
E-mail
elena_robu@hotmail.com
Keywords:
Gamma spectrometry, Volume source
Abstract:
In this work we investigate the possibility to observe non-homogeneity effects, if present, in gamma-ray emitting volume sources. To this aim a cylindrical 133Ba source was measured with the cylindrical surface in contact with the detector end cap in several equivalent positions, obtained by rotating the source around the symmetry axis. The spectra were collected in each position and the count rates in the peaks were evaluated. The spectrometry system included a high efficiency (47%) n-type HPGe detector, lead shielded, with LN2 purged inside the shield, a DSPEC Plus module and a PC. Standard software (Gamma Vision 32, version 6.04) was used for controlling the spectrometer and for the spectral analysis.In the case of a homogeneous source the count rate in the peak corresponding to a specific energy should be statistically the same in any position of the source. If there are departures from homogeneity, they should induce deviations in the count rates that we expect to be different in the case of normal gamma-ray peaks than in the case of pure sum peaks. Indeed, in the first case the efficiency is proportional with the solid angle while in the second it is roughly proportional with the square of the solid angle, so the two cases sample the inhomogeneities in a different way, the sum peaks being more sensitive to inhomogeneities. On the other hand, also the uncertainties of the count rates are different, so the statistical significance of the deviations is also different. Therefore it is interesting to test the homogeneity by using the count rate both from normal gamma-ray peaks and from pure sum peaks.
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