ORIGINAL ARTICLE |
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Year : 2015 | Volume
: 38
| Issue : 4 | Page : 130-134 |
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Validation of analytical functions to fit detection efficiencies of NaI(Tl) scintillation detector in the energy range of 122–1332 keV
L Thilagam, MR Priya, DK Mohapatra
Nuclear Safety Analysis Section, Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam, Tamilnadu, India
Correspondence Address:
L Thilagam Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam - 603 102, Tamil Nadu India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0972-0464.176154
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Various analytical functions proposed to express the full energy photopeak efficiency (FEPE) of gamma ray detectors have been investigated for their performance to fit the percentage FEPE of Amcrys-H made 2” × 2” NaI(Tl) scintillation detector. Initially, the experimental measurements on FEPEs of various gamma sources were used to validate the theoretical Monte Carlo (MC) simulations. The maximum deviation observed between the experimental efficiencies and MC simulations is -12.51%, which is observed for 356 keV of 133Ba. The percentage FEPEs obtained through validated MC simulations are then fitted against gamma energy in the range 122–1332 keV using the recommended efficiency functions to obtain the percentage FEPE as a smooth function of gamma energy for the source to detector distance of 5 cm. The analytical function recommended by McNelles, Campbell and Singh is identified as the most suitable for the detector type considered and this, in turn, is used to obtain fitting coefficients for all other source to detector distances. The fitted equations are found to provide the percentage FEPEs, which are well within ±6% deviation with respect to the theoretical MC simulations for most of the energies and distances. For the source to detector distances of 15 and 25 cm, the gamma energy of 500 keV is found to have the maximum deviations up to 7.6%. |
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