Monte Carlo study of reference photon fields in the irradiation halls of the Czech Metrology Institute

The MCNPX code was used to obtain characteristics of collimated photon beams from a 60Co source and a radiotherapy 60Co irradiator “Chisobalt 2 B75” was exploited for calibration and verification of dosimeters in the Czech Metrology Institute, Inspectorate for Ionizing Radiation (CMI-IIR; Czech metr...

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Bibliographic Details
Published inNuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 580; no. 1; pp. 141 - 144
Main Author Šolc, J.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 21.09.2007
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Summary:The MCNPX code was used to obtain characteristics of collimated photon beams from a 60Co source and a radiotherapy 60Co irradiator “Chisobalt 2 B75” was exploited for calibration and verification of dosimeters in the Czech Metrology Institute, Inspectorate for Ionizing Radiation (CMI-IIR; Czech metrology body). First, for each source, a longitudinal profile of air kerma rate on the beam axis and a transversal profile of air kerma rate at a distance of 1 m from the front of the source's collimator were simulated, and the results were compared with the experimental data obtained with ionization chambers. Measured and calculated data were in good agreement. Second, the number of scattered photons in the fluence spectra along and across the beam axes, and their contribution to air kerma were specified. Third, the individual contributions of photons scattered in collimator, air, floor, walls, mobile platform and other parts of the irradiation halls to the total air kerma rate on the beam axis were calculated for the purposes of future improvement of metrological parameters of photon beams in CMI-IIR.
ISSN:0168-9002
1872-9576
DOI:10.1016/j.nima.2007.05.054