Spectrum-Averaged Kerma Factors for Reactor Dosimetry with Paired Ion Chambers.
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
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Neutron and gamma spectrum-averaged kerma factors SAKFs were calculated for four reference spectra and 18 configurations of the AFRRI TRIGA reactor for materials of interest in dosimetry applications. Reactor gamma SAKF ratios for tissue to carbon and for tissue to magnesium ion chamber wall materials gave average values or - 2 standard deviations of 1.13 or - 1 and 1.09 or - 3, respectively. For some reactor configurations, the gamma SAKF ratios were as much as 7.6 different from corresponding values for cobalt-60 gamma rays. Reactor neutron SAKF ratios for ICRU International Commission on Radiation Units and Measurements muscle to ion chamber gas materials were as follows TE tissue-equivalent gas, 0.983 or - 0.5 for all configurations carbon dioxide, 9.8 10 and argon, 71 or - 27. At depth in a phantom, the neutron SAKF for ICRU muscle differed substantially from the free-in-air value for the same reactor configuration. This finding suggests the need for more thorough spectrum determinations in anatomical phantoms and for more sophisticated dosimetric tools to better quantitate the dose deposition process.
- Nuclear Physics and Elementary Particle Physics