Steve R. Domen

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Extensive experimental comparisons of calorimetric and ionometric measurements have been made that cover a broader range of electron energies and depths in graphite than previously reported. Electron beams of 15, 20, 25, 30, 40, and 50 MeV were used. Calorimetric absorbed-dose measurements and ionometric specific-charge measurements in air were compared in(More)
Some thermal properties of A-150 tissue-equivalent plastic have been determined. The results are: thermal diffusivity, 2.72 x 10(-3) cm2s-1 +/- 0.4%; specific heat, 1.72 J g-1 K-1 +/- 1.3%; and thermal conductivity, 5.3 x 10(-3) WK-1 cm-1 +/- 1.4%. The significance of the measurements for the design of a calorimeter core calibration heater is briefly(More)
In early 1998, three transfer ionization chambers were used to compare the air-kerma and absorbed-dose-to-water calibration factors measured by the National Research Council of Canada (NRCC) and the National Institute of Standards and Technology (NIST). The ratios between the NRCC and NIST calibration factors are 0.9950 and 1.0061 in the case of the(More)
Advantage was taken of the low thermal diffusivity of water and the imperviousness of polyethylene film to water to construct a calorimeter for directly measuring absorbed dose in that medium. An ultrasmall bead thermistor was sandwiched between two thin films stretched on polystyrene rings and immersed in an unregulated water bath. Ten cobalt-60(More)
To explain a difference of 0.5 % between the absorbed-dose standards of the National Institute of Standards and Technology (NIST) and the National Research Council of Canada (NRCC), Seuntjens et al. suggest the fault lies with the NIST water calorimeter being operated at 22 °C and the method with which the measurements were made. Their calculations show(More)
In the present investigation a liquid ionization chamber has been used as a transfer instrument for the quantity absorbed dose in water in a cobalt-60 gamma-ray beam. The characteristics of the liquid ionization chamber are described. The transferred dosimetric information has been compared with absorbed-dose determination using air-ionization-chamber(More)
A portable carbon calorimeter built at the National Bureau of Standards was used in a 19.5 GeV electron beam at the Stanford Linear Accelerator to measure absorbed dose. The dose measurements were normalized to a given number of incident electrons by monitoring the electron intensity with a transmission ion chamber previously calibrated against a(More)
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