Publications by authors named "Nobuhisa Takata"
Effect of the diaphragm of free-air ionisation chamber for X-ray air-kerma measurements.
Radiat Prot Dosimetry
July 2011
Article Synopsis
- Free-air ionisation chambers are critical at standards laboratories for accurately measuring air kerma in X-ray fields.
- The diaphragm aperture size in these chambers is vital as it affects the X-ray beam size that interacts with the chamber.
- This study utilizes Monte Carlo simulation to determine correction factors for X-ray transmission and scatter affecting measurements of different-sized free-air ionisation chambers at various X-ray energies and distances.
[Air kerma standards for X- and gamma rays and future plans for dosimetric standards at AIST].
Nihon Hoshasen Gijutsu Gakkai Zasshi
August 2006
The dependence of the results of air kerma measurements on the orientation of the cylindrical cavity chamber used for beam standardizations is reexamined. The wall attenuation correction factors for the (60)Co and (136)Cs air kerma measurements were obtained for various irradiation angles by extrapolation of the dependences of experimental data and by Monte Carlo simulations. Applying the correction based on extrapolation does not provide an angle-invariant air kerma rate, as desired.
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