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Article
Ionization efficiencies of alanine dosimeters and tooth enamel irradiated by gamma and X-ray sources
Radiation Measurements
  • Rainer Grün, The Australian National University
  • Rosli Mahat, University of Malaya
  • Renaud Joannes-Boyau, Southern Cross University
Document Type
Article
Publication Date
1-1-2012
Peer Reviewed
Peer-Reviewed
Abstract
The relative ionisation efficiencies of alanine dosimeters and tooth enamel differ greatly between gamma and X-ray irradiations. This can be attributed to the differences in the energy transfer mechanisms. When using Co or Cs sources, the photon energy is transferred to matter via Compton scattering, which shows little dependence on the average Z-value of the absorber. In contrast, the photon energies emitted from X-ray sources are usually much lower and energy is, at least in part, transferred to matter via the photo-electric effect, which has a cubic relationship between energy transfer and average Z-value of the absorber. The decomposition of the ESR spectra of an enamel fragment shows that the X-ray generated distribution of anisotropic radicals is virtually the same as in the natural sample, but quite different to gamma irradiated samples. This implies that X-rays are generally much better suited for ESR dating irradiation procedures than gamma rays. However, exact source calibration will be difficult.
Citation Information

Grün, R, Mahat, R & Joannes-Boyau, R 2012, 'Ionization efficiencies of alanine dosimeters and tooth enamel irradiated by gamma and X-ray sources', Radiation Measurements, vol. 47, no. 9, pp. 665-668.

Published version available from:

http://dx.doi.org/10.1016/j.radmeas.2012.03.018