Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Physical Chemistry

New developed pellet dosimeter based on radiation-sensitive element of 2-methyl alanine (2-MA) for radiation process control was manufactured and its dosimetric characteristics for high-dose range 1-100 kGy applications was investigated by EPR spectrometer. The EPR spectrum of irradiated 2-MA pellets exhibits an isotropic signal with seven lines. The dose response function has a linear trend in the range of 1-11.4 kGy and sub-linear in the range of 11.4-100 kGy. It is found also that the pellet dosimeters response has a negligible humidity effect during irradiation in the range of humidity from 33-76% RH. The average increase of response as a function of temperature rise (21-60 oC) during irradiation is ~0.96% /oC. The energy dependence of the manufactured dosimeter in the range of 0.1 {u2013} 15 MeV was calculated and it was nearly adipose tissue equivalent in this range. Additionally, it was found nearly water equivalent in the photon energy level of 0.15-4 MeV; however, out of this range, the variation from water equivalency is within 6%. The overall uncertainty of the measured doses was ~6.6% and ~4.5% (2v, 95% confidence level) for the dose ranges of 1-11.4 kGy and 11.4-100 kGy, respectively

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