Responses of LiF TLD in Different Media and Cavity Ionization Theory for Low Energy Photons below 200 keV
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Calculated photon responses of LiF TLDs based on Burlin's cavity theory were compared with those measured using the TLDs sandwiched between two Teflon, aluminum, copper and gold foils for 30 to 200keV X-rays. The discrepancies between the calculations and the measurements were within 48% for gold, while 15% for the other media. In the cavity theory, the weighting factors related to the electron attenuation are used. The factors differed largely from those calculated with a Monte Carlo transport code ITS, of which the validity was confirmed by comparison with the response measurements. The ITS calculations also showed that the attenuation coefficients of electrons from the foils did not necessarily agree with those from the cavity theory, and the coefficients largely depended on the media. To obtain the more accurate response easily, another method are proposed, noticing that the electrons incident on the LiF are absorbed completely below 200keV. In the new method, total dose in LiF is calculated using energy transmission and reflection coefficients for the dose given by the electrons from the foils and using the mass energy absorption coefficients for the dose by the electrons generated in LiF. Responses calculated with this method agreed with those of the ITS within a difference of 6%.
- Journal of Nuclear Science and Technology
Journal of Nuclear Science and Technology 34(2), 137-147, 1997-02-25
Atomic Energy Society of Japan