Experimental Verification of Bremsstrahlung Dosimetry Predictions for 0.75 MeV Electrons

摘要

Bremsstrahlung dose in CaF sub 2 TLDs from the radiation produced by 0.75 MeV electrons incident on Ta/C targets is measured and compared with that calculated via the CYLTRAN Monte Carlo code. The comparison was made to validate the code, which is used to predict and analyze radiation environments of flash x-ray simulators measured by TLDs. Over a wide range of Ta target thicknesses and radiation angles, the code is found to agree with the 5% measurements. For Ta thickness near those that optimize the radiation output, however, the code overestimates the radiation dose at small angles. Maximum overprediction is about 14 +- 5%. The general agreement, nonetheless, gives us confidence that the TLD calibration procedure is satisfactory and that the code performs well at this energy. For the bulk of the measurements, a standard TLD employing a 2.2 mm thick Al equilibrator was used. In this paper, we also show that this thickness can significantly attenuate the free-field dose and introduce significant photon buildup in the equilibrator. (ERA citation 12:014085)