Possible application of an imaging plate to space radiation dosimetry.
Fading correction plays an important role in the application of commercially available BaBrF:Eu2+ phosphors: imaging plates (IP) to dosimetry. We successfully determined a fading correction equation, which is a function of elapsed time and absolute temperature, as the sum of several exponentially decaying components having different half-lives. In this work, a new method was developed to eliminate a short half-life component by annealing the IP and estimating the radiation dose with the long half-life components. Annealing decreases the effect of fading on the estimated dose, however, it also causes the loss of photo-stimulated luminescence (PSL). Considering an IP as an integral detector for a specific period of up to one month, the practically optimum conditions for quantitative measurement with two types of IP (BAS-TR and BAS-MS) were evaluated by using the fading correction equation, which was obtained after irradiation with a 244Cm source as the alpha-ray source having a specific radioactivity of 1,638.5 Bq/cm2 including beta and gamma-ray (alpha energy of 5.763 and 5.805 MeV). Annealing at 80 degrees C for 24 hours after irradiation for one month using BAS-MS should minimize the effect of the elapsed time, resulting in sufficient sensitivity. The results demonstrate new possibilities for radiation dosimetry offered by the use of an IP.
Ohuchi
Hiroko
H
Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki-Aoba, Aoba-ku, Sendai 980-8578, Japan. hiroko@mail.pharm.tohoku.ac.jp
Yamadera
Akira
A
D003359:Cosmic Radiation; D003952:Diagnostic Imaging / Q000295:instrumentation*; D011874:Radiometry / Q000295:instrumentation*; D013696:Temperature; D013997:Time Factors