Study of PMMA dosimeters response against storage temperature and post-irradiation time

Abstract

In ensuring the correct amount of the absorbed dose received, the proper treatment in dosimeter measurement is needed due to several factors that can affect the measurement results. Therefore, the observation focuses on the measurement results of the absorbed dose of type 3042 AA Harwell fabrication-PMMA dosimeter against storage temperature and post-irradiation time. The dosimeter is irradiated using Gamma Cell Upgrade 220 with a dose rate of 4,718 Gy/hour and a target dose of 10 kGy and 25 kGy. Irradiated dosimeters are treated with storage temperatures at 4℃, 23℃, and 40℃ and post-irradiation times at 0 hours, 1 hour, 1 day, 3 days and 7 days. The absorbed-dose measurements are compared with the calibration results of PMMA dosimeter with the Fricke standard. At the target dose of 10 kGy, it shows that the temperature of 23℃ has the smallest average error that is 5.76% with a 7-day measurement tolerance time. A similar thing happened at the target dose of 25 kGy, it has the smallest average error of 1.81%. However, the target dose of 25 kGy shows that dosimeter cannot be stored at 40℃ longer than 1 day due to error tolerance is reaching 46.09%.