Preparation of Beta-ray Calibration Sources for Estimating Tissue Doses from Skin Contamination

Abstract A new type of β-ray calibration source was designed for estimating tissue doses from skin contamination. Thin polyethylene ion-exchange membranes were applied for the source preparation. The method of determining tissue absorbed dose rates with an extrapolation chamber was discussed for the calibration sources prepared with 147Pm, 204TI and 90Sr-90Y. The influence of backscattered β-rays by source mount materials was estimated as a function of membrane source thickness. The membrane sources are quite suitable for the present purpose, because they have large uniform radioactive areas and can be easily handled without radioactive contamination.