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, ²⁰⁴Tl 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.