Evaluation of a well-type ionization chamber for calibration of HDL and LDR brachytherapy sources

The Atomlab 44D well-type ionization chamber is being evaluated for calibration of high dose rate (HDR) Ir-192 and low dose rate (LDR) Cs-137 sources. The chamber has a flat response (sweet spot) of +/- 0.5% along approximately 3.5 cm for an Ir-192 HDR linear source and 3 cm for a Cs-137 LDR spherical source. The short-term stability of the chamber was determined using a cylindrical Cs-137 source positioned in the sweet spot region. The chamber response over a range of 17.4 mCi (644 MBq, Cs-137) and 8.82 Ci (326 GBq, Ir-192) is evaluated. The chamber may be used for calibrating the activities of both HDR Ir-192 and LDR brachytherapy sources.