Investigation of the Spectrophotometric Method of Measuring the Ferric Ion Yield in the Ferrous Sulfate Dosimeter

The sensitivity of the spectrophotometric method of measuring the ferric ion yield in the ferrous sulfate dosimeter was increased by measuring the absorbance of the radiation produced ferric ions at 224 m mu , instead of at 304 m mu . The higher sensitivity is due to the higher raolar extinction coefficient at 224 m mu which is 4565 liter mole/sup -1/ cm/sup -1/, compared with 2196 liter mole/sup -1/ cm/sup -1/ at 304 m mu . By this method, the measuring range of the ferrous sulfate dosimeter can be extended to smaller doses. The much smaller tcmperature dependence and smaller acidity dependence of the molar extinction coefficient at 224 m mu , compared with those observed at 304 m mu , increase the reproducibility of dose measurements. (auth)