[Dosage measurement of fast electrons using modified Fricke's solution]

A combination of two different modifications indicated in the literature about the ferrosulfate dosimetry has been given. This permits a dose measurement which shows compared to the usual dosimetry of Fricke above all following advantages: dose specification related to water; displacement of the absorption maximum in the perceptible spectral sphere; increase of the sensibility and lower influence of pollutions. The molar coefficient of extinction of the modified solution has been determined from Co-60-gamma irradiation and is epsilonm = 1,46 - 10(4) L - Mol(-1) - cm(-1). The increase of extinction which has been measured with this method after the irradiation with 18 MeV electrons occurs linearly within the studied region to 1200 rd at least, the G-value is 15,5. The indicated method renders possible a relative simple calibration of the ionisation chambers which have been used in the practice.