Radiation dosimetry with zener diode

Commercially available zener diodes have been tested for applying them to dosimetry of cobalt-60 γ-rays. The response observed, i.e. the relation between irradiated dose and radiation-induced change in the breakdown voltage of the zener diode, have shown good linearity under the conditions: 1. The diode is kept below 50 0C during irradiation. 2. Measurement of the change in the breakdown voltage were made at the liquid-nitrogen temperature. A typical diode of Toshiba 05Z18 has been found to be useful for measuring irradiation doses between 15.48 kC/kg (6 x 107 R) and 2.58 MC/kg (1 x 1010 R) with a fading less than 10 % till 1000 hours after irradiation. This method of dosimetry has been applied to the measurement of the spatial distributions of γ rays inside a basket-type cobalt-60 source, and reasonable results have been obtained. It can be concluded from the present experiment that the radiation-induced change in the breakdown voltage of the zener diode offers a convenient and inexpensive method of radiation dosimetry. (author)