P-i-n junction radiation may be used for the detection, measurement, and dosimetry of ionizing radiations. Sensitivity /unit volume is considerably increased over gas-phase devices. Such structures in silicon may be used to measure radiation in various ways. First, a high reverse potential can be applied to sweep out the radiation-generated carriers in a single pulse and the number of pulses counted. Second, the potential built up across the junction by radiation-generated carriers can be measured either as an open-circuit voltage or as a short-circuit current. Third, the current consisting of radiation-generated carriers can be measured with a galvanometer and collected under a strong electric field with the thermally generated carrier component balanced out potentiometrically. Use of these techniques allows measurements to be made in the dose rate ranges of 10 / to 104 R/min. Maximum sensitivity in use is achieved through pulse counting at the expense of a complex electronic equipment setup. Measurement of the open-circuit voltage is the simplest method of use. It is particularly useful for in vivo studies, clinical research, or animal experimentation.