Abstract: This invention provides a method of measuring exposure to radiation, particularly x-rays, gamma rays and other forms of penetrating radiation. A dielectric body is provided and is equipped with a pair of electrodes on opposite sides thereof. In accordance with one procedure which may be called radiation induced thermally activated depolarization (RITAD), an electrostatic bias polarization is produced in the dielectric body, preferably by heating it to an elevated temperature, impressing a voltage between the electrodes to produce internal polarization in the body, and cooling the body while maintaining the voltage, so as to freeze in the bias polarization. The voltage is then removed, and the electrodes may be short circuited. The body is then exposed to the radiation to be measured. After such exposure, a current measuring circuit is established between the electrodes. The electrical currents in such circuit are observed and measured as the energy level of the body is raised, preferably by heating the body.