Dosimeter esp. for personal radiation exposure - has electrets to generate internal electrical field and background signal compensation

摘要

The parent patent describes a dosimeter, in which gas-filled chambers contain an electrical field produced by electrets; the ionising radiation to be measured produces charge pairs in these chambers and these charge pairs are sepd. by the electrical field. Equipment is also provided for measuring the electrical charge. In this addition the device comprises two ionisation chambers, sepd. by a movable electret disposed between two electrodes; the respective distances between these two electrodes and the electret are variable; the charge flowing from one electrode to the other via an interconnecting line as the electret is moved is used for the purpose of determining the distance between the ions charges produced in the two ionisation chambers and thus for evaluating the radiation dose to be measured. Used partic. for monitoring persons subject to radiation in laboratory work or nuclear power plants. The background signal produced by the electret charge can be eliminated, thus reducing the min. threshold of the measuring range achievable by the instrument.