DOSAGE EQUIVALENT AND IRRADIATION DOSAGE MEASURING INSTRUMENT

摘要

PURPOSE:To easily change by one instrument between the measurement of various dosage equivalents before the revision of the law and the measurement of an irradia tion dosage before the revision by applying or stopping a voltage to a compensation ionization part by the switching of a voltage applying circuit. CONSTITUTION:A measurement ionization part 10 has an incidence window 14a for radiation measurement and applies a specific voltage to collect ionized charges to a current collecting electrode 18a. Further, the compensation ionization part 12 with specific-volume-ratio capacity which is formed at a position opposite the reverse surface of the incidence window 14a of the ionization part 10 has an application electrode 16 with the opposite polarity from the application electrode 14 of the ionization part 10 and the collecting electrode 18a limits the transmission of radiation. Then a partition plate 18 between the ionization parts 10 and 12 absorbs radiation incident on the ionization part 12 and an electrometer 20 connected to the collecting electrode 18a between the ionization parts 10 and 12 measures a collected current corresponding to an incidence dosage. Then the voltage applying circuit is switched to measure the dosage equivalent or irradiation dosage optionally according to whether or not the electrode 16 of the ionization part 12 is applied with the voltage having the oppo site polarity.