IDEA #1JZMLZ Equivalent Doze Dosimeter For Gamma And Neutron Radiation

APPLIED RESEARCH • SENSORSEQUIVALENT DOZE DOSIMETER FOR GAMMA AND NEUTRON RADIATION Description The breadboard model (prototype) of a dosimeter is developed for simultaneous measurement of an equivalent doze of small streams gamma and neutron radiation. The dosimeter is constructed in the form of scintillation spec(cid:2) trometer with two channels of registration. Each of the chan(cid:2) nels has the detector of radiation and an amplifying path. The analyzing part of a dosimeter including the analog(cid:2)digital con(cid:2) verter is common for two channels of registration. All units of the dosimeter (detectors, electronic units, the display and the keyboard) are placed in one case executed from polystyrene. Definition of a doze is carried out after processing the spectra which have been saved up simultaneously from two channels of registration. One channel (with the detector on the basis of inorganic scintillator) is intended for registration of gamma(cid:2) radiation. The second channel (with the detector on the basis of organic scintillator) is intended for registration of gamma(cid:2) radiation and fast neutrons. The next parameters are defined from inorganic scintillator spectrum: 1) structure of gamma(cid:2)radiation acting on a dosimeter; 2) an equivalent doze of gamma(cid:2)radiation; 3) the gamma(cid:2)radiation contribution in a spectrum registered by organic scintillator. The doze of fast neutrons is defined from a spectrum received in organic scintillator, minus the found gamma(cid:2)radiation con(cid:2) tribution. The breadboard model allows to measure power of an equiva(cid:2) lent doze of gamma(cid:2)radiation from 0,1 mkSv/hour up to 100 mkSv/hour in energy range of 0.04 (cid:2) 4.5 MeV. The doze of fast neutrons may be measured in a energy range from 0,2 up to 14 MeМ, at use of plastic scintillator as the detector of the mixed radiation, and from 0,04 up to 10 MeV, at use of stylbene. In these energy ranges an equivalent doze power of fast neutrons from 0,1 mkSv/hour up to 200 mkSv/hour may be measured. Accuracy of doze calculation depends on number of the impulses registered in spectra. Sensitivity of the gamma(cid:2)radiation detector depends on a direction of radiation (the angle of falling radiation is meas(cid:2) ured from a normal to a plane of an entrance window of the detector), differently for different energy: 60 keV (00 (cid:2) 1; 900 (cid:2) 0,9; 1800 (cid:2) 0,6); 660 keV (00 (cid:2) 1; 900 (cid:2) 0,95; 1800 (cid:2) 0,7); 1250 keV (00 (cid:2) 1; 900 (cid:2) 0,95; 1800 (cid:2) 0,8). Angular dependence of organic scintillator sensitivity to radi(cid:2) ation of plutonium(cid:2)berillium neutron source is characterized as: (00 (cid:2) 1; 900 (cid:2) 0,7; 1800 (cid:2) 0,5). The detector ooff gamma(cid:2)(cid:2)radiation:: scintillator NaI (Tl) 20х20 mm The detector ooff the mixed radiation:: plastic scintillator 30х30 mm Dimensions: 170х170х65 mm Weight: 2 kg 56 Fig.1. Control of radioactive sources in their storage facilities. Innovative Aspect and Main Advantages • Simultaneous measurement of a neutron and gamma(cid:2)radi(cid:2) ation doze. • Small energy dependence of an equivalent doze measure(cid:2) ment accuracy. Areas ooff Application Safety of the atomic power station, the control of radioactive substances, including fissionable materials. Stage ooff Development Prototype available for testing Contact Details Contact person: Tarasov Volodimir Organization: Institute for scintillation materials National Academy of Science of Ukraine. Address: Lenina av. 60, Kharkiv, 61001, Ukraine Tel : +38 (057) 341 03 92 Fax : +38 (057) 340 44 74 E(cid:2)mail : tarasov@isc.kharkov.com