Experimental and Monte Carlo based study of different microdosimetric quantities at mixed radiation environments of nuclear reactor, reprocessing facility and D-D accelerator

Abstract

Personnel working in the environment of nuclear reactors, fuel reprocessing facilities, high energy accelerators get exposed to a mixed radiation field of electrons, photons, and neutrons with a wide range of energy and fluence. Performance evaluations of the passive personnel dosimeters in these mixed radiation environments require knowledge of the external dose contributed by different types of radiations having variation in their energy, etc. Tissue Equivalent Proportional Counters (TEPC), sensitive to a wide range of particles and energy (Linear Energy Transfer (LET) ∼ 0–1500 keV μm−1), is one of the standard reference detectors which can be used for the characterization of mixed radiation fields. In the present work, HAWK TEPC was used to evaluate different microdosimetric parameters such as dose mean lineal energy (ӯD), average quality factor (Ǭ), the contribution of gamma and neutron dose equivalents for the characterizations of the radiation fields inside in a nuclear research reactor hall, fuel reprocessing facility, D-D neutron beam facility, radionuclide source based neutron calibration facilities, etc. Measured results were compared with Monte Carlo simulated values using radiation transport code PHITS. TEPC measurement shows that the radiation work field around nuclear reactor facility is dominated by gamma rays with approximate ӯD and Ǭ of ∼42 keV μm−1 and ∼2.3, respectively. Whereas ӯD and Ǭ values for neutron dominated locations in fuel reprocessing facility are 82 keV μm−1 and 8.2, respectively. Ǭ values near thermal neutron beam line in research reactor are close to 1 due to (n, γ) reaction. For 2.54 MeV mono-energetic D-D neutron beam, measured and calculated dose mean lineal energies (ӯD) are 52.5 keV μm−1 and 59.6 keV μm−1, respectively, whereas corresponding Ǭ values are 11.23 and 13.01. Obtained values can be utilized to correlate the neutron and gamma dose equivalents measured by passive detectors used for personnel monitoring program to enhance confidence in the dosimetry.