Experimental study on neutron response of electronic personal dosimeters based on simulated workplace neutron field

BackgroundNeutron dose measurement faces challenges due to the wide range of neutron energy and the complexity of energy response. The response of electronic neutron personal dosimeters (n-EPDs) varies significantly under different energy spectra, and calibration with isotope neutron sources may lead to on-site dose measurement deviations.PurposeThis study aims to investigate the influences of neutron energy spectrum distribution and incident direction on the response of n-EPDs.MethodsFirstly, 252Cf isotope neutron source, D-T accelerator neutron source and materials such as heavy water, tungsten, iron, graphite and polyethylene, were used to establish four neutron radiation fields with different energy spectra. Then, the Bonner neutron spectrometer was employed to measure neutron energy spectra, while the incident angle distributions were calculated using Monte Carlo method. Finally, the response differences of two commercial electric personal neutron dosimeters (n-EPDs) were experimentally tested.ResultsThe relative deviation between measured spectrum and standard spectrum of 252Cf reference radiation field is within ±10% in the main energy regions. For four neutron fields, the fluence-averaged neutron energy ranges from 0.12 MeV to 2.00 MeV, the dose-averaged neutron energy ranges from 0.75 MeV to 3.65 MeV, and the spectra-averaged conversion coefficient ranges from 51.17 pSv·cm2 to 390.3 pSv·cm2. The maximum response differences of two commercial n-EPDs to four neutron fields are 5.7 and 6.7 times, respectively.ConclusionsResults of this study indicate that when using isotope neutron sources for calibration, n-EPDs readings often overestimate the actual individual dose equivalent in workplace, hence special attentions need to be paid to the impacts of energy response, neutron energy spectrum, and incident direction on measurement accuracy.