Intercomparison of neutron personal dose equivalent measured by thermoluminescence dosimeters

An intercomparison of neutron personal dose equivalent measured by the Harshaw thermoluminescence neutron dosimeters (TLDs) between the National Institute of Metrology of China (NIM) and the Institute for Nuclear Science and Technology of Vietnam (INST) was performed. Three sets of TLDs (each set consisting of five TLDs) were prepared for each laboratory. Each set was then irradiated to the corresponding same nominal standard value of neutron personal dose equivalent, H_p(10)_n-stdⁱ, of 1.0, 2.0, and 3.0 mSv, respectively at these two laboratories. The irradiated TLDs were then read-out at the INST using the Harshaw 4500-type TLD reader to obtain neutron personal dose equivalents at the NIM, H_p(10)_n-NIMⁱ and at the INST, H_p(10)_n-INSTⁱ, which are corresponding to different values of H_p(10)_n-stdⁱ. The TLDs' responses to different scattered components of neutrons in these two fields are also discussed. Comparisons between the corresponding pair values of H_p(10)_n-NIMⁱ and H_p(10)_n-INSTⁱ show good agreements within 10% with the standard uncertainty of 12.5% (k = 1). The measured values of H_p(10)_n-NIMⁱ and H_p(10)_n-INSTⁱ are satisfied the Trumpet curve criteria. This implies that the TLDs can be used for safety assessment of occupational neutron personal dose equivalents. This intercomparison result also confirms the capabilities of these two laboratories (i.e., NIM, INST) on deliveries of neutron personal dose equivalent standard values for calibrations.