关键词: β-γ混合辐射场, 定向剂量当量率$\dot{H}^{\prime}$(0.07), 周围剂量当量率$\dot{H}$^*(10), 校准因子修正

Abstract: To address the challenge of accurately determining the directional dose equivalent rate $\dot{H}^{\prime}$(0.07) in β-γ mixed radiation fields, a novel measurement methodology is proposed. This approach integrates measurements from ambient dose equivalent rate monitors, directional dose equivalent rate monitors, β spectrometers, and γ spectrometers. A β-γ mixed standard radiation field was established to verify this method.Following application of the methodology proposed in this study, the relative error between the measured $\dot{H}^{\prime}$(0.07, 45°) value and the reference value traceable to a certified standard instrument was reduced from 13.0% to 2.69%, verifying the method’s reliability.In field applications, $\dot{H}^{\prime}$(0.07) was measured and data were processed at 14 locations exposed to β-γ mixed radiation fields during the No.106 overhaul of Hainan nuclear power plant. The measured H·'(0.07)$\dot{H}$^*(10) ratios ranged from 2.06 to 29.1, with a mean value of 9.64—indicating that $\dot{H}^{\prime}$(0.07) was, on average, approximately one order of magnitude greater than $\dot{H}$^*(10). Accurate quantification of $\dot{H}^{\prime}$(0.07) in β-γ mixed fields is therefore essential for reliable assessment of occupational exposure risk and provides critical input for radiation protection decision-making in nuclear facilities.

Key words: β-γ mixed radiation field, directional dose equivalent rate $\dot{H}^{\prime}$(0.07);ambient dose equivalent rate $\dot{H}$^*(10), calibration factor correction