Handheld X-ray fluorescence (HH-XRF) has expanded its utilization areas according to recent technological developments. Most current applications, though, are still concentrated in traditional areas including mineral resource analysis and environmental regulation rather than forensic science for the purpose of investigating a nuclear security event involving nuclear material out of regulatory control. To apply HH-XRF to nuclear material analysis, it is necessary to first obtain calibration data using standard reference materials. Considering the difficulty in obtaining such standard reference materials as well as the high costs involved, one well-known alternative method is to use Monte Carlo simulation code. This study investigated the feasibility of employing Monte Carlo N-Particle transport 6 (MCNP6) simulation to provide calibration data through comparison with experimental measurements of pure solid samples of graphite, copper, SiO₂, and UO₂ using HH-XRF. The results showed that the MCNP6 simulation results were entirely consistent with the measurement spectra, except for environmental interferences stemming from interactions with the mechanical components below 10 keV which varied slightly according to sample type. To quantitatively evaluate the effect of these environmental interferences on the whole spectrum, the coefficient of determination (R²) was used. In the case of graphite, the effect of the environmental interferences was evaluated to be about 20% on the conformity of the measured and simulated results, while those for copper, SiO₂, and UO₂ were about 1%, 3%, and less than 1%, respectively. These results indicate that samples having elements with higher rates of photoelectric absorption followed by fluorescence compared to scattering tend to decrease the effect of the environmental interferences over the entire spectrum. The origin of the environmental interferences was estimated to be interference with the detector shield and/or X-ray tube collimator, which are particular design features of the device used. Their effect on contributing to the environmental interferences was evaluated by experiment for the detector shield and simulation for the X-ray tube collimator. As the detector shield was found to only contribute to a decrease in overall spectrum intensity, the major contributor to the environmental interferences was determined to be the collimator. It is believed that the results of this study will help to confirm that Monte Carlo simulation can properly provide calibration data for using HH-XRF on nuclear materials for which reference materials are hard to obtain.

手持式X射线荧光（HH-XRF）根据最近的技术发展扩大了其使用范围。但是，当前大多数应用仍集中在传统领域，包括矿产资源分析和环境监管，而不是法医科学，目的是调查涉及核材料不受监管控制的核安全事件。要将HH-XRF应用于核材料分析，必须首先使用标准参考材料获得校准数据。考虑到获得这种标准参考材料的困难以及所涉及的高成本，一种众所周知的替代方法是使用蒙特卡洛模拟代码。₂和使用HH-XRF的UO ₂。结果表明，MCNP6模拟结果与测量光谱完全一致，除了与低于10 keV的机械组件相互作用而产生的环境干扰外，该干扰随样品类型的不同而略有不同。为了定量评估这些环境干扰对整个光谱的影响，使用了测定系数（R ²）。对于石墨，环境干扰对测量和模拟结果一致性的评估约为20％，而对于铜，SiO ₂和UO ₂则为分别约为1％，3％和小于1％。这些结果表明，与散射相比，具有更高光电吸收率的元素以及随后具有荧光性的元素的样品往往会降低整个光谱对环境干扰的影响。据估计，环境干扰的起因是对检测器护罩和/或X射线管准直器的干扰，这是所用设备的特殊设计特征。通过检测器屏蔽层的实验以及X射线管准直器的仿真评估了它们对环境干扰的影响。由于发现探测器的防护罩仅有助于降低整体频谱强度，因此确定对环境干扰的主要贡献者是准直仪。