At present, most Tokamak devices adopt non-contact temperature measurements for the first wall using an infrared thermometer. Tungsten is regarded as the most likely plasma-facing material, especially as the divertor target, in future Tokamka devices. Accordingly, it is important to obtain accurate emissivity of tungsten for accurate temperature measurement of the divertor target plate and ensuring steady operation of Tokamak devices. In this work, a set of emissivity measurement equipment with a self-designed double-wavelength colorimetric infrared thermometer is established, and a method of emissivity measurement based on double-wavelength colorimetry considering background radiation is proposed. The normal spectral emissivity of tungsten with wavelengths of 10.2 μm and 10.8 μm between 140 and 500℃ in the same working environment as the Tokamak devices is measured after calibrating the optical splitter and the infrared thermometer by using a blackbody furnace. The measurement results indicate that the normal spectral emissivity of tungsten ranges from 0.0936 to 0.1246 between 140 and 500℃ in a vacuum environment. The emissivity increases with the increase of temperature, and the relative increase rate is 33.12%. Finally, the uncertainty of the emissivity measurement results is calculated, which ranges from 0.0444 to 0.0767. The normal spectral emissivity of tungsten measured based on the double-wavelength colorimetric principle proposed in this paper provides a good reference for the accurate temperature measurement of the divertor target plate in Tokamak devices. It also provides a reference for the measurement of metal emissivity with background radiation under similar vacuum conditions.

目前，大多数托卡马克装置采用红外测温仪对第一壁进行非接触式测温。在未来的托卡姆卡装置中，钨被认为是最有可能面向等离子体的材料，尤其是作为偏滤器目标。因此，获得准确的钨发射率对于偏滤器靶板的准确温度测量和确保托卡马克装置的稳定运行非常重要。在这项工作中，建立了一套带有自行设计的双波长比色红外测温仪的发射率测量设备，并提出了一种基于双波长比色法考虑背景辐射的发射率测量方法。钨的法向光谱发射率，波长为 10.2 μm 和 10。在使用黑体炉校准分光器和红外测温仪后，在与托卡马克装置相同的工作环境下，在 140 至 500℃ 之间测量 8 μm。测量结果表明，在真空环境中，钨的正常光谱发射率在 140 至 500 ℃ 之间为 0.0936 至 0.1246。发射率随着温度的升高而增加，相对增加率为33.12%。最后，计算发射率测量结果的不确定度，其范围为 0.0444 至 0.0767。基于本文提出的双波长比色原理测得的钨的法向光谱发射率，为托卡马克装置偏滤器靶板的准确测温提供了很好的参考。