BRDF measurements of graphite used in high-temperature fixed point blackbody radiators: a multi-angle study at 405 nm and 658 nm
BRDF measurements of graphite used in high-temperature fixed point blackbody radiators: a multi-angle study at 405 nm and 658 nm
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高温定点黑体辐射器中使用的石墨的 BRDF 测量：405 nm 和 658 nm 的多角度研究
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
T. Germer
中科院分区：
文献类型：
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作者：
H. Patrick;L. Hanssen;J. Zeng;T. Germer
测量了用于制作高温定点黑体腔的两种石墨在入射面内外的偏振分辨双向反射分布函数(BRDF)。测量是在室温下用405 nm和658 nm的激光光源，样品的入射角从垂直入射到70°变化。所有样品都表现出非朗伯行为，包括在大入射角下的前向散射增强，特别是对S偏振入射光。非偏振入射光的方向半球形反射率是通过积分在样品上半球内各个点测量的BRDF而获得的，根据样品和入射角度的不同，从0.083到0.101不等。讨论了这些测量结果对石墨黑体辐射体发射率模型和辐射温度标度分布的潜在影响。
We have measured the polarization-resolved bidirectional reflectance distribution function (BRDF) for two types of graphite used in the fabrication of high-temperature fixed point blackbody cavities in and out of the plane of incidence. Measurements were made at room temperature using 405 nm and 658 nm laser sources, and the samples were illuminated at angles of incidence varying from normal incidence to 70°. All of the samples exhibited non-Lambertian behaviour, including enhanced forward scatter at high incident angles, especially for s-polarized incident light. The directional-hemispherical reflectance for unpolarized incident light, obtained by integrating the BRDF measured at individual points in a hemisphere over the sample, ranged from 0.083 to 0.101, depending upon sample and incident angle. The potential impact of these measurements on emissivity models for graphite blackbody radiators and radiance temperature scale dissemination is discussed.