Fat'yanov O V, Asimow P D
Division of Geological and Planetary Sciences 252-21, California Institute of Technology, Pasadena, California 91125, USA.
Rev Sci Instrum. 2015 Oct;86(10):101502. doi: 10.1063/1.4932578.
We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30,000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen irradiance standard lamp.
我们描述了一种用于多通道光学高温计的精确校准程序，例如加州理工学院实验地球物理实验室使用的具有6通道、3纳秒时间分辨率的仪器。我们首先回顾了3000 - 30000K范围内冲击温度的校准源。高功率、盘绕式卤钨光谱辐照度标准似乎是可溯源至美国国家标准与技术研究院（NIST）的钨带灯的唯一实际替代方案，而现在已无法获得足够大校准面积的钨带灯。然而，辐射不均匀性使得使用这种盘绕式灯对采用成像或中继光学器件的高温计进行可靠且可重复的校准变得复杂。对已记录的冲击高温计校准至盘绕式辐照度标准灯的方法进行仔细分析表明，只有一种技术（在我们的情况下不能直接应用）没有重大的辐射测量误差。我们详细描述了改进后的加州理工学院高温计仪器及其绝对光谱辐照度校准程序，校准精度可达±5%。我们使用盘绕式卤钨灯灯丝经0.7倍缩小的图像中的指定中心区域，并与可溯源至NIST的钨带灯进行交叉校准。我们给出了交叉校准的结果以及光学布置、数据采集和处理的描述。我们描述了一种表征放大光电探测器静态和动态响应差异的程序，从而得到用于冲击实验光谱辐照度历史的随时间变化的光电二极管校正因子。我们通过对单晶NaCl和MgO进行实际冲击温度实验验证了改进后的加州理工学院高温计的正确运行，并与这些物质的文献数据取得了很好的一致性。我们最后总结了使用高功率盘绕式卤钨辐照度标准灯对光纤冲击温度高温计进行无误差校准的最基本要求。
