Noise equivalent radiance calibration system for infrared Fourier spectrometer at low-temperature and vacuum environment

The equivalent noise radiance (NESR) of infrared Fourier spectrometer is not only a reflection of its ultimate detection ability to infrared target signal, but also a core technical index of instrument. Limited by the current technical conditions in China, there is no relevant capability of calibration system testing and specification verification yet. Based on the standard transmission method of infrared radiation metering devices at home and abroad, a scheme of NESR high-precision testing device was proposed. The traceability chain of this device was put forward, its overall structure and optical path were also described, while a suppression system with low-temperature and vacuum background was designed. This designing scheme of radiation source on infrared integrating sphere with wide dynamic range, equivalent optical path and vacuum cryogenic environment were introduced in detail. The proposed technical solution provides a basic reference for NESR high-precision measurement, which also supports the condition of NESR quantity traceability for Fourier spectrometer in China.