Radiation Characterization Analysis of Pushbroom Longwave Infrared Imaging Spectrometer

摘要

Noise equivalent temperature difference (NETD) is the key parameter characterizing the detectivity of infrared systems. Our developed pushbroom longwave infrared imaging spectrometer works in a waveband between 8μm to 10.5 μm. Its temperature sensitivity property is not only affected by atmosphere attenuation, transmittance of the optical system and the characteristics of electric circuit, but also restricted by the self-radiation. The NETD accurate calculation formula is derived according to its definition. Radiation analysis model of a pushbroom image spectrometer is set up, and its self-radiation is analyzed and calculated at different temperatures, such as 300K, 150K and 120K. Based on the obtained accurate formula, the relationships between the NETD of imaging spectrometer and atmospheric attenuation, F-number, effective pixel area of detector, equivalent noise bandwidth and CCD detectivity are analyzed in detail, and self-radiation is particularly discussed. The work we have done is to provide the basis for parameters determination in spectrometer system.