High-accuracy irradiance calibration of space UV remote sensing instrument (SURSI) from 160 to 250 nm in vacuum using a liquid nitrogen cooled device

摘要

A signal degradation feature in pre-launch irradiance calibration of space UV remote sensing instrument (SURSI) in vacuum has been identified. We discuss the possible degradation factors, degradation mechanisms and degradation rules, and then demonstrate that the irradiance degradation of the deuterium lamp as the calibration source is the significant cause of the signal degradation. A liquid nitrogen cooled device (LNCD) has been developed and the irradiance degradation is reduced to 1percent during the radiometric calibration. On the basis of this LNCD, a high-accuracy irradiance calibration of the SURSI in vacuum from 160 to 250 nm has been performed and the calibration uncertainty is +-4.5percent. Finally, the extraterrestrial solar spectrum from 170 to 250 nm measured by the SURSI is compared with the one derived from the NOAA-11 SBUV/2, showing an agreement of better than +-3.2percent.