Direct measurement of total emissivities at cryogenic temperatures: Application to satellite coatings

The Herve et al. design accommodated up to five samples simultaneously and utilized an electric mechanism to enable multi-angle measurements.

“The design accommodated up to five samples simultaneously and utilized an electric mechanism to enable multi-angle measurements.”

The Herve et al. system employed a refrigerator as the cold source and incorporated a diamond window, enabling emissivity measurements over a temperature range of 20-200 K and a wavelength range of 6-800 μm.

“A refrigerator was employed as the cold source and incorporated a diamond window, enabling emissivity measurements over a temperature range of 20-200 K and a wavelength range of 6-800 µm.”

Radiation signals in the Herve et al. system were detected using a bolometer, and emissivity values were calculated with reference to a calibrated blackbody.

“Radiation signals were detected using a bolometer, and emissivity values were calculated with reference to a calibrated blackbody.”

Herve et al. (2008) developed a low-temperature emissivity measurement system based on the radiometric method.

“In 2008, Herve et al. [37] from Paris Diderot University developed a low-temperature emissivity measurement system based on the radiometric method as presented in Figure 8.”

The evolution of radiometric methods reveals a trend in cooling methods from reliance on external cryogenic liquids (such as liquid nitrogen and liquid helium) to integrated refrigeration systems.

“Initially, cooling methods evolved from reliance on external cryogenic liquids [17,44,49,55], such as liquid nitrogen and liquid helium, to integrated refrigeration system [37,54].”

There has been a transition in the arrangement of key optical paths from external detectors to fully integrated designs.

“Secondly, there has been a transition in the arrangement of key optical paths from external detectors [17,37,49,55] to fully integrated designs [54].”