Broadband Radiometer Detectors

The Broadband Radiometer (BBR) is an instrument being developed for the ESA EarthCARE satellite. The EarthCARE mission objective is aimed at providing a better understanding of the Earth’s clouds, aerosols and radiation interactions. Four instruments are needed on the EarthCARE satellite and one of them is the BBR instrument, for which the detectors development are under our responsibility.

The BBR detectors use the VOx-based uncooled microbolometer detector technology. We developed a custom linear 30-pixel microbolometer focal plane array (FPA) on 100-µm pixel pitch. The linear array is hybridized with an external readout circuit in an assembly that further includes a circuit card assembly providing signal routing, passive components, and an interface connector to the instrument electronics. The assembly is completed by a mechanical base plate and cover for alignment with the instrument telescope.

To ensure a broadband flat response, the linear array is coated with gold-black. Our approach included manufacturing of prototypes early in the development to confirm the suitability of our technologies for the application. A gold-black deposition facility has been developed and built to meet the needs, not only of the BBR instrument, but of future broadband applications as well. The gold-black facility was commissioned and the process parameters were subsequently optimized to achieve deposits meeting the requirements of the BBR detectors. Given the gold-black facility’s capabilities in terms of control and monitoring, the process and resulting deposits can be adapted to other specific needs. Pixel definition of the coated FPA is ensured by ablating the gold-black material by a high-resolution micromachining system, which was designed, developed and implemented in our cleanroom laboratory. Our capabilities for laser micromachining cover a wide range of applications.