In the frame of technological preparation for scientific Earth observation, the European Space Agency (ESA) has undertaken a study program for an infrared instrument intended to be implemented on a polar platform type satellite: HRTIR (high resolution thermal infrared radiometer) will be a support for the study of land surface processes by providing reliable information on both temperature and emissivity. The HRTIR instrument, designed under Matra Marconi Space (MMS) leadership, will observe the Earth in three IR spectral bands ranging from 8 micrometer to 12.5 micrometer with a spatial resolution of 50 m and a swath width of 50 km. One of the major challenges is to develop and implement 1000 elements linear arrays at such long wavelengths. SOFRADIR, with LIR support for technology, is responsible for the detectors development. A detector breadboard has been studied and developed to be operated in the most critical band, i.e. 11.5 - 12.5 micrometer. The breadboard is made of three HgCdTe modules mechanically butted and hybridized to two CCD multiplexers. To achieve the required 0.1 K NEdT, the detector is operated at 50 K; the mechanical butting is designed with the objective of zero dead pixel at the butting joints. The detector breadboard has been integrated in a focal plane and detection chain breadboard at MMS to be fully characterized. The results have proven the very high quality of LIR/SOFRADIR HgCdTe material beyond 12.5 micrometer together with a high photodiode production yield. The feasibility of mechanical butting was also demonstrated although further investigations and tests still have to be carried out to significantly increase the butting yield.

Date Published: 8 September 1995
PDF: 12 pages
Proc. SPIE 2552, Infrared Technology XXI, (8 September 1995); doi: 10.1117/12.218286

Published in SPIE Proceedings Vol. 2552:
Infrared Technology XXI
Bjorn F. Andresen; Marija Strojnik, Editor(s)