Infrared sensor array for high precision at relatively low temperature ranges

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fully assembled unit

Technology abstract

The offer relates to an infrared sensor array for accurate hyperspectral thermal imaging in relatively low temperature ranges used in Earth observation. The sensor array is used on the Sentinel 3 spacecraft to measure the ocean temperatures and to detect fires. Its typical advantages are accuracy and high resolution in a relatively low temperature range down to zero C.

Technology Description

For the SLSTR instrument (Sea and Land Surface Temperature Radiometer) of the Sentinel 3 satellite, infrared detector arrays were developed for six different IR spectral channels. The earth’s surface is scanned in all these bands to determine the total sea temperature and temperature distribution over the oceans. As one of few detector producers, the originator of this technology is in a position to offer the required highly sensitive MCT-IR detector arrays from one source, building an integrated hyper-spectral sensor array with high resolution and sensitivity in a relatively low temperature range. To support this, a small cryogenic unit is attached to the sensor to provide cooling. Most existing IT sensors are aiming at higher temperature ranges, such as detecting people, hotspots in equipment, or even jet engine exhausts.

Innovations & Advantages

Infrared sensors are characterized by the sensor material used, the infrared spectral band of maximum sensitivity, the overall sensitivity, and, in case of sensor arrays, the possibilities of the control software and other interface technology. The sensor array for Sentinel 3 is specifically sensitive in a range of infra-red wavelengths between 0.95 and 2.45 mu, to measure the Earth’s ocean temperatures that typically vary between 0 and 25 C. The sensor array consists of 1024 x 256 individual sensors, offering a digital image via a standard Color Television Interface Adapter (CTIA). Its specific properties are a combination of high accuracy, high resolution, and relatively low temperature range.

Further Information

The IR detector material is MCT and has a quantum efficiency above 60%, and a fill factor above 65%. The pixel area is 20 mu x 28 mu, the unit has 8 CMOS ROIC outputs, and programmable integration times between 1 and 4 milliseconds.

Current and Potential Domains of Application

The unit has been designed specifically for measureing the temperatures of the oceans, but many non-space applications may also be interested in accurate thermal imaging in this range. Suggested applications may be medical, food industry, drinking water purification plants and similar applications, monitoring of ship spillage in harbours, etc.