Uncooled microbolometer detectors are well suited for space applications due to their strong performance and their low power consumption, low cost and low mass. Furthermore, being thermal detectors, the spectral range of their response spans from the mid- to the far-infrared, thus meeting different mission requirements. In order to take the absolute temperature measurements necessary for many infrared Earth Observation applications, variations in thermal background due to fluctuations of the ambient temperature should be minimized. This can be accomplished by integrating the microbolometer focal plane array (FPA) into a package offering a very stable thermal environment. The use of a radiometric package in these applications reduces the frequency of offset calibrations while limiting the need for system temperature control, thanks to the stabilization of the detector thermal environment provided by the radiometric package.
The radiometric packaging technology developed at INO is designed to be modular and adaptable to different microbolometer FPA packages meeting a variety of application requirements. To that aim, most of the components used in the package are either commercial off-the-shelf (COTS) or manufactured at INO, and can be easily adapted to the packaging of different FPAs in order to meet various optical and performance-related requirements (e.g., numerical aperture, temperature stability, stray light rejection, operating spectral band) without altering the packaging procedure.
This approach enables INO to offer its space qualified radiometric packaging technology for different space instrumentation applications
A Noise-Equivalent Temperature Difference (NETD) as low as 23 mK was measured with INO’s IRL512 FPA in a radiometric package:
Broadband filter centers in the 8-12 µm wavelength band
140 ms integration time
Characterization in flood exposure
The radiometric package successfully passed the following environmental tests:
Thermally cycled from -55 to +85°C according to MIL-STD-810
Randomly accelerated up to 14G RMS from 20-2000 Hz
Shock tested up to 75 G
The package also shows a very low sensitivity to stray radiation due to a specially designed, high-efficiency radiation shield.
Under the Space Technology Development Program of the Canadian Space Agency (CSA), INO has designed, assembled and radiometrically characterized a radiometric package for its 512x3 pixel microbolometer FPA. The design of the radiometric package was based on INO’s FPA, allowing the development of a small, low weight, low power consumption sensitive detector package ideally suited for infrared pushbroom imaging applications.