Environmental Evaluation Of The Ulis Pico1024 Microbolometer

In recent years the European Space Agency (ESA) has been pursuing studies dedicated to Earth imaging from space in the Long Wave Infrared region for applications ranging from monitoring of evapotranspiration, and water resources management to the development of urban heat island and monitoring of high temperature events. Among the various solutions being studied is also that of a low cost instrument with moderate needs in terms of resources.One potential enabler for such type of mission could be the technology of microbolometer detectors. The latest generation of microbolometer arrays now available offer large formats (XGA) and small pixel sizes which are favourable for keeping the instrument size within reasonable limit while addressing larger swath compared to VGA format. A major concern however, in using commercial microbolometers in space is their ability to sustain the radiation environment of space but also the harsh mechanical environments. COTS microbolometers are potentially susceptible to SEE (single even effects) because of the use of commercial CMOS technology/libraries and no implementation of specific design rules (i.e. space tailored rad hardened). In the past, and in the context of their national program, CNES has performed a space evaluation of COTS microbolometer arrays of 640x480 with 25 mu m pitch[ 3]. Despite successful gamma irradiations and vibration tests; degradation of the ROIC has been evidenced during the heavy ions tests, which makes the full qualification of COTS microbolometers for future space programmes mandatory. Similar tests have been performed on an even earlier device (384x288 with a pitch of 35 mu m) under the ESA EarthCARE programme[ 2].ESA and Thales Alenia Space have recently run an activity with the objective to validate a third-generation COTS microbolometer offered by ULIS (France) against the relevant environment for a candidate Thermal InfraRed (TIR) space mission. The micro-bolometer selected is the PICO 1024E[ 1], which offers 1024x768 pixels of size 17 mu m square. The validation sequence included the main types of irradiation tests required by a space application as well as vibration and shock tests. Ageing tests are included and synergetic effects are also investigated. The detector performances were tested before, after and during any test sequence. In this paper, the results of this activity achieved in the beginning of 2017 are reported.