DIGIRAD’S NEXT-GENERATION EARTH AND SPACE SCIENCE MISSIONS

An X-Ray Spectrometer using state-of-the-art detector technology will be launched this year on the Clark spacecraft, one of two missions to be flown as part of the Small Spacecraft Technology Initiative. Under SSTI, NASA funded the development of “Clark,” a high technology demonstration satellite to provide 3-m resolution panchromatic and 15-m resolution multispectral images, as well as collect atmospheric constituent and cosmic x-ray data. The 690-Ib. satellite, to be launched in early 1997, will be in a 476 km, circular, sun-synchronous polar orbit.

The primary objective of this mission is to demonstrate new technologies for small spacecraft. In keeping with this philosophy, we use two new types of semiconductor X-ray detectors, both operating near room temperature: avalanche photodiodes and cadmiumzinc-telluride detectors. The main purpose of flying these detectors is to test them in a space environment so that they can be used with confidence on future space missions. Measurements of solar flare and gamma-ray burst X-ray emissions will also be made as well as atmospheric constituent and cosmic x-ray data.  Digirad will measure these emissions.

To assist, Digirad developed a new class of solid-state detector arrays with microelectronics readout circuitry for two-dimensional imaging of x-ray and gamma ray fields in support of next-generation Earth and space science mission requirements.   The approach uses cadmium zinc telluride (CZT), a new room temperature detector material first developed by Digirad. Recent results show that CZT detector arrays can exhibit high detection efficiencies and superior energy resolution from below 1 kev to above 600 kev. CZT detectors are robust and lightweight; and can be patterned in a variety of array structures, with pixel dimensions to well below 100 m.

The innovation of producing CZT imagers suitable for space meets the needs of NASA small missions initiatives. 

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For more information in Canada on Digirad's solid-state technology for advanced Nuclear Imaging, please contact your local ADN Canada sales consultant Toll-Free in Canada at 1-877-434-5311 or via e-mail.  Note: Any / all product names mentioned in this document may be trademarks or registered trademarks of their respective companies and are hereby acknowledged.