Carbon-nanotube Field Emission X-ray Tube for Space Exploration Xrd/xrf Instrument
نویسندگان
چکیده
The deployment of in-situ miniature XRD instruments for planetary exploration requires small focus bright X-ray sources that are physically small, lightweight, robust, and power efficient. Existing miniature X-ray tubes are limited by inefficient thermionic electron sources. We have investigated the potential of carbon nanotube (CNT) field emitters for improving the efficiency and durability of miniature X-ray tubes. CNT field emitters were fabricated using a thermal CVD growth process. High, sustainable current densities of over 1A/cm were routinely measured from these emitters. CNT cathodes implemented in miniature X-ray tubes have shown improved efficiency and robustness. Focusing optics are being designed to yield the small focus required for XRD. The resulting miniature microfocused X-ray tube will be part of the CheMin XRD/XRF instrument, proposed for the Mars 2009 Mars Science Laboratory mission.
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