Lobbing Sensors Into VolcanoesSeptember 24, 2010 By: Melanie Martella, Sensors
Over the years, there's been interest (and a bunch of money and hard work) devoted to creating electronics (and sensors) that can boldy go where more traditional sensors and electronics cannot go without melting into a puddle. Or, at the very least, ceasing to function as desired. Recently, researchers from Newcastle University's Center for Extreme Environment Technology developed sensors based on silicon carbide that can operate in temperatures to 600°C with the aim of placing them into volcanoes to detect changes in the mixture of gases emitted by our lava-producing friends and thus providing an early warning of eruptions.
Note that I said into volcanoes. Silicon carbide (SiC) is far tougher than silicon—it resists radiation damage to a greater extent and its much stronger bonds mean that it can operate up to a theoretical maximum temperature >900°C. While its electron and hole mobilities are less than those of silicon, it's got a higher thermal conductivity and a higher critical breakdown electrical field. Actually, if you're interested at all in learning more, the team maintains the Resilient Technology blog, which also contains links to the various presentations and projects underway. Fascinating reading. Note also that they aren't the only ones working with (and on) silicon carbide. NASA Glenn Sensors and Electronics Branch, for instance, created and built a differential amplifier IC chip that operated at 500°C, continuously, for 2000 hr. Entities that deal with extreme environments, such as the military and aerospace companies, are very interested in creating high-temperature semiconductor devices.
Has the press release on Dr. Alton Horsfall's and Dr. Nick Wright's work garnered all kinds of interest, including queries from non-volcanologists who need devices capable of operating in extreme environments? That would be a big old yes. Will everybody start using silicon carbide? Not yet; although the price tag is coming down, it's still got a ways to go before silicon carbide is as cheap as silicon.
The other important point I'd like to make (other than holy cow this stuff is cool) is that where you take the measurements matters. If you want to know what's going on in a volcano, in addition to all the things you can learn from its exterior, ideally you want to supplement those with measurements taken from its interior. If you're studying a hurricane or a tornado, you want to be able to take measurements from inside the storm or the funnel cloud. You can't adequately model something without sufficient data, and sensors that can operate in extreme environments can help you to attain that data.
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