Hot electronics for response
Sensors based on silicon carbide can withstand temperatures five times as hot as existing electronics
By Doug Page
Radio transmitters able to operate in temperatures up to 900 C (1,652 F) may soon be available to give first responders a safer way to monitor the effects of a dirty bomb.
The state-of-the-art technology, being developed by researchers at Newcastle University in the United Kingdom, uses silicon carbide electronics. The main feature of SiC is its ability to withstand temperatures in hostile environments equal to those inside a running jet engine or a burbling volcano, or the extreme radiation that might be found in a subway tunnel after a dirty-bomb detonation.
Conventional silicon-based electronics have an operational limit of 175 C (347 F). Unless hardened by expensive special processes, conventional electronics are also vulnerable to ionizing radiation, making them unreliable in radioactive environments; a single charged particle can knock thousands of electrons loose, causing electronic noise and signal spikes.
"Silicon carbide electronics will allow electronic monitors to be placed in locations which are just not possible with conventional silicon-based electronics," said Alton Horsfall, an electrical, electronic and computer engineer at Newcastle University.
The heat-tolerant characteristics of SiC are the result of its unique molecular structure, which makes it more stable than silicon. SiC is also chemically inert and has a high radiation tolerance.
Horsfall said this means that preventive maintenance systems can now be created that can be deployed in places previously off-limits to conventional monitors, such as nuclear reactors, jet engines or oil wells.
"This opens up the possibility of monitoring and therefore controlling a wide variety of systems, with a view to improving efficiency," he said.
The new electronic technology also opens up opportunities for homeland security applications that demand a resilient monitoring system, one that will operate in almost any environment, no matter how hot or radioactive. One such application is to monitor air quality after a dirty-bomb incident for radioactive particles in an enclosed area, such as underground transit system.
Horsfall told Homeland1 that if a dirty bomb were detonated in, say, the metro Washington, D.C., subway system, previously deployed SiC-based monitors could safely measure the amount of radiation and transmit contamination levels to first responders, information that is currently obtainable only by entering the area of contamination.
The Horsfall team has developed the necessary electronic components and is now working to integrate them into an unobtrusive, inexpensive device about the size of an iPhone that can be placed ubiquitously in areas of concern.
Moreover, Horsfall believes the technology is so robust it could even work in the bowels of an active volcano.
"At the moment we have no way of accurately monitoring the situation inside a volcano, and in fact most data collection actually goes on post-eruption," he said.
With an estimated 500 million people living in the shadows of volcanoes around this world, this clearly is not ideal.