wavLength interview: Harnessing the power of cell phones to detect threats of nuclear terrorism

Researchers at Purdue University are developing a system to use cell phones to help detect radiation from dirty bombs and nuclear weapons. They've successfully tested technology that places sensors and special software inside consumer cell phones to detect and track sources of suspicious radiation. They're pushing to blanket the country with radiation sensors by placing the technology in cell phones as well as other devices like laptop computers.

Purdue physics professor Ephraim Fischbach says the ubiquitous nature of cell phones gives the system power.

FISCHBACH: An individual who is in, let's say, midtown Manhattan, would find it very difficult to avoid the many thousands of people with whom he would come in contact, all of whom could be detecting his radiation and transmitting this information to a central law enforcement location.

wavLength: What is the technology leap here?

FISCHBACH: All the ingredients - that is, radiation detectors and cell phones - these already exist. The real leap is in combining these with software that puts all of this together, and the algorithms that tell us how to combine all of this information and which can by virtue of these algorithms specifically and quickly locate where the source of radiation is. What's critical in this is to eliminate obvious background sources of radiation which exist everywhere, near hospitals and Grand Central Station in New York where there is a large radioactive background. All of this would be available to the central location where all this is sent to, so that's the leap.

The radiation-sensing technology is designed to avoid false-positive detection, according to its creator, consulting instrumentation scientist Andrew Longman.

LONGMAN: The more data you have to work with, the better you can calculate what's real and what isn't.

wavLength: I imagine that this would be designed in a way in which individual users would not know their cell phone had just detected radiation.

LONGMAN: Yes, and and actually individual cell phones by themselves don't actually do the detection. It's all the cell phones working together. And so to determine that there was actually some nefarious material in a certain place, there would be information drawn from whole bunches of them, and in so doing you make the whole process much more sensitive and much more accurate. You're correct that the individual would not have any interaction with the system, but just the motion of the individuals as they walk around in their daily lives would be the great benefit that we would be getting.

wavLength: What are the biggest roadblocks to getting this system to happen?

LONGMAN: Cellular companies don't like to have anything additional packed into a phone because they work very hard to make phones ever smaller and lighter, but we really believe that if the public realizes and grasps the opportunity here the public will respond to both corporations and the government and say, "Hey, look, we really want this."
(q/a)

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