Using Radio Waves to Detect Explosives

deadmantyping writes "A Japanese research group published a paper describing a method to detect explosives in luggage using radio waves. The method relies upon nitrogen nuclear quadrapole resonance (NQR) and is able to distinguish between different white powders, whereas currently used x-ray technology is not."

Interesting idea, but one caveat I perceve...

[MBC1977]

Hmmm.... seems plausable, since if my memory serves me correctly, all matter gives off a distinct waveform. Just one question (or problem?), what happens if the crazy terrorist (er.. freedom fighter) decides to make a trigger which works off of radio waves (or whatever particular radio wave) said name future machine may use?

Re:So, no more taking shoes off?

[QuantumG]

Please take off your: jacket, shoes, backpack (and take the laptop out of the backpack and put it in a seperate tray), hat, belt, mobile phone, keys, wallet (if it contains more than 3 rfid based entry keycards). Yes, I travelled international recently. It's not even consistent.. some places they'll make you take off your belt, other places, no, that's fine.

Time before last I took a suit coat with me. Big solid metal coat hanger with nice sharp edges. They just let me carry it onto the plane. Had I tried to take a similar piece of metal on (say, a boxcutter) they would have denied me. Hmmm, wonder if there's a little big of class disparity there.

The illusion of safety.

Re:It's not a cure-all

[budgenator]

Nothing (plausible) can detect everything that might be explosive, Actually even what an explosive is can be kind of ambiguous; still I've read that terrorists are more likely to use peroxide based explosives rather than nitrate based explosives. I see the nitrogen nuclear quadrupole resonance as have more potential in finding IED in the road beds in places like Iraq.

Re:It's not a cure-all

[Entrope]

NQR detectors tend to be relatively slow to examine an area, and a very important factor in Iraq is a fast rate of advance. NQR might work for airports, but other systems -- like metal detectors and backscatter radars -- work better when you need to go fast. The military mostly looks at NQR as a confirmation technology for other detectors and not as the first line of explosive threat detection. (Google "NQR rate of advance" for various papers and studies on the issue.)