Explosives Detection Breakthrough Via Green Laser

retiarius writes "In keeping with celebrating the USA's National Chemistry Week (aside from watching the hitcount for Tom Lehrer's very chemical music video at CD Baby), I'm duly impressed by an amazingly simple new way to detect explosives at a distance -- just use a store-bought presentation green laser pointer and some dimestore infrared night vision glasses! The (alas, patentable) details are in this week's EE Times."

Comments

False positives & meat

[G4from128k]

A quick read of this article suggests that this will have a false positive problem with meat products. The nitrite (NO2) groups found in explosives that glow IR when exposed to green light are also found in meat products. I'm surprised the researchers did not test this potential source of false postives because other explosives detection technologies that look for nitrogen are also fooled by meat products.

Eat a hot dog or deli sandwich before going through security and you may end up in the dreaded secondary screening line when the bomb detector mistakes bologna for a bomb.

Re:False positives & meat

[ConceptJunkie]

What's worse is if they pull you out of the line because of a false positive, and then bring out those big, nasty bomb-sniffing dogs and YOU smell like MEAT.

Yikes!

Now I can't take bacon on planes. Oh well, it's for security.

Why alas? US govt can use patents royalty-free.

[redelm]

Explosives detection technology is most likely to be used by elements of the US government, specifically the DHS, TSA and other TLAs. Patents make no difference to the US government -- it has a perpetual, royalty free licence to use any patent it wishes, any way it wishes. Frequently disasterously.

Once debugged (meat), the mfr will probably be able to sell the devices to the govt. If they charge too much, the GSA (procurement) will go out for bids. Local and state bomb squads will have more trouble, but the Federal govt could just give them detectors under some fancy pgm.

Doesn't chaff defeat any detection device?

[patniemeyer]

I've always wondered about this... Whether it's dogs sniffing drugs or million dollar machines sniffing for explosives - Why don't the bad guys just contaminate the entire area so that you can't use the detector? I mean, wouldn't somebody walking around spilling some nitrate material all over the airport carpets just ruin that airport permanently?

If it's so sensitive that the bad guys can't cleanse themselves of it, how could one possibly clean an entire airport?

Pat

Useful only as first-screen method

[Muhammar]

1) This is simple, non-contact method but it relies on a spectral signature general for nitramines and nitro-aromatics. Some chemicals used in parfumery (artificial musk scent) have nitro groups - so there will be false positives.

2) This method will not work for acetonperoxide (the super-unstable explosive prefered by Palestinian suicide bombers and the wannabe shoe-bomber Reid - because acetonperoxide does not contain any nitros) and for fertilizer bombs (no volatile nitroorganics there).

3)Also, this detection method can be fooled by masking the narrow fluorescence signature of nitro explosives by adding other chemicals with broad fluorescence to confuse the instrument into thinking "this is a false positive". All it takes for the bad guys to get hold of the detection device and experiment with some common household, drugstore or paintshop materials to find the right stuff to spray onto their luggage making it immune for this detection. It may well be that a laundry softener or moskyto repellent can threw this techique off.

4) The currently used swab-tests/mass spectrometry analysis at the airports recognize very characteristic ion mass (of the parent molecule and its fragments) - the signal pattern unique for each explosive, so this masspec method is harder to fool and less likely to give false positives.