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Technology Science

Explosives Detection Breakthrough Via Green Laser 49

Posted by timothy
from the stuff-that-blows-up dept.
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."
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Explosives Detection Breakthrough Via Green Laser

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  • This is way cool. All though now everyone knows how it works...
    • Re:Cool! (Score:2, Insightful)

      by Anonymous Coward
      It is GOOD that the information is public. Who cares about patenting something like this? We are talking about saving lives. Anyone who tries to patent something SO USEFUL to every country in the world is a greedy bastard.
      • by Psion (2244)
        If it's so useful, then why doesn't it make sense to reimburse and reward the person who discovered it?
      • So now we will have research into explosives that not only have no smell, but no photoluminescence(sp?) as well? Now that we know it is possible to detect them like this it only makes sense...
  • by G4from128k (686170) on Wednesday October 20, 2004 @08:01AM (#10574066)
    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.
    • by ConceptJunkie (24823) on Wednesday October 20, 2004 @08:36AM (#10574230) Homepage Journal
      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.
      • those big, nasty bomb-sniffing dogs

        The only bomb-sniffing dogs I know are real pussycats. They have the kind of disposition that you trust with the baby, even when the baby is teething and thinks chewing on the dog's ears will help.

        • Yeah, but that didn't make for a funny joke. It seems to me that bomb-sniffing dogs would have to be docile because you are not using them for their aggression, but for their ability to sense and communicate.

          • True enough. A lot of people think of dogs like that as really ill-tempered, aggressive animals, though, and I hate to see the stereotype reinforced.

            Far as I can tell, bomb-sniffing dogs are chosen for intelligence and mild disposition. The former so they can learn what they need to know, the latter because they do their work around strangers a lot, and it doesn't do to have the dog wig out over the number of strange people in the area while it does what it was trained to do.

      • Just wondering. What is it about (food grade)meat that prevents humans from being a potential false-positive.
        • Skin holds in the molecules in question?

        • AFAIK, nitrates/nitrites don't occur naturally in mammilian organisms. (Someone please correct me if I'm wrong.) They are added for their preservative qualities during processing, which is why certain meats (esp. bacon, hot dogs, some sausages, etc.) will cause false positives, while others (steaks, chicken, etc.) will not.

          Incidentally, it's a good idea to stay away from nitrate/nitrite-laced meats anyway; they're really not good for you. Having a diet coke and a hot dog? The aspartame in the diet coke
    • by erykjj (213892)
      I don't remember much from my chemistry class, but apparently they tested it with "benzene, naphthalene, nail polish, perfume, lighter fluid, rubber cement, acetone, toluene, fertilizer on golf shoes, sugar, baking soda, polyvinyl pyrrolidone (PVP), paint thinner and more" and nono of these triggered the alarm. I'm sure some of these contain the nitrites you mentioned, no?
      • > I'm sure some of these contain the nitrites you
        > mentioned, no?

        There is some nitrit included in your list. But please remember, that the absorption and emission wave length not only depend on a single atom or bond but are also greatly influensed by the surrounding bonds/structures.

        Your list is nothing but a first indication if the choosen method should be investigated.

      • by Kobal (597997)
        Most of those compounds don't even contain nitrogen, let alone nitrites. The closest call would be fertilizer, where there can be nitrites along nitrates.
        On the other hand, while nitrites are still allowed as preservatives and colour fixatives in meat products, they should have been banned long ago. Such accidents [nih.gov] are unfortunately still pretty common. 1g is usually considered as a fatal dose.
  • by redelm (54142) on Wednesday October 20, 2004 @08:48AM (#10574313) Homepage
    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.

  • upping the ante... (Score:3, Interesting)

    by da5idnetlimit.com (410908) on Wednesday October 20, 2004 @09:16AM (#10574501) Journal
    ok, that means that to build a bomb you need laboratory equipment with gas control (think big glass box) and a tight seal allowing you access to the INSIDE of the bomb container.

    you then have to find a way to seal the container air-tight (low-tech :generous grease application for example) then flush air, introduce clean container cap, close container...

    ok.. we just upped the ante and non-professionnal bomb makers won't be able to make the technological jump...=>more security

    but it's nothing that someone with some organisation couldn't do...but we have to assume anyone with that sort of hardware is checked and easier to find out.

    Alas, after going through this procedure (or any other they think of) they (terrorists-bomber-mad(wo)men now only have to get said night visions googles and green laser and test it themselves...

    just another check in in the seemingly already complicated art of making bombs (I wouldn't know, as IANAB -I Am Not A Bomber - 8p )

    I think they should have kept it a secret longer, even if they precised it was already one year old...
    • by Carnildo (712617)
      There's no indication that old-fashoned blackpowder will trigger the detector, and if fertilizer won't trigger it, then a fertilizer/fuel oil mix probably won't either.
  • So the physical fact that green lasers and NVGs can be used to detect explosives, of resideue, (or soap), is now a patentable process.

    Never mind all that stuff about physical phenomena being unpatentable. Here at the USPTO we grant with prejudice to trifling things like gross obviousness, unoriginality and indeed patentablity itself.

    Applicants for patents on Earth, Air, Fire and Water are now currently being considered.

    P.S.
    If anyone, including all you foreigners, doesn't like it, be prepared for our lawyers to WIPO you into povert^H^H^H^H^H^Hsubmission.
    • Umm, Sorry, but those four terms have already been taken as separates and as a single term by a great band from the 80's. (ole!)
    • So the physical fact that green lasers and NVGs can be used to detect explosives, of resideue, (or soap), is now a patentable process.


      No, that isn't what was patented. The critical bit that was patented was the discrimination that eliminates false positives. So buy, use, and sell all the green lasers and night vision goggles that you want. Just don't try to sell a combined laser/NVG device that has the ability to turn on the correct filters.
    • by francisew (611090)

      They're patenting the creation of such a device (characteristic filters and design) for use as an explosives detector. This is reasonable. As much as patenting a light bulb or a new kind of car engine. A light bulb is just a fancy resistor in a clear vacuum case, right? New LED's are just chemicals stuck between electrode's, right?

      This is pretty basic chemistry, and it is quite interesting. My lab does similar stuff in the biomedical/chemical sensing area. We avoid work that involve weapons and things tha

  • by VernonNemitz (581327) on Wednesday October 20, 2004 @09:47AM (#10574742) Journal
    They've been looking for a good remote land mine sensor. Maybe this is it!
  • "This invention is almost a year old now, because at first people here did not believe us -- that no one had thought of this before. But when they checked the literature and found we were right, they told us we couldn't tell anybody until they got a patent on it," said Hummel.

    I wonder how many lives could have been saved already if they hadn't kept this under wraps for a year...
  • by Zachary Kessin (1372) <zkessin@gmail.com> on Wednesday October 20, 2004 @11:17AM (#10575567) Homepage Journal
    Can it see if a bag contains a bomb or some one's school books from outside? That would be useful. I have lost count of how many times I have been held up because someone left a bag somewhere and they had to call in the bomb squad to see if it is a bomb or someone's laundry/groceries/school books etc. This is not a place where you want false negatives!
  • Easy to Fool? (Score:3, Insightful)

    by LightForce3 (450105) <lightforce3&yahoo,com> on Wednesday October 20, 2004 @11:39AM (#10575800) Homepage
    Correct me if I'm wrong, but wouldn't the detection scheme described in the article (two infrared sensors, one with a 705-nm filter, and the other without a filter to eliminate false positives) be easy to fool by masking the explosive with another substance that also photoluminesces at 705-nm?

    For example, suppose non-explosive substance foo photoluminesces at and around 705-nm, and is normally allowed past the detector because it lacks the special signature. If you were to put a bunch of foo in the same container as your explosive, thereby combining the infrared signatures (if that's actually what would happen), couldn't you fool the detector?

    Of course, the article is light on real details, and I'm no chemistry expert, so maybe it's not that easy to fool.
    • wouldn't the detection scheme described in the article... be easy to fool by masking the explosive with another substance that also photoluminesces at 705-nm?

      Very good point. Throwing more CPU at the problem, and analyzing the spectra in greater detail might be able to get around that. (For example, perhaps the peak at 705nm would be higher than the other wavelengths near it.)

    • True. But wouldn't the thing that was luminescing get extra attention? Wouldn't that be a good thing?

      And since explosives are so reactive, there is outgassing which produces a small chemical trail (how dogs can sniff explosives), which means that you can't hide the smell of the bomb by sealing it up.
  • They already have the night-vision goggles. Might only work for detection at night, but that's better than the current status quo...
  • others figure out how to mask it or simply keep it in.
  • by patniemeyer (444913) <pat@pat.net> on Wednesday October 20, 2004 @05:27PM (#10580067) Homepage
    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
  • by Muhammar (659468) on Wednesday October 20, 2004 @06:54PM (#10580914)
    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.
  • With his lab's high-resolution photoluminescent meter, one of his students performed a simple test that no major lab had thought to perform before It angers me that they didn't even bother to name the student who thought of it. Meanwhile the emeritus professor gets to bask in all the glory of keeping the homeland safe. This has a long history, and misappropriation has been ingrained into the academic culture. Offhand I can think readily of a couple of similar examples, such as the discovery of pulsars w
  • After actually RTFA, I'm impressed. This could make homicide bombers highly visible, 1/2 mile before they get to their target. I suppose it may also be possible to extend the technology's sensitivity to allow airborne spotting of weapons stashes and bomb-making facilities. Anyone holding a significant amount of C4 is going to be visible from a distance, and the larger the amount, the larger the distance. (Will an ammo dump be visible from orbit?)

    If so, this technology could make a lot of terrorist meth
  • My bomb explodes when exposed to 325 - 532 nm green laser wavelengths!

Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true. -- Bertrand Russell

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