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New Explosive Detection Tech
cruci writes to tell us Yahoo! is reporting that a New Zealand company, Syft, has developed a new way to detect many different kinds of explosives (and their individual ingredients) in real time. Designed for what the company calls "photocopier simplicity", CEO Geoff Peck claims that the technology is ready to deploy immediately and is already deployed in some ports and hospitals. From the article: "The Voice100(TM) employs Selected Ion Flow Tube - Mass Spectrometry (SIFT-MS). While SIFT-MS has been in academic use for more than 20 years, Syft Technologies is the first company to offer a commercial instrument with the full discriminating analytical power of a laboratory-grade mass spectrometer."
"The Voice100(TM) employs Selected Ion Flow Tube..."
It's a bunch of tubes I tell you!
If you have these exquisitly sensitive machines that can detect even a few molecules of material, aren't they by the same token super-vulnerable to being attacked by "chaffing" or overloading?
You have to look at the false positive and negative rates for detection. If you have a test that is 99.99% specific, it will still fail in practical use in an airport, as that means that 1 out of 10,000 people will come up positive. If you have a lot of people going through you will still have a big problem (London had over a million flights last year). This is the same issue as using automatic detection of terrorists – It's one thing to match/no match a known ID (e.g. biometric passport) to a person; it's another to match every passer by to every known terrorist.
Going back to chemical detection: this level of sensitivity will mean that every person runs the risk of coming up positive eventually. This amounts probably about 100,000 people in the U.S., and lots more elsewhere in the world.
IANAC (I am not a chemist) but this guy seems to make a pretty solid arguement: http://www.interesting-people.org/archives/interes ting-people/200608/msg00087.html
Not the U.S. I think we made it adequately clear that our DHS doesn't exist to improve homeland security, rather just to scare the citizenry.
Someone had to do it.
Try to light all suspicious materials on fire. Nice and cheap (all you need is some guy you pay minimum wage with a handheld lighter). For larger items, have a can of hairspray handy to use as a cheap flamethrower.
I Am My Own Worst Enemy
We should be detecting bombers not bombs. Bombs form a nearly endless variety. Bombers are an easier class of object to detect, I believe. The fact that the bombers try to hide the bombs on their person or in their carry on luggage suggests they they themselves don't fear the system's scruitiny. In the old days they had to figure out ways of getting the bomb on the aircraft without them being anywhere near it. How times have changed.
I work in a chemistry lab where we regularly synthesis small quantities of explosives. Last weekend I took a flight and (very stupidly) wore the same shoes that I normally wear to work. They swabbed my shoes down and passed me through without a second glance. It didn't occur to me until after I was through security that there was surely some trace amount of explosives on my shoes that should have been detectable. Upon further reflection I realized that the detector was probably only set to look for a few certain common explosives, and the explosive compounds that we work with in my lab are relatively esoteric.
I think that the very narrow specificity of these machines is a major problem. You might be able to detect the 20 most common explosives, but it would be trivially easy for any competent organic chemist to come up with a new explosive that the detector wouldn't be looking for. Perhaps the detectors that we have now look for nitroglycerin, but what about nitroglycerin with an extra methyl group hung off the end of the carbon chain? Or an ethyl group? Or an isopropyl group? What if instead of ammonium nitrate you used butyl-ammonium nitrate? Or butyl ammonium with some other, less common oxidizer like permanganate/perchlorate/whatever? Do you see my point? You could make a slight modification to almost any existing explosive and render it undetectable to these bomb scanners, because the scanners only look for things that they have been specifically trained to look for. They have no capability to actually examine the structure of a molecule and judge whether it's explosive or not. It's kind of like using a "knife detector" that has been set to look for the most common brands of knifes, when in fact you could sharpen almost anything into a knife with a little effort.