Fast, Accurate Detection of Explosives

It doesn't come easy writes "Fast, highly reliable detection of residues that could indicate the presence of explosives and other hazardous materials inside luggage is now possible with technology under development at Purdue University. Recent improvements to a previously developed prototype have proven successful at detecting at the picogram (trillionths of a gram) level in lab tests, about 1,000 times less material than previously required. From the article: 'In the amount of time it requires to take a breath, this technology can sniff the surface of a piece of luggage and determine whether a hazardous substance is likely to be inside, based on residual chemicals brushed from the hand of someone loading the suitcase.'"

Comments

Vulnerable to a "chaffing" attack?

[patniemeyer]

Ok, here's something I've always wondered about. 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?

Couldn't a bad guy simple walk around the airport with some material on his shoes and permanently, for all time, destroy the effectiveness of the instruments? I mean, how could one possibly clean a whole airport down to a few molecules worth of the stuff?

Isn't that a *huge* hole in any "super sensitive" chemical detection system?

Re:Vulnerable to a "chaffing" attack?

[mgv]

Ok, here's something I've always wondered about. 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?

Its worse than that. You have to look at the false positive and negative rates for detection. If you have a test that is 99.9% specific, it will still fail in practical use in an airport, as that means that 1/1000 people will come up positive. (I think I have the right statistical measure here, but apologies if not). If you have alot of people going through you will still have a big problem -London had 1 000 000 FLIGHTS last year, so the equivalent of 1000 plane loads of people will come up positive per year. This is the same issue as using automatic detection of terrorists - Its one thing to match/no match a known ID (eg biometric passport) to a person, its another to match every passer by to every known terrorist.

Coming back to chemical detection, this level of sensitivity will mean that every person who uses GTN for angina (commonly known as "Anginine" tablets or sprays) runs the risk of coming up positive. This amounts probably about a million people in US, and lots more elsewhere in the world. GTN (used in microgram doses in the treatment of poor blood supply to the heart; the precursor to a heart attack) is actually tri nitro glycerine, and is just a wee touch explosive in larger quantities.

Just my 2c worth.

Michael

Re:Vulnerable to a "chaffing" attack?

[jigyasubalak]

On the other hand, seems like, they are depending too much on residues left on the luggage by the handler who loaded the explosives. Couldn't it be a possibility that the bombs(what else?) have been neatly packed and the luggage loading handler hasn't come across any residue? Or let's say it's an assembly line where the next handler who hasn't touched the explosive closes the luggage.

These people are so very much more insightful than an ordinary man on this subject. What are the chances they'll give their game away when you do public announcements on the advancements of explosive detection??

Re:Vulnerable to a "chaffing" attack?

[commodoresloat]

Isn't that a *huge* hole in any "super sensitive" chemical detection system?

Hmmmm... chaffing, super-sensitive, huge hole.... is this a subliminal advertisement for condoms?

Re:Vulnerable to a "chaffing" attack?

[6th time lucky]

I must look a little shady, because I *always* get 'randmonly selected' to be drug/bomb 'sniffed' at airports getting swabbed and waiting for a machine to go beep.

The thing is i work in a chemical lab and often handle ammonium nitrate (plant tissue cell culture, great ingredient for pipe bombs i am lead to believe) yet have never had the machine go haywire at me. I always mention this to the nice security guys before the test so i hope they wont shoot first if it ever does go beep beep beep beep...

Interesting point about the nitro glycerine too...

Re:Vulnerable to a "chaffing" attack?

[6th time lucky]

The local law enforcment started putting drug sniffing dogs in the major train stations here (A few places around Australia). The resulting protest had people squirting passers by (and walkways so people would walk through it) with bong water thus contaminating everyone there with dog-detectable levels of drugs...

Not that i condone drug use, but that type of attack obviously does not require all of one's brain cells...

Re:Vulnerable to a "chaffing" attack?

[Vellmont]

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?


I think a few molecules might be a bit of an over statement. Nitroglycerin has a weight of 227g/mole. A mole is 6.02*10^23. So one molecule of nitroglycerin weighs 3.77 * 10^-22 grams.

A picogram = 1*10^-12 grams.

1*10^-12/(3.77*10^-22)=2.65* 10^9, or 2.65 billion molecules. That's a ways from a few.

I think your point still is valid though. Could someone contaminate an area such that it couldn't be cleaned sufficiently? My guess is it probbably could be. You don't have to get rid of all the material, just enough so that you're below the level of detection.

Re:Vulnerable to a "chaffing" attack?

[Sexy Bern]

http://www.airportguides.co.uk/guides/heathrow/fac tsandfigures.html

64e6 passengers per year = 175,000 passengers per day.

Pretend these are all commercial 737s with 130 seats, all filled. That's 1349 flights per day which is pretty much one per minute (1440 minutes per day). Having once stayed with a friend whose house was in the flight path, that seems feasible!

Plus, London has "three" major airports - Heathrow, Gatwick and Luton (not really London, IMHO). There's also "London city airport" too, but that's pretty small.

Re:Vulnerable to a "chaffing" attack?

[ChrisA90278]

When you install the machine and periodically thereafter you would "null" it. That means you adjust the needle to read zero when there is nothing in the detection chamber. I used an oxigen sensor resently. The first step is to expose it to just plain air and adjust it to read 21% (air is about 21% oxigen, 79% nitrogen) After doing this it can detect very small amounts In both cases you have to tell the machine "This is the normal background." After this the machine detects changes.

Re:Vulnerable to a "chaffing" attack?

[pe1chl]

The whole principle of the detector is that it is not possible to clean it sufficiently...
If that were possible, the terrorists could clean their stuff before having it checked.

Oh great...

[Dr. Zowie]

now, when I fly, I have to worry not just about whether I handled matches or toy cap guns or went to the shooting range in the last 24 hours, but also whether my neighbor, my dog, or the taxi driver handled any nitrate-laden deli meat in the last month.

Re:Oh great...

[fishbowl]

>I thought carrying an unloaded pistol in your checked baggage was legal anyway.

It depends on your destination, as always.

You cannot fly into Massachussetts or DC, for instance. But I routinely take firearms on trips from Arizona to Oregon. There's a little drill at the baggage check, where you have to say certain words verbatim; the weapon has to be unloaded in a locked container, and any ammo has to be in the packaging as it came from the factory and also locked.

There's always a little stressful situation at the counter where you have to take the gun out of the box, show them it's unloaded (open the revolver, rack the slide, etc.). Invariably, there's someone in line behind me that freaks out on this.

Then you have to carry your bag to a special X-Ray line, and tell the X-Ray guy what's in there. They make sure you have the only key.

At the destination, nobody ever seems to care, or know, what's in the suitcase, and rifle cases are always just piled with the golf bags.

But there's nothing to it. Get this -- in AZ, it's perfectly legal to wear a pistol openly in a holster on your hip, in the airport, all the way to the first checkpoint (but absolutely not past it!).

Re:Oh great...

[Walkiry]

>Are you sure a mass spectrometer would distinguish between ammonia compounds (in Urine) + Potassium Nitrate and a high grade explosive like Ammonium Nitrate?

The instrument? Yes. It all depends on what the software used to control when the detector beeps with a positive does. Let me explain.

I work at a biotech company and we do a lot of mass spec stuff. The instruments we have are extremely accurate; the Q-tof mass spectrometer, for example, can resolve the isotopic peaks of a protein fragment very easily (difference of 1 neutron), and you can get an accuracy of some 50 ppm (parts per million) between the reported mass of the molecule and the actual mass of it. Trust me, the instrument will distinguish between the different compounds, they'll come as clearly separated peaks in the spectra. They're amazingly accurate machines. The next generation of Q-tof claims it'll reach an accuracy of 1 ppm and lower.

The problem is what the software will do with the information it gets from the instrument. Is it programmed to go off when it detects specific molecules (meaning a specific mass plus the typical isotopic distribution of said molecule)? Will it go off if it detects any nitrogenated compound (these instruments can "break" large compounds when in MS/MS mode, it's the basis for protein sequencing when using Mass Spectrometers)? Will the list of "compounds that can make the alarm go off" include compounds that are typically found in places other than explosives "just in case"? The limiting step will be the rules used to report a positive, not the instrument itself. Or said in a different way, how paranoid the person making the rules really was.

Re:Oh great...

[smurd]

Firecrackers are filled with flash power which is a mix of Potasium perchlorate and aluminum powder (dust), Illegal stuff made by Jed and Clem in the barn sometimes contains Potasium Chlorate instead, it's unstable but they don't care (it makes a slightly louder bang). There is no sulphur.
I don't know what is in caps but it sure is not ammonium tri-iodide. If it was, everything near it would turn purple! ahh, the joys of a misspent youth. It would make it easy to tell though as it won't wash off.

Good luck to explosives manufacturers...

[DrInequality]

Good luck to explosives manufacturers - there go your chances of ever flying again!

Re:Good luck to explosives manufacturers...

[JavaRob]

Good luck to explosives manufacturers - there go your chances of ever flying again!

Nonsense. It's not like they'll tackle you if you set off the machine -- you just can't go through the new super-fast check, so you get shunted into the line with the explosive-check wipe tab thingies and/or manual bag search... just like we *all* have to go through currently in most airports.

It's all about speeding things up for most people -- yes, there are some who won't benefit, but they likely won't be worse off.

Re:Good luck to explosives manufacturers...

[tmittz]

Interestingly enough, most people who deal with explosive, pyrotechnics, etc, are registered with the Bureau of Alcohol, Tobacco, Firearms, and Explosives. My uncle does fireworks shows for Disney, and he often gets flagged by immigration whenever he enters or leaves the country. It typically means a bit longer delay than the unflagged person, but I imagine it would also give some measure of protection were his luggage to be detected to contain traces of explosives.

Re:Good luck to explosives manufacturers...

[ozmanjusri]

Good luck to explosives manufacturers - there go your chances of ever flying again!

Not just manufacturers. In Western Australia, and presumably other parts of the world, most mines operate on a fly-in fly-out basis. People work onsite for a fortnight, then fly back to the city for a week to live with their families. A fairly large proportion of those are exposed to explosives or their by-products pretty much constantly while they're on site.

The existing sniffers don't appear particularly sensitive. A few months ago I flew to site, worked with the shot crew for a day, including contact with ANFO emulsion and primers (TNT), then flew home. I expected the detector to pick it up, so I kept the work order on hand to explain the situation to security, but it didn't happen - not a peep.

Other (ab)uses

[Kill Switch]

This is certain, just like the current TSA baggage screening, to be used to justify unlawful searches for drugs and other contraband. In fact, just like those baggage searches, this will undoubtedly become the #1 use of this technology, in fact I would bet good money that it is part of the intent of the people funding the development of this stuff. Just wait and see.

Quickest Means Possible

[Namronorman]

People fly because they want to go somewhere as fast as possible. With recent rules and regulations regarding airports, it's been becoming slower and slower to fly anywhere. Perhaps with the advancement in technology such as this, we can slowly relieve the stress of having to fly somewhere.

Re:Quickest Means Possible

[tgl]

No kidding. My recent business trips have mostly been Pittsburgh-to-and-from-Toronto. Door to door is about seven hours if I drive, and six hours if I fly (compared to about four hours before 9/11). Any more BS added onto the airport security check, and they lose this passenger permanently.

Oh, this should be fun.

[DrEldarion]

Expect every airport to be shut down for a week after the 4th of July.

Skunk Analogy

[tempest69]

The overload attack does have some merit. However it wont be "for all time" or even close. The best analog would be a skunk, their odor is detectable to humans in similar quantities. Thier odor is really offensive in higher quantities. However the smell of skunk can be cleaned to a reasonable level in a short amount of time, depending on what got "sprayed". For instance a couch, your gonna have to pitch it, the smell is there for good. If it's your dog, you might try tomato juice before pitching the dog.

So what I'm saying is that it can be blasted, but the recovery time should be reasonable. That means that the airports will need to take some precautions like not having big fluffy couches around that will carry the "smell" for months.

Of course I am not a chemist, I just felt like having a Cliff Claven moment.

Storm

Re:Skunk Analogy

[Velox_SwiftFox]

Thank ghod my couch isn't as interested in attacking skunks as my dog is.

Re:Skunk Analogy

[wowbagger]

First of all: you don't use tomato juice as it is ineffective. The best way to neutralize mercaptan is to use a mix of baking soda and hydrogen peroxide solution, which will oxidize the mercaptan and destroy it, without staining whatever you are cleaning.

Now, as for the explosive detector: I have a real problem with this, as if it is so sensitive as to be able to detect explosives after M. Random Terrorist has carefully cleaned up, it is probably sensitive enough to trigger on the residue left on me if I have done some home construction with my powder activated nail driver - which uses a .22 blank to drive nails into concrete.

It will probably also trigger on any heart patient using, or even carrying, medical nitroglycerin. So, obviously, the next bunch of Al Qeidea terrorists will all have very convincing papers indicating they are heart patients.

I'd say it's a good thing

[JavaRob]

Yes, it's vulnerable to false positives -- for example, some construction workers are going to have to go through the slow way every time they fly.

That's okay, though -- the positive thing here is that the initial check can be made much much faster. Most luggage and most people can just be zipped through (they'll hardly need to stop walking!)... which leaves more resources available to help the inevitable false positives get processed in the old, slow way (with the little explosive-check tabs, or a search by hand) as efficiently as possible.

That's what matters, isn't it? Speeding the whole thing up, to make a reliable screening feasible.

Re:I'd say it's a good thing

[mgv]

Yes, it's vulnerable to false positives -- for example, some construction workers are going to have to go through the slow way every time they fly.

That's okay, though -- the positive thing here is that the initial check can be made much much faster. Most luggage and most people can just be zipped through (they'll hardly need to stop walking!)... which leaves more resources available to help the inevitable false positives get processed in the old, slow way (with the little explosive-check tabs, or a search by hand) as efficiently as possible.

That's what matters, isn't it? Speeding the whole thing up, to make a reliable screening feasible.

Well, if it was used sensibly, that would be ok.

The risks are still two fold:

1) If the rate of false positives is low, alot of people will get through quickly. However, if you are one of the false positives, you may well get a very bad deal at the airport. Having been singled out on one trip to the US for no apparent reason (Probably because I took a "one way" flight so maybe they thought I was not planning to return!) I can assure you its no fun if you end up on the wrong end of a statistical test.

2) If there are too many false positives, people get blase. After all, how many people in the history of all plane flight have put explosives on a plane? A few dozen maybe, probably less than 100 all up. But any test will likely have many more false positives, and this will mean that these people get ignored.

3) You may still be using the wrong test, and get falsely reassured. After all, the September 11 hijackers would have passed a chemical detection test, so they would have been fine to board, no? Again, the real problem here wasn't that the test systems failed, it was the human management of the system - people weren't serious enough about the tests that were already in place.

So, you end up putting alot of money into doing something that will help very few flights, incovenience a large total number of innocent people, and possibly not protect the public at all.

After all, 3000 people died on September 11 due to a rare incident that is unlikely to ever happen again. 3000 people die every day in road accidents around the world. Which do you think gets society the best return for its time and energy? Yes, we have to stop terrorists, but just how far is it worth going here?

Michael

Re:I'd say it's a good thing

[theLOUDroom]

people weren't serious enough about the tests that were already in place.

No, the REAL problem was a policy of giving the hijackers whatever they wanted. Even with warnings that an attack like 9/11 was being planned, they were not changed.

There's simply NO WAY you could hijack a loaded 747 with a boxcutter today, you'd have every able bodied person on the plane on top of you in no time flat.

The flaw was not that they got box cutters on the plane, it was a flaw in our policy.

Even pre-9/11 the same thing would have never worked on an El Al flight....and not due to their better security either, simply due to a difference in their policy and attitude dealing with hijackers.
Everyone on the plane would have immediately understood that their own lives were at stake and acted accordingly.
This whole fuss about nail-files and the like is just nonsense.
The problem was, and still is at the top.

Re:I'd say it's a good thing

[Jardine]

El Al??

Israeli airline.

Hooray for Increased Accuracy

[OpenGLFan]

The last time I flew it was from a friend's outdoor wedding. Apparently the chemical sensors didn't like the outdoors-ness of my shoes, and because I was flying from scenic Colorado the security officers were used to this.
TSA Agent: "Been outdoors much? Hiked through the woods?"
Me: "Yes, some friends had a wedding in the middle of a field."
TSA Agent: "Thought so. Happens all the time."

They took my shoes and, after they failed to go boom, brought them back. I'm not bothered by this at all, but I wonder how many false positives people in these places have to deal with. Current detectors use neutron activation to detect the nitrogen in explosvies and, apparently, fertilizers used by the hotel grounds staff. Hopefully this will fix that particular problem.

Defeatable by multiple wrapping?

[Michael Woodhams]

Here's a possible countermeasure.
Construct your bomb. Shrink wrap it in plastic, taking care to get as little explosive residue on the outside as possible. Take it away from the bomb construction area, and wash the outside with strong soap etc. Give the result to another person.

They take it to somewhere clean of explosives residue, shrink wrap it in another layer, and carefully wash it, then hand it off to a third person who repeats the entire process again.

If you can reduce the explosives residues detectable by a factor of 100 or 1000 each time you do this, it can't take many iterations to reach undetectability - so long as the plastic is impervious to leakage. (Of course, then you need some way to program your hermetically sealed bomb. Also, you've forced many more people to become involved, which greatly increases the chance of betrayal before the bomb reaches its target.)

If this is practical, it must already have been tried to defeat drug-sniffing dogs. Does anyone have any ideas?

Re:Defeatable by multiple wrapping?

[Anonymous Coward]

Does anyone have any ideas?

Yes. How about not trying to get any of the rest of us involved in your terrorist activity?

Re:Defeatable by multiple wrapping?

[(negative video)]

Construct your bomb. Shrink wrap it in plastic, taking care to get as little explosive residue on the outside as possible. [lather, rinse, repeat]

Typical wrapping materials are rather porous, and several important explosives diffuse to some extent even through nonporous plastics. It is possible to seal explosives, but you have to really know what you are doing and even then a single microscopic dust particle can tip off the detector.

Regarding the article, nanogram sensitivity (a trillion molecules of TNT) is utterly unimpressive. The vapor pressure of most explosives is so low that you need femtogram sensitivity to directly sense vapor. For an explosive like RDX that has an absurdly low vapor pressure, you really want attogram sensitivity (about a million molecules). You can heat up dust and surfaces to vaporize more explosive, but with a mass spectrometer you then run into a problem with selectivity: many ordinary boring compounds will have the same molecular weight as the explosive--the signal will be swamped by the noise. (Hmmm ... the article says they're using clever ionization, and tandem spectrometry. That helps a lot, but they still have a hell of a problem to solve.)

The article says "'If you tried to detect a particular compound out of a mixture of thousands of different substances, you might begin to see the limitations of this method,' Talaty said. 'But real-world explosives are not that complex.'" What, people walk through airports with purified blocks of luggage? No! You get a suitcase drenched with sweat (which includes urea), solvents, ammonium nitrate from natural sources, perfumes, plasticizers, plastic monomers and short chain polymers, various mineral oils, a whole boat-load of volatiles from living things, and many more. The background signal is a freaking nightmare. I work in the explosive detection field, and I sure wish it was as easy as they say.

Are people that dumb?

[Cave_Monster]

I wonder as to how useful this technology will be in the fight against terrorism. If you were a terrorist, would you carry your kit with you on the plane or would you aquire all the materials locally when you arrive at your destination? I imagine crime networks who plan to set off bombs have their own stockpile of ingredients that they get from their own country and build them when they need them. Or am I completely off the mark and some regions don't have access to certain materials and need to import/smuggle them?

Re:Are people that dumb?

[TwentyLeaguesUnderLa]

Not necessarily that hard pressed. All you have to do is explode a reasonably sized bomb in the enormous line of people in the airport that is waiting to get through security.

Even faster and cheaper

[MiKM]

Fire. In all my experience as a pyromaniac, it has quickly and with 99.99% accuracy told me whether or not a substance was flammable.

Re:Even faster and cheaper

[KiloByte]

Hmm, you never tried to make a bonfire then, using (reportedly) flammable wood.

Awareness of recent world events

[caitsith01]

I'm surprised - very surprised - that there's no reference to the recent bombings in Bali in the article post. I mean, an article about instantly detecting explosives, three days after a serious terrorist attack... I can't help but feel that if it had been Hawaii and US citizens killed rather than Bali and Indonesian/Australian citizens killed this link would have been made.

Anyway, this is an interesting development, but should not lead us to stop traditional methods of bomb detection, particularly searches and x-rays. These machines sound wonderful *so long as* you are using an explosive with which they are familiar.

Sorely Needed

[evil agent]

Not at airports, but subways. A local news station did a report on the lack of security in Chicago's transit system, the CTA. According to the report:

"More people rode the CTA today than will pass through O'hare and Midway over the entire Thanksgiving weekend. Yet the feds only provide a penny per passenger for security on buses or trains... compared to seven or eight bucks for each plane passenger."

Doesn't really make sense, does it?

Mine Workers

[adoll]

I work in a mine. Nitrate laden dust is generated each day during the blast, and that dust gets everywhere and on everyone. So I have explosive residue in my clothes, hair and (probably) luggage.

Guess what happens when my crew walks into the airport to fly into the minesite for our two week shift?

-AD

Re:Mine Workers

[fishbowl]

"If you declare that before you went through security, I'm sure they would just let you pass through after a peekinto your bags."

Oh, no, not at all.

*Nothing* you say to TSA people is going to hasten your experience. I have a similar problem as the miner's. Nitrate residues off the scale from my bag, due to my work environment.

Do not overestimate the level of intuition of security personnel or cops, ever. Anything you try to say to them will merely be regarded as suspicious.

The last time I flew, I had to deal with two different people who did not speak English... at Logan.

Another thing to consider... Just about the entire TSA staff has been hired in the last 4 years, and I'm being generous with that. For many of them, it's their first job after getting their GED. Don't expect them to regard ANYTHING you tell them as anything but a threat.

Nah

[JavaRob]

This is specifically about *airport* security. It's about keeping the planes safe. A terrorist seeking to blow up an airliner would have a tough time if he acquired his supplies at his destination.

Of course, this brings up the point that even if we *did* manage to make planes super-safe, it remains simply impossible to protect all of the other soft targets all over the country. There are so many legitimate uses of explosive materials and the ingredients thereof that they can't all be secured, and any place that people are in large numbers is a potential target (including any school, stadium, office building, church, theater, etc.)... BUT Americans are nervous about planes after 9/11, so even though seeing the same attack again is unlikely, it makes constituents feel safer if we pump lots of money into airport security.

It's a shame that this is how we go about "waging the war on terrorism", but that's how the world works.

No, not really...

[xanthines-R-yummy]

This is basically a portable mass spectrometer which is very very very accurate as well as sensitive. It's so accurate, it can give the identities of proteins as well its sequence. Now, this "portable" (I use quotes, because its as portable as mass spec machines can be) model probably won't be THAT accuarate, but probably more so than any other machine. It would be hard to get false positives out of this thing because of its accuracy.

As for chaffing. I don't think this machine was meant to analyze the atmosphere of the entire airport. You just swab the bag and run it through the machine. There are ways to make the readings meaningless, but this would indicate some fishy behavior and cause for "other" means of investigation (ie "Bend over, son.").

This would be a real boon for forensic science in general, if they've managed to make one for a relatively cheap price in addition to its size. Now you don't have to wait for the lab, you can bring it with you.

Re:No, not really...

[Otto]

As for chaffing. I don't think this machine was meant to analyze the atmosphere of the entire airport. You just swab the bag and run it through the machine.

So when some guy spreads a lot of explosive dust all over the lobby, and you set your bag down and pick up some of that dust, then the machine will detect it and suddenly you've got a rubber gloved finger poking your ass?

Re:No, not really...

[fishbowl]

"You'd hope the screeners would wonder why they suddenly started getting a 100% hit rate and figure it out."

You're overestimating the intuition possessed by law enforcement and security people.

TOF and chemical ionization; also, another article

[Wilson_6500]

Just in case there are any chemical physicists reading this...

Assumedly, if this system is small enough to be backpack-sized, it's not a time-of-flight mass spec... right? The article's short on details on the actual mass spec--they seem to focus on their ionization technique more than on the spectrometer itself. But, then again, I guess that's where they're focusing their research.

I'm not too impressed by this "reactive chemical spray" system, but maybe that's because I'd be more concerned with airborne rather than adsorbed/adhered molecules. It seems needlessly destructive to be spraying corrosives onto a person's luggage, unless we're talking, like, microgram quantities--although if you're just taking off a few molecular layers, and if the reactive components are rarefied in a less reactive gas, maybe it's not a big deal. Still, couldn't the same sort of "wipes" that you see used with modern airport ion mobility spectrometers be used to spare travelers from being exposed to these "reactive" compounds? Too, it seems a bad idea to require that airports keep machines sitting around in terminals with cylinders of reactive gasses. Once again, the quantities one would be dealing with are what concern me.

They mention that their system suffers low selectivity. Selectivity, from what I understand, is pretty important in other fields, like nerve-gas detection, for instance, in order to force down false positives. What's keeping their system at a low rate of false positives as they claim?

I suppose I could read their papers; this article really is just a press release, after all. Being a lasers sort of guy, I guess maybe I'm just biased towards photoionization.

Also, even though this isn't really germane to my post here, I found another press release here is an article from just about a year ago that talks about this same DESI system.

I dont like bombs either but

[the_REAL_sam]

Has it ever occurred to you that the war on terror's refined capacities to detect explosives could also be used to suppress a "rebellious" majority population? (that is to say, to enforce a dictatorship in the USA?)

Just pointing out that the Bush administration has made more war against civil liberties, privacy and personal freedoms than any administration in my lifetime, and that Bush's election really looked like it was tampered, and that the 911 incident LOOKS ALOT LIKE HITLER'S RISE TO POWER. (read about the BURNING OF THE REICHSTAG)

http://www.shoaheducation.com/reichstag.html

The patriot act is just that -- a bunch of right wing police state warmongers taking away our privacy and then ACTING as if they were patriots in the process. That is to say, the patriot act is just that: an ACT.

And terror suppression in Iraq would also train the American military to suppress pro freedom American partisans.

To be honest, the term "homeland security" just makes the country feel less like my own home. It has a vague nuerolinguistic programming sound to it. It sounds antiforeign and hyperguarded. For starters, no American uses the term "homeland."

I really don't like bombs, but if the govt turns against us then those bombs detected with the new tech would just be the "friendly" ones.

Re:I dont like bombs either but

[kmac06]

You're insane. Absolutely utterly insane. You say the election looks tampered (which one? any evidence), imply that Bush caused 9/11 so he could solidify his power (he was already the President) and that he started the war in Iraq to train the troops to start a totalitarian state here.

You're absolutely batshit insane.

Re:I dont like bombs either but

[bhmit1]

Has it ever occurred to you that the war on terror's refined capacities to detect explosives could also be used to suppress a "rebellious" majority population? (that is to say, to enforce a dictatorship in the USA?)
[Cut the rest of the political rant]

How does this stuff get moderated up? People need to remember that driving a car is a privledge, not a right (and judges will be happy to remind you of that after you break a few driving laws). Similarly, when you get on any form of mass transportation (airplane, subway, train, etc), you subject yourself to the rules of that mode of transportation. Yes, it would be easy for a group to skew those rules to discriminate, so we need to keep an eye on our elected officials. But who in their right mind is defending someone that brings a backpack or shoe filled with explosives onto a plane or anywhere else? All I ask is that you treat the person with respect until you know for sure that it's some kind of explosives and not "yet another false positive."

The world is a half decent place when everyone is doing unto others as they would have done unto themselves. It's reasonable to defend mass transportation when there are some crazy folks that want to kill a lot of people. It's also reasonable to figure out why someone is so upset that they would get that pissed off at us to see if there's some way we can get along better with our neighbors. But we should be able to do that without the political rants.

Re:I dont like bombs either but

[bhmit1]

Has it ever occurred to you that the war on terror's refined capacities to detect explosives could also be used to suppress a "rebellious" majority population? (that is to say, to enforce a dictatorship in the USA?)

If every time that something is put into place for the public safety or other benign purpose someone shouts "dictatorship", how many people will be paying attention when our civil liberties actually are taken away?

Re:worthwhile ... ?

[fishbowl]

>Someone remind me what the point of this whizz-bang technology is again?

High explosives are not exactly stable.

Your plan will not really keep the volatile materials fully *inside* the suitcase.

Any kind of bomb worth using is going to be pretty noisy, chemically speaking. You're pretty much going to have a cloud of nitrates around you. If you've got enough of an oxidizer in your bag to be an effective bomb, it's going to be very difficult to keep it from being detected.

You could probably seal an organic explosive like C4 or TNT well enough to avoid detection by the swab test (which is looking for nitrates, sodium chlorate, etc.) but those have an obvious x-ray signature.

I sometimes work with my laptop in an environment that has all kinds of lawn and garden products (e.g., fertilizer), and if I take that laptop through security, they swab it every time, it comes up positive (!) and I get to explain to them why (!!). More than once, I've had to endure questioning by several levels of security people, and once, they made me sign something declaring that I didn't have any explosives (like that would matter?)

it seems

[ColaMan]

It seems to me that you could certainly circumvent this easily enough, with just some social engineering. Carry a lot of sniffer-activating things in your luggage. Travel 15 times on the route, or until you reliably know the security people.

After 15 times, the conversation goes like so:

You: "Hi Steve."
Security: "Hi John."
Detector : beeep! bip! beep! bip! beep! BEEEEEEEP!
You: "Damn detector. Can't they tone those things down a little?"
Security: "Every time you go through, these things go off."
(opens luggage)
Security: "Cheese, fertiliser, and trinitite. Again."
You: "Well, a man's got to earn a living some way. Isn't there some form or something I can fill out to get out of this?"
Security: "Nope. Everyone gets checked."
(closes luggage)
Security: "Off you go."

Travel 15 times without the bomb so everyone gets to know you.
The 16th time, travel with the bomb concealed somewhere in your luggage, but
leave the cheese , fertiliser and trinitite on top. Odds are pretty good that you'll get on that plane.

Rubber? Here's the new glove...

[ari_j]

Dude, you are entirely out of touch (bad pun, down!)...the Homeland Security Act changed the type of gloves that are used for airpot cavity searches. The new gloves are not exactly rubber.

It's posts like these...

[Anonymous Coward]

It's posts like these on /. and around the Internet that are starting to push me further and further away from the left side of politics and /. itself. For instance this story is about a specific technology used to find traces of chemicals. It doesn't have an inkling of political skewing about it.

So now we have the parents post (currently modded +4 interesting) who claims that this new technology could be used to suppress the population. The parent never bothers to extrapolate on how this technology in the article could be used for the purpose of suppression of course. We are just supposed to accept the fact that it will sometime in the future under the guise of a totalitarian government. Notice how we are supposed to just accept his didactic terms the parent lays out? That's called propaganda.

The parent is why I'm moving away from the left. It seems the lefts (and /.) groupthink supports irrationality, conspiracy theory and poorly thought out historical analogies. Is the Bush admin doing a bad job? Yes I totally agree. But I don't think we are ever going to be taken serious in our claims or actions to change the system when some of our fellow progressives are completely irrational in the way that they present themselves.

The parent post is pretty offtopic from the subject at hand but I had to respond.

Many airports are carpeted; other targets

[billstewart]

Many airports are carpeted, at least in some areas, and cleaning up moving walkways is probably not that easy either, especially the rubber-tread ones. Then there's the luggage rack on the parking shuttle busses... If you've got a super-sensitive machine, and somebody wanted to overload it, there are way too many opportunities.

NH4NO3 == Explosive == Garden Fertilizer

[evilandi]

Great, so the system can detect farmers and gardeners at longer ranges?

The UK/France Channel Tunnel security checks use guards with cotton gloves to wipe around the inside of passengers' cars. The gloves are then analysed by computer- this means a complete explosives search can be done in two minutes, rather than having to rip the car's body panels apart. Unfortunately, this has a huge false positive rate for anyone who's been in contact with fertilizers; my uncle, who is a keen gardener, got questioned at the end of an SMG for quite a while before he mentioned that he'd been carrying bags of nitrate fertilzer in his trunk just a few days prior.

Whilst that's inconvenient for gardeners and farmers, its also a safety risk for the rest of the passengers; after all, it gives a convenient alibi for saboteurs. I certainly wouldn't want to board a train in the same carriage as the Falls Road Allotment Society.

These toys provide useful indicators of where to concentrate resources on, but they should never replace good old fashioned trained security staff.

Save the money from security...

[tazanator]

I had a discussion long ago with a person that had a great idea. If you was going to fly, ALL lugage was shipped by truck a few days in advance. When you arrived to get on the plane, you are lead to a room, stripped of all clothes ran thru a "decontamination room" and given a disposable jump suit. Everyone flew in these jumpsuits with no other items allowed on the plane. (I think flying naked may be even more secure but the view would be SCARY!!) but with all lugage shoes and clothes shipped on ground based trucks and every passanger flying without even their own clothes, there would be safty in the air. Course I would prefeer even fewer planes in the sky (I like to watch the stars, not planes at night.)