Slashdot Mirror
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."
I heard on the radio today that dynamite looked like red sticks.
Like I'm going to let airport security subject my laptop to "nitrogen nuclear quadrapole resonance". Sounds like an electronic death wish to me ;) .
SO will it detect Cocaine, herion, anthrax, flour? What if I add some gun powder to my Coke?
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?
Regards,
MBC1977,
Cool! When can the new technology allow us to walk through the security with dignity again?
In Soviet Washington the swamp drains you.
Radio waves! So, they'll send a signal out that'll trigger the bombs those assholes made, blowing those assholes up while they're still in their caves?
That's easy!
All you have to do is go through all the frequencies being used by the radio triggers and send a "detonate" signal on each such frequency.
I guarantee you'll detect the explosive when it goes off...
Hey, it's better than having it go off on the plane, right? :-)
Use 'slashdot stuff' in the subject line in any email you send me if you want to get past the spam filter.
I remember hearing warnings about having transmitters near my explosives, something about accidentally triggering professional grade gear;
Exposing high strength radio waves to homemade devices might result in detection by detonation.......
Unix, an obscure operating system developed by bored researchers in an attempt to get a better game playing experience.
It appears to be a slightly more advanced system than SNUPA http://www.abc.net.au/quantum/stories/s112369.htm developed at the University of Melbourne, which I believe didn't differentiate between different explosive compounds.
A game has objectives and is competitive, anything else is just play
Nothing (plausible) can detect everything that might be explosive, but it would seem this targets the most easily-obtained explosives and should raise the bar significantly in terms of the technical competence it takes to defeat the security measures.
That said, it would seem to have a ways to go before it's practical.
I am the one true god. However, as an atheist, I don't believe in myself. I guess I have a self-esteem problem.
Quo usque tandem abutere, Nimbus, patientia nostra?
A little oxidized iron, a little aluminum powder, a tiny amount of binder, press, and you have the makings of some attractive plaques or statuary. A bit of magnesium wire and a battery and you have everything you need to start a large mass of aluminum burning. Spectacularly.
Good thing none of the Bad Guys have the brains of a flatworm. Or at least, that's what our whole air travel security strategy assumes.
Lacking <sarcasm> tags,
so this is called nuclear magnetic resonance spectroscopy.
Doing it with a gradient field and a special pulse sequence lets you get the
vibrational amplitudes of your protons based on their position within the gradient field.
That's what gets you MRI images. Before MRI images, nuclear spectroscopy was used to
resonate the "nucleus" of atoms/molecules/conglomerations of molecules at varying radio-frequencies to see if there was any resulting resonance and output RF (radiofrequency) signal.
Protons resonate at 2.4 GHz approximately (which is the frequency used in microwaves to resonate the H's in the {H}_2{0} molecules in your food and heat it.
that would make everyione undress, give them on orange jump suit and send all there things in a cargo plane to meet them.
Possible medicate them into a stupor.
The Kruger Dunning explains most post on
The above is so wrong that I don't know where to start.
...using explosions to detect radio waves.
https://www.eff.org/https-everywhere
And not all nitrogen containing explosives are white powders. :)
Computational Chemistry products and services.
It doesn't work for scanning luggage because RF at this frequency doesn't penetrate well.
Also helps greatly reduce the volume of checked and carry-on luggage.
Prototype mine detectors based on NQR have been built and tested. The signals are very weak, even with tens of watts of excitation which makes this a difficult techique for practical use. See http://maic.jmu.edu/JOURNAL/9.2/RD/williams/willia ms.htm for more info.
Ron Sager and Alan Sheldon of Quantum Design used a SQUID in 1992 for detecting the NQR response of ammonium perchlorate (~38kHz), so the Japanese group isn't even the first to use SQUIDs for NQR...
A Shadeless room is a brighter room.
Even if it doesn't find the explosives, I'll bet it's great at finding the detonators.
I have a much simpler method: if america doesn't like country X it follows that X has explosives...
The MAFIAA is a bunch of mindless jerks who will be the first up against the wall when the revolution comes
Having yet another nitrogen explosives detector is not very interesting. It does not solve the problem of peroxide and oxyhalide based explosives, the former having already proven to be popular with terrorists, and both types having seen limited military application in the 20th century.
A truly effective explosives detection technology will need to target a broader range of high explosive chemistries, and preferably not the same ones over and over. When the corner store is out of C4, people bent on blowing things up will find something else.
And how about explosives without nitrogen? I personally know two high explosives, which were successfully used in WWII and which doesn't contain nitrogen.
And I also know some other compounds that can serve as explosives and does not contain nitrogen or chlorine.
And I'm not a professional chemist, chemistry was just my hobby at school and high-school.
Not all "useful" or "effective" explosives are nitrogen based.
From TFA:
"Scientists in Japan have developed a new technique for sensing explosives in luggage and landmines."
Thank goodness - a safe way to tell if a landmine contains explosives. That'll save a lot of wear and tear on orphans.
guarding the planes. To hell with the people on the ground. Why do you think that security is set up in the MIDDLE of the airport? What if a bad guy wanted to kill people in the terminal? Wide open. That is why in Israel, the security is at the front gate., not the flight gate.
Now I won't have to deal with homeland security cutting open my 5lb bag of grits anymore when I leave The South for work.
Do not look into LASER with remaining eye!
You just have to send the correct frequency, and bam, it explodes!
Is not life a hundred times too short for us to bore ourselves? -Friedrich Wilhelm Nietzsche
Luggage probably does not burn very well. The suitcase and its contents are mostly fabric / leather / plastic of some type. ( think about what you packed last time... ) Most clothing has passed some kind of won't-sustain-combustion test, and that in the presence of lots of oxygen at or near sea level. Leather won't sustain a fire on its own. Plastics, who knows? But few are highly exothermic.
And add to that the fact that there is not a whole lot of air available in the luggage container - it's mostly luggage. Even if there is enough fuel to sustain a low-temp fire, it soon suffocates itself. The only jet that has crashed in the last few decades due to a cargo fire was because there was an oxygen tank in the luggage.
Also, according to federal law, all luggage compartments on commercial airliners are required to have fire-resistant walls.
You need to induce a very large magnetic field (relative to the nucleus) to induce NQR
.38s next to the boarding gate, for any interested adult to bring on board, just in case. (Another bin near the exit gate collects the unwanted weight afterward.)
I'd say there's the rub. I'm sure everyone here has seen the enormous magnets used in nuclear magnetic imaging, if only on the television. And at that an MRI patient has to sit still for half an hour. You can't take half an hour to scan a bag, you've got to do it in a second or two. So that means you need a truly huge, multimillion-dollar magnet, to collect your signal fast enough.
Sheesh. Much cheaper to just put a bin of loaded
After reading a little further, I see it can be done without the magnet at all. Now all I need is a /. rewind widget...
When are we going to bypass this whole mess and just invent the teleporter?
Oh Crap, I'm an optimist.....
As someone who uses NMR literally every single day and has taken graduate courses in the subject, let me correct a few major issues with your statement.
1) "Doing it with a gradient field and a special pulse sequence lets you get the vibrational amplitudes of your protons based on their position within the gradient field." In NMR (NOT MRI), gradients most commonly come up the form of gradient shimming, which is a technique for homogenizing the magnetic field applied to a sample. In general, gradient fields themselves are undesirable (for chemical analysis; different needs arise in imaging). More importantly, you are confusing IR spectroscopy (which observes molecular vibrations) with NMR, which looks at quantum spin phenomena in nuclei. Briefly, dipolar nuclei (those with an odd number of protons and even number of neutrons; 1H is the best such nucleus for signal/noise ratio due to its high natural abundance and gyromagnetic ratio) distribute themselves into two quantum spin states (aligned/opposed to the incident field) roughly according to Maxwell-Boltzmann statistics due to the slight difference in energies of the states. The energy difference is on the order of RF energy, and the quantized absorption of RF radiation of the exact energy of the state differential can induce a spin state transition. The exact energy required depends primarily on the intrinsic properties of the nuclei, but also slightly on the electronic environment surrounding the nucleus, which permits (in NMR) chemically non-equivalent nuclei to be distinguished in a molecule. More complex experiments (an acronym soup that includes experiments such as DEPT, COSY, NOESY, HETCOR, etc.) can be used to elucidate the entire structure of a molecule, including distances between atoms. MRI is based, broadly speaking, on the fact that the amount of time it takes spin-excited nuclei to "relax" back to the ground state depends on factors including their solvent environment. Hence MRI can easily distinguish between, e.g., water and fat, by carefully observing how long an NMR signal is seen from excited nuclei.
2) "at varying radio-frequencies to see if there was any resulting resonance and output RF (radiofrequency) signal." When resonance is achieved the incident RF is absorbed, not emitted. Applying "varying" RF is classical "continuous wave" NMR. Modern spectrometers (FT-NMR) use a broad pulse to excite ALL resonances simultaneously. As they relax, RF is emitted as you suggest, and the probe coils detect the decaying resonances of all nuclei simultaneously. A computer then does a weighted Fourier transform on the time-resolved data to convert from time domain to frequency domain, thus extracting the spectrum. CW spectrometers have been completely replaced by FT instruments due to much shorter experiment times, better signal to noise, and ability to run multidimensional experiments.
3) "Protons resonate at 2.4 GHz approximately (which is the frequency used in microwaves to resonate the H's in the {H}_2{0} molecules in your food and heat it." I don't even know where to begin. First, the proton resonance frequency is ENTIRELY dependent on the strength of the applied field. Hence the strength of the superconducting magnets in NMR spectrometers is usually measured by the standard proton resonance frequency in the magnet. For example, I usually use 400 MHz instruments, which means that the field is of such a strength that protons resonate around 400 MHz. I also have 500 and 600 MHz instruments available when I need greater resolution or signal/noise ratio. The primary difference between the instruments is the strength (read: size) of the cryomagnet. Furthermore, the highest power NMR commercially available recently was 900 MHz. I have heard that the major manufacturers (Bruker and Varian) have a 950 on deck, and it may now be for sale (for a hefty sum). They are still working on trying to reach 1 GHz. There are NMR spectrometers that have been reported to achieve the much higher 2.4 GHz resonance, but these are highly ex
Wouldn't it be difficult to detect small amounts of nitrogen bound in substances when your SQUID detector is bathed in the same substance you're trying to detect?
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Besides possibly denotating some explosive devices this technique can be tailed to detect Vista outbreaks.
>distinguish between different white powders
I would think that black powder would be more of a concern here...
There is nothing new about using radio waves for explosives detection. The navel research labs and russians have been working on NQR explosives detection for 40 years. Many other groups worldwide are also working on the technology. Two companies have products out and in airports, GE and QR Sciences, although currently the number of units deployed is quit low. The somewhat novel thing in the article is the use of squids. This is not entirely novel because the russian, GE and others have looked at this over the past 10 years. It is generally accepted that squids generally do not add much improvement to the signal to noise ration, SNR, in the lab, and add NOTHING to fieldable configurations of NQR systems. This is because the major noise sources are not the amplifier itself, but rather the intrinsic antenna noise, RFI (radio frequency interference), and induced ringing in the target item (shoes, baggage content, etc). Additionally the squids add significant cost, complexity, and reliablility issues. What this japanese group has done is all well and fine for research in a highly controlled laboratory environment, but it is completely unreasonable to tout this as useful in real life applications, much less presenting it as a breakthru.