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CO2 laser enables long-range detection of radioactive material

107 points by EA-3167 - 19 comments
adrian_b [3 hidden]5 mins ago
The free preprint of the research paper:

https://arxiv.org/abs/2408.13640

PaulHoule [3 hidden]5 mins ago
Makes me think of https://en.wikipedia.org/wiki/Ionization_chamber which can work at atmospheric pressure.
MisterTea [3 hidden]5 mins ago
The multiplier effect invokes this: https://en.wikipedia.org/wiki/Scintillation_counter
magnat [3 hidden]5 mins ago
> The team also used a CMOS camera to capture visible-light emissions from the microplasmas (...) The CMOS imagers, however, had to be placed close to the measured radiation source, reducing their applicability to remote sensing

How can it be called long-range detector, if literally the detector has to be placed at measured object?

adrian_b [3 hidden]5 mins ago
The detector using the scattering of the infrared light emitted by the laser is long range.

They have used a second detection method with a CMOS camera that detected the fluorescence of the plasma produced by ionizing radiation.

The second short-range method was used for comparison with the investigated method, to assess its efficiency.

ziknard [3 hidden]5 mins ago
Easily defeated by a large Tupperware container.
gh02t [3 hidden]5 mins ago
Kinda, but at least for gamma radiation (which is the main one you care about finding at standoff), the same radiation that induces the ionization these lasers detect will go right through tupperware and ionize the air outside, which will be just as detectable as long as it's strong enough to still produce enough ionization outside the tupperware.

Shielding the source with something that actually absorbs gammas like steel or lead is something that would actually render this laser detection null, but that's also true of conventional direct radiation detection methods too. No real way to find something that's not emitting something.

Regardless, this method is probably more intended for scenarios like nuclear accidents where you don't really have to worry about someone hiding the source from you. Though I still don't see that many applications for it even within that niche (and I did my PhD on finding radiation sources and currently work full time on it, so I'm fairly knowledgeable on the subject...), as there are a lot of limitations to this.

CamperBob2 [3 hidden]5 mins ago
Very interesting effect, but yes, the real imagination comes in when you have to explain how it might be used in practice.
SiempreViernes [3 hidden]5 mins ago
I think this is for the, now depressingly remote, situation where you want to verify that something at the end of a adversaries missile is really not a nuclear weapon because a treaty says that would be one too many.

In that context a way to measure radioactivity by non-invasive means is great!

Shame that a nuclear weapons treaty with limits and an inspections regime is more sci-fi than the technology needed to remotely verify the presence of a warhead.

ricksunny [3 hidden]5 mins ago
>Shame that a nuclear weapons treaty with limits and an inspections regime is more sci-fi than the technology needed to remotely verify the presence of a warhead

Well articulated. The early history of atomic weapons regulation hinges on precisely the difficulty of independent verification means (as well as judgements on whether or not an adversary would let you into their country without whack-a-mole style circumvention). I still think that verification technology is the main stumbling block. Neutrino detection is what I (and I bet ongoing orograms in the DoE) focus on for this purpose. We need to be able to figure out how to sense neutrinos order of magnitude more effectively than we can currently. Right now it feels like panning for gold silt with sieves as sparse as chicken-wire.

andrewflnr [3 hidden]5 mins ago
> We need to be able to figure out how to sense neutrinos order of magnitude more effectively than we can currently.

I don't see any reason to believe that's possible though. I guess I don't know how close we are to the theoretical limit, but anything made of atoms will feel like a chicken-wire sieve, right? Unless there's something big you/DoE know that I don't.

Animats [3 hidden]5 mins ago
Yes. 10 meter range, must have line of sight to the radioactive material. When does that come up in practice?
Terr_ [3 hidden]5 mins ago
Could it be useful in a nuclear-reactor context?

If the sensor is further away, it might be easier to maintain, have a longer lifetime, and could even be re-aimed to cover a wider area or identify where a specific hotspot is.

Depending on how l

notfed [3 hidden]5 mins ago
Erm... how?
ggm [3 hidden]5 mins ago
TSA will be buying.
keepamovin [3 hidden]5 mins ago
Lol I knew this was possible!
neuroelectron [3 hidden]5 mins ago
I'm no nuclear scientist, but doesn't this seem like a very basic way to detect radiation that we should have discovered before?
notfed [3 hidden]5 mins ago
There's no claim of a new discovery here, just an impressive feat of engineering. Remember that nuclear fusion is also pretty basic.
titzer [3 hidden]5 mins ago
> nuclear fusion is also pretty basic.

Get 'em hot and smash 'em is a remarkably effective method at multiple scales :)