How to find a tiny radioactive source while doing 70 kph | Hacker News Reader

How to find a tiny radioactive source while doing 70 kph

ansto.gov.au

134 pointsDrZootron81 comments

This is more of an ANSTO PR piece to promote a new piece of kit [1] based on a recent paper [2].

I'm guessing they loved the opportunity to field test this in a sea of global public interest.

What they're not actually saying is that the source in question could have just as easily been found using 1990s technology in a low flying aircraft at 70m/sec ( ~250 km/hr ) - once you get the target peaks (which were bright against the background) in a 70m square it's a simple matter to wave handheld detectors about to zero in on the capsule by the road.

Also of note "How to find .." is somewhat misleading is there is great deal of gloss here but relatively little substance.

[1] https://www.ansto.gov.au/products/detection-and-imaging-cori...

[2] https://iopscience.iop.org/article/10.1088/1748-0221/15/04/P...

[2a] https://sci-hub.ru/10.1088/1748-0221/15/04/P04014

> What they're not actually saying is that the source in question could have just as easily been found using 1990s technology in a low flying aircraft at 70m/sec

Well, yes. But it turned out, to everyone's relief, that the optimistic assumption held: the capsule was in fact still lying near the side of the expected road.

It could have gone another way - it could have been picked up and moved elsewhere by vehicle tyre, small animal or a human, in which case things would be much harder.

In which case an aircraft gives a better wide area search frame.

Also, things that are possible are frequently unlikely - bits of metal fall from road trains all the time, the near road side is littered with bolts bits of tyre, etc. They largely don't travel far for the most part.

Ergo: flying a plane on day one of known missing object would have been faster and cheap in the long run, provided more information, and been immediate leaving less time for the chance of a pick up and move elsewhere.

Waiting several days for the ANSTO group to roll up increased the chances of movement but provided a chance for them to take the glory and road test their new toy in the field.

It's a mixed bag of possibilities, and it's found now, so <shrug>, not much to see here.

There are no humans and basically no vehicles along a road like this. The chances of anything interfering with it are nil.

Good job, but a lot of the reports really exaggerate the size of the search area.

> in the formidable conditions of the outback...

> It’s fair to say finding a piece of equipment the size of a button in a vast desert was no easy task

Let's not go too far here. It was two metres from the road and they knew exactly which 1400km of roads to check.

I was rather baffled by so many sources claiming that this would be super difficult to find.

It seemed like such a simple task to drive up and down roads with some radiation detection equipment, log the data and investigate any hotspots.

Well, I guess it was? Or maybe I'm severely underestimating the complexity of this?

The problem was the unclear scope - it was not sure if the capsule didn't get stuck into someone's tire, an animal ate or played with it, or if it got damaged by a car running over it.

Well imagine if the pellet fell on the road, another car drove by and the pellet got stuck in one of the car's tire grooves. The car eventually makes it to a parking lot, or to the back of someone's ranch. Good luck finding it, short of monitoring hospitals for radiation poisoning patients.

Perhaps a nation-wide campaign to cover your phone camera lens with tape and then look for artifacts from gamma rays hitting the CMOS sensor?

Well, that's one way. Monitoring/surveillance cameras in hot spots in nuclear facilities are often known to have horrible fuzzy images (sometimes it's difficult to see what's being monitored).

It's an interesting question how close one would have to get for the CMOS sensor to register notably in this instance. Given the stated radiation signature of this sample it's likely one would have to get pretty close, so it may not be a useful technique.

I can't recall having read anything about smartphone CMOS sensors and radiation thresholds so I'd be interested in hearing from anyone whose knowledgeable about the matter.

You might as well make up a story about a kangaroo eating it and then someone hunting and eating the 'roo.

The odds for any one small object to get not only picked up but picked up and not tossed back out are astronomically tiny.

In some other thread I believe someone said with his known equipment, even if not occluded, a scan would take some seconds... so with that wouldn't have been to be that easy? So now not sure if normal.or amazing that they can do this with a 70km/h drive by?!

( Edit: https://news.ycombinator.com/item?id=34623782 sounds like not too amazing :) )

It's not too amazing.

Perth has a few companies that do this work for a living - as a grind job, flying contracts for an actuall million line kilometres of 256 channel radiometric mapping at anything from $7 to $15 AU per line kilometre for mineral exploration.

This has been ongoing for 50 years (see: Radiometric Map of Australia) and I'm slighlty baffled why a plane wasn't flown along the road on day one.

Realistic guesses are that all airframes were fully booked AND the national agencies wanted to shine and test their new gadget.

It's slightly complex gear to set up - but no more so than properly running the lines for a concert from pickups to to desk to foldback and main speakers, etc. If you can do one you can do the other.

Complicated is when you go and map some area in India near the Pakistan border and suddenly a surprise nuclear test happens beneath you .. which happened to one local crew .. but that's a whole other story.

I want to know this other story, I haven't found it by cursory search - what should I be searching for?

Pokhran-II was a series of five nuclear bomb test explosions conducted by India in May 1998, Pakistan responded with six underground nuclear tests at the Chagai and Kharan test site conducted fifteen days after India's last test.

It was all abit unexpected at the time and the US was interested to know how it came to be that Australians were present.

I am sorry I am not following the connection between Pokhran-II nuclear tests and Australia. Would you mind sharing some more information or a link maybe?

It sounds like a fascinating story indeed, but I can't find anything about it after a search.

True story, and these days you'd probably have to go to paper copies to find quotes from senior US defence | politicians expressing surprise at tests that seemingly came out of nowhere.

I dare say somebody might write it up well after retirement for release after death.

An Australian radiometric survey team were there at the time over the area during the first detonation .. and for the rest of the series.

Things got ... interesting.

Oh. and why were they there in the first place? On some scientific research field study / invited by the Indian government?

Ostensibly for a routine few hundred thousand line kilometres of geophysical survey in northern India for mineral exploration.

Contracted to a cutout company.

It just happened to be the first such survey in India and to coincidentally be at the exact place and time the area turned into an underground nuclear test site.

I would hazard that there is a good bit of transmission of shock waves from below to the surface, but it's ofc attenuated by the large mismatch in density at the ground air-interface...

How badly were they hurt? Were they hurt at all?

The plane was buffeted, the crew were unhurt, on the day.

Their diginity took a mild beating after landing and spending a month under quasi "friendly" house arrest by Indian troops who watched them gather more data and process it, compounded by questioning from US border agents in following years in transit, and offset by the joy of watch high caste Indian Geophysicists that insisted on being in the planes vomit on every end of line turn.

( It's a gut wrenching maneuver )

Telling them the planes weren't landing and they'd have to clean up their own mess "sparked joy", I believe.

I would buy a book about this in a heartbeat. Thank you for the story.

> the national agencies wanted to shine and test their new gadget

Exactly. After reading the press release and how they promote their device, I'm not so sure this wasn't deliberate.

My thought exactly

What I don't understand is, what kind of technology is it? It is obviously great. The technical explanation is not there

The simplest spectrometer is dark sealed tubes of doped sodium iodide crytals with a counter at the ends.

When an energetic gama burst hits a bit of crystal it flashes in a manner that gives up the energy .. over the course of a second and a few thousand events (normal background radiation) you have a spectrum [1].

You no have an indication of all the radiation all arounf the tube.

All around. With no indication of direction. Literally they could have come from anywhere, up, down, left, right, behind you, etc.

What we have here appears to be a vertical tube (or tubes) with mobile masking templates that rotate about and provide some axis of ingress information coupled with any energetic flahes that appear at the same instant.

There is some topographical statistics that needs to be performed and overall there are reduced signal levels (as some incoming gammas are masked and never make a flash) but you can end up with a positional image of where various radiation sources are in the space about the tube.

The other wrinkle they gloss over ('compressed', 'needs fewer counts') suggests (it's either obfuscated or I haven't read deeply enough) they have an eigen library of responses (ie. mean Australian background, Pure Potassium, Pure Uranium, Pure Thorium, Cs-137) baked in to facilitate faster recognition of spectrum patterns.

It's a pattern matching in N^256 type problem in a space that reduces to about N^11 or so when an SVD is applied .. and there are ways to "cheat" and do this faster on the fly.

[1] https://en.wikipedia.org/wiki/Gamma_spectroscopy

Last month I have ordered this pocket scintillator/spectroscope "Radiacode-101" from a Cyprus sales company.

https://radiascan.com/products/detector-of-ionising-radiatio...

The waiting time is few months, so I hope the toy arrives eventually.

Your guess about the airframes being booked has a ring of truth to it. I hadn't thought of that, and was wondering why radiometrics wasn't being used from the beginning.

The news was a bit of a beat-up and the chances of just accidentally stumbling on it out there were pretty remote to essentially nil. But what's authority to do? If some kid had found it and took it to school there'd be hell to play.

Based of its stated radiation signature it was always going to be easy to find. Right, it was a simple but nuisance task and took about as long as expected.

It was probably a mistake to report it to the public while it was still missing. That probably attracted a bunch of amateurs who could have ended up finding it. Far safer to look for it quietly first.

I guess that was because they were afraid of it getting stuck in a tire. If I found a strange metal cylinder in my tires, I would probably pick it up a try to find out what it is.

Did they close the road and/or put a checkpoint in place? That'd eliminate that risk.

The road you're talking about was 1400km long

1400km / (70km/h) = 20 hours of driving. This was no "a thousand volunteers on foot spent days searching for even a scrap of evidence" effort.

Pretty sure it's also the only road connecting a lot of these places; this is far remote WA.

I was considering going on a vacation/scavenger hunt when I saw the first article about it

> hell to play.

not sure if this was a typo, but the phrase I'm familiar with is "hell to pay".

https://dictionary.cambridge.org/us/dictionary/english/there...

Yeah, another damn typo I've missed, it's embarrassing. I understand the correct phrase.

Last week, I wrote 'we all cropped it' instead of 'we all copped it' which makes no sense—yet I reread that text three times, twice before posting and once thereafter and yet I still missed it.

I wish HN would allow typographical corrections past the usual edit deadline. Bad typos distract so they reduce the impact of what one is trying to say.

Thanks for pointing it out.

Depends if the wind blows it away.

It's steel around a ceramic slug mix doped with Cs-137 .. think about cutting 8mm off the end of a 6mm diameter steel bolt and dropping that to the ground.

It's going to take a good wind to blow that very far.

Especially once it drops a little bit below grade. Or gets covered with a bit of sand on the windward side. Unless picked up it was never going to be more than a few meters away from where it was lost.

I'd love to see some re-enactments and the spread of the spots where the pallet ended up after being lost on step one, that might give some indication as to whether it was found near its original landing point or further away from it.

Or a radioactive magpie.

they were initially concerned it would lodge in a knobby truck tire's treads and be carried off the known path, or so i read.

Also:

“... we’re a sophisticated nuclear nation and in many ways, we’re world leaders that punch above our weight when it comes to nuclear expertise and stewardship."

The stewardship claim bit seems maybe a bit overstated considering they weren't able to secure an object the size of a button leading to it "falling off the back of a truck"

My minds eye is seeing a crocodile Dundee type holding a beer in one hand and carefully balancing the capsule next to a sleeping kangaroo on a truck bed and securing it one handed with twine.

Your minds eye didn't see the koala riding shotgun?

"Call that a radiation source? Now that's a radiation source. " he said between bouts of violent vomiting.

> The stewardship claim bit seems maybe a bit overstated considering they weren't able to secure an object the size of a button leading to it "falling off the back of a truck"

As I understand it, this wasn't fuel, it was part of an instrument used by a mining company to measure the density of iron ore. The mining company (or a contractor depending on what you read) are the ones that lost it, the Australian government agency just came in to help find it.

And, it was secured inside an instrument inside a box strapped to a truck. The instrument had an unplanned disassembly in transit, and the cesium capsule fell through a hole in the bottom of the box, presumably used to bolt it down to its previous location. Failure to secure that hole (and any others in the box) was, in my opinion, the true failure of the mining company in this case.

Really I have no idea why this entire story has been made out to be such a big deal. Feels like deliberate distraction mass media usually does.

That still a massive search area for a very tiny object.

It's the distance between Austin TX and Los Angeles, CA. And they didn't know it was within 2m of the road- it might have bounced much further, or been hit by another vehicle and sent further. It might have been picked up by another vehicle, stuck in the tire perhaps.

Previous incidents like this have lead to deaths.

Let them celebrate.

>It might have been picked up by another vehicle, stuck in the tire perhaps.

Or used by Emus[1] to develop nuclear weapons.

[1] https://en.wikipedia.org/wiki/Emu_War

And it is vastly more radioactive than background. They might have used clever technology but someone in the passenger seat with a Geiger counter on their knee would probably have found it.

I agree. It seems that a simple gamma ray direction finder mounted to a low flying aircraft should have been sufficient assuming that the background radiation was not a concern. They could have triangulated/geolocated to a small area very quickly.

https://www.researchgate.net/publication/7009180_A_simple_ga...

Cool use of gamma-ray imaging technology! The underlying technology is a coded aperture to give a random response on the detector that can be used to reconstruct the direction of the gamma-ray source. I think they are using a moving mask with a single detector in the middle. They probably didn't know if the source had broken apart and caused more contamination when they found the general area. So the imaging allows you to know from a distance if the source has been distributed without going into a potentially loose contamination area.

Shameless plug: our company makes gamma-ray imaging systems and combines them with LiDAR mapping to make real-time 3D radiation maps: https://www.gammareality.com/ Basically we can make "nuclear street view" in real-time while driving around, or walking it around on Spot.

Cool tech! Spent a chunk of a past life building radiation detection equipment and mapping it in various ways - it's neat to see the state of the art moving forward. Is your LAMP device using coded aperture (in that tiny form factor?) or some other technique for mapping directionality?

Awesome! we're using coded aperture and Compton imaging

Here's a more technical/curiosity-satisfying answer to the question the title poses,

https://inis.iaea.org/collection/NCLCollectionStore/_Public/... ("Airborne Gamma Ray Spectrometer Surveying", 1991; 116p)

There's some really interesting case studies in chapter 9 ("Searching for Radioactive Objects"). The first one was more or less identical to the highway incident in Australia: "On 21 June 1968, a 325 mCi 60Co source was lost in transit somewhere between Salt Lake City, Utah, and Kansas City, Missouri, a distance of 1800 km." The other two were an American test ICBM that crashed in remote desert in Mexico, and a Soviet orbital nuclear reactor that crashed in Canada.

Back story: Rio Tinto apologises for losing radioactive capsule in Australia https://www.bbc.com/news/business-64448879

private company fucks up and government cleans up the mess :)

Still better than private company fucks up and hides their mess, continues polluting environment for decades.

The funds for this kind of search and similar emergency cleanups really need to be collected ahead of time (e.g. via taxes or required insurance) as making the company pay for it on the spot only encourages coverups.

In one of the articles yesterday, Rio Tinto said they'll pay the full cost of the recovery if the government sends them a bill.

What's the other option? Let the company search for it? You'd be complaining that the government wasn't involved enough if that's what they did.

The company offered to pay for the search before the search was even concluded. Not sure what more you can ask for.

fines and potentially losing their license for repeated mistakes

Wasn't this the opening scene to the Simpsons?

Do gamma rays bounce back on a rock or do you need line of sight to capture the source? If it is the latter they were very lucky, effectively one small stone away from never being able to find it.

Most rock is semi-transparent to gamma rays, which is how the lost source is intended to be used, to determine density of rock.

If the gamma rays are at 662 keV [1], you'd need about 8cm of rock [2] to block 50%. For comparison, sunglasses typically block 70%-80% of visible light.

[1] https://en.wikipedia.org/wiki/Caesium-137

[2] https://pdfs.semanticscholar.org/7248/4e8995c811d31837199d7c...

If something is easy to block, then it's probably not very dangerous.

So probably not the case.

When you think of things like Gamma or x-rays you cant relate them back to "light" because while there are similarities there are also a number of differences.

Gamma penetrates rocks, these sensors are used to help determine the density of rock by measuring how much was stopped by the material.

This is also why Gamma sources are so dangerous, because things like a coat, a car door are effectively "transparent" to them.

If there was just "one small stone" in front of the source it would almost be like it wasn't present at all.

I was hoping it was going to be by using antineutrinos, something the U.S. and the U.K. have been developing behind the scenes: https://www.sheffield.ac.uk/physics/research/particle/neutri...

In the US, the NNSA has helicopters with very sensitive radioactivity detectors. I live in DC and they‘ve flown straight rows over the city, back and forth, to create a background map of natural radiation. It’s not too surprising AU was able to find their missing capsule.

This is not the title of the article, and it should be changed.

Besides, what's kph?

km/h

The given title here is much more informative than the article title of "WA outback proves no match for Aussie nuclear know-how".

> Besides, what's kph?

Kilometres per hour.

> The given title here is much more informative than the article title of "WA outback proves no match for Aussie nuclear know-how".

It's in violation of HN guidelines.

American moment

Indeed. I use km/h

Not a imperial thing

The paranoid part of me has me thinking that all this sounds tailor made to showcase a product and a capability in a relatively safe setting. And you're really so hot on nuclear tech: don't lose your sources. That way you don't have to show off later on how good you are at finding them, aka the 'hero model' applied to nuclear physics.

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