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How to find a tiny radioactive source while doing 70 kph

ansto.gov.au

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Re: How to find a tiny radioactive source while doing 70 kph

#11

Post by maven29 »

curiousgal wrote: post #7
gggggg5 wrote: post #4

Earlier quoted context omitted.

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?

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?

Re: How to find a tiny radioactive source while doing 70 kph

#12

Post by defrost »

throwbadubadu wrote: post #9
gggggg5 wrote: post #4

Earlier quoted context omitted.

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?

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.

Re: How to find a tiny radioactive source while doing 70 kph

#13

Post by hilbert42 »

gggggg5 wrote: post #4
dmurray wrote: post #3

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 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.

Re: How to find a tiny radioactive source while doing 70 kph

#15

Post by defrost »

SideburnsOfDoom wrote: post #10
defrost wrote: post #5

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 ag…

> 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…

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 , not much to see here.

Re: How to find a tiny radioactive source while doing 70 kph

#16

Post by perihelions »

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.

Re: How to find a tiny radioactive source while doing 70 kph

#17

Post by noja »

gggggg5 wrote: post #4
dmurray wrote: post #3

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?

Depends if the wind blows it away.

Re: How to find a tiny radioactive source while doing 70 kph

#19

Post by defrost »

noja wrote: post #17
gggggg5 wrote: post #4

Earlier quoted context omitted.

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?

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.

Re: How to find a tiny radioactive source while doing 70 kph

#20

Post by hilbert42 »

maven29 wrote: post #11
curiousgal wrote: post #7

Earlier quoted context omitted.

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.

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