12 ms·
Radiation detection is my specialty. This source is Cs-137, few hundred mCi. It's easy to detect within a few seconds at distances of a few tens of meters or mo
by BetterGeiger 4y ago
Radiation detection is my specialty. This source is Cs-137, few hundred mCi. It's easy to detect within a few seconds at distances of a few tens of meters or more with professional detection equipment if there is direct line of sight.
If it was knocked off the road, though, the question will be if it fell into a crack or other such place because then the radiation is somewhat shielded and it would take much more measuring time to identify it.
I suspect if a few passes with vehicle-mounted detectors don't find it then some drones with detectors traveling along the sides of the road would be a good next step. If a critter moved it or ate it then it's probably gone forever. At a distance of 1 meter the dose rate from that source is already not extremely hazardous unless a person were exposed for an extended period of time (like a full day or two). Getting closer, like putting it directly against your torso, would mean serious health effects in a matter of minutes.
- pxmpxm 4y ago[flagged]
- sn9 4y agoThis is an interesting algorithm problem. Given the parameters to maximize detection and minimize time/resources, how would you direct a drone or something to find the capsule? How would that change with 2 drones? 4? 8? As many drones as there are flyable Geiger counters in the country?
- cdjk 4y agoIt’s called Bayesian Search Theory, and is even more interesting when you consider that not finding it at a given location gives you information about where it might or might not be.
- Scoundreller 4y agoI wonder if analog dosimeters might be a better way to narrow down the search area more cheaply and quicker to set-up. Fly or drive a run. Check dosimeter. Dunno if there's enough energy expected to set it off at the expected speeds travelled. Obviously they don't go "ding ding ding". Might find some spurious beta-radiation sources? https://www.uth.edu/safety/radiation-safety/personal-radiation-dosimeter.htm https://www.uth.edu/safety/radiation-safety/personal-radiati...
- Piskvorrr 4y agoIt comes down to SNR, like most searches...and it's not very high in this case.
- defrost 4y agoYou'd pretty much start with a local radiometric survey company (there are a few in Perth) using a 50 litre doped sodium iodide cyrstal pack (a bit heavy for a drone) and scintillation counters in a crop duster flying at 40 m ground clearence dead centre down the road at 70 m/sec for the full 1,400 km road length. Post process the 256 value gamma spectrum, correcting for cosmic, aircraft signature, remove the mean average W.Australia backround signature, run a full rolling NASVD to peak sharpen and look for 32 and 662 kev twin peaks. Then you'd start with the local area ground search. Given the lapsed time already there's a good chance the slug in question was either magpie'd on site or has been picked up in a tire and gone off route.
- sockaddr 4y agoI was going to say that too.
- POPOSYS 4y agoWhat literature would you recommend to better understand these procedures?
- defrost 4y agoIf you're interested: Guidelines for radioelement mapping using gamma ray spectrometry data International Atomic Energy Agency (2003) https://www-pub.iaea.org/mtcd/publications/pdf/te_1363_web.pdf https://www-pub.iaea.org/mtcd/publications/pdf/te_1363_web.p... Or go full Aussie, Aussie, Oy, Oy, Oy https://www.ga.gov.au/scientific-topics/disciplines/geophysics/radiometrics https://www.ga.gov.au/scientific-topics/disciplines/geophysi... and read the three publications linked at bottom and get the high res A0 wall map for the dorm room ! ( A GUIDE TO THE TECHNICAL SPECIFICATIONS FOR AIRBORNE GAMMA-RAY SURVEYS Grasty + Minty https://d28rz98at9flks.cloudfront.net/14861/Rec1995_060.pdf https://d28rz98at9flks.cloudfront.net/14861/Rec1995_060.pdf and the other two )
- POPOSYS 4y agoTHANKS!
- KingMob 4y agoFirst you chop up the road, and sort by radioactivity...
- animal531 4y agoWhat if we recreate the journey, use the same truck with the same type of containers and see if we can re-create the malfunction, then start the search forward/backwards from there?
- BetterGeiger 4y agoHere's how I would approach it... Based on a given detector geometry you can imagine it has a detection efficiency as a function of distance from the detector. Now you can imagine the source traveling in a straight line such that it passes some minimum some distance from the detector and at some velocity. From that path there is an expected number of counts that the detector would receive on average from that source as a function of minimum distance. Using that function and the background count rate one can estimate how close the source path needs to be from the detector to reliably detect it. From this you can optimize the altitude and velocity of the detector traveling along the road. I hope this brief explanation makes some sense. The hardest part would be to decide what signal to noise ratio is acceptable. For vehicle mounted it would simpler because you can probably just fix the elevation and only focus on the velocity as a variable.
- nosmokewhereiam 4y agoAny recommendations for detection at home? Are wearable dosimeters enough to detect before damage occurs? ...or if there is already a crowdsourced detection effort for looking out for this sort of thing, that'd be a cool map to plot.
- 13of40 4y agoYou can get a detector/dosimeter on Amazon in the $50ish range. I got one a while back and verified it works for increased background radiation at 30,000 feet in a plane and separately with an alpha radiation source. The interesting thing is if you leave it on the background radiation sometimes just spikes for no apparent reason. Maybe something like a cosmic ray hitting the sensor every once in a while? The one I got is on Amazon as "Geiger Counter Nuclear Radiation Detector, Professional High Accuracy Radioactive Detector Meter Beta Gamma X Ray Data Tester Marble Dosimeter".
- BetterGeiger 4y agoYes, I recommend mine ;) ... the "Better Geiger S-1" In the budget price range (~$150 and under) my detector, which uses a solid scintillator, and a traditional Geiger tube based device are really the only options worth considering. The pros of my detector are high range (max 20 mSv/hr vs typically 1 mSv/hr for common Geiger tubes), roughly 3x higher X-ray/gamma sensitivity, and automatic energy-correction of dose rate for better accuracy in realistic scenarios. I also think the design is pretty robust and user-friendly, people seem to like it. A traditional Geiger tube has some pros also. The only ones worth getting in the budget range, in my opinion, are the GQ GMC type (there are variants but most are basically the same). They are a little cheaper and they have more bells and whistles like data logging. Another pro is that they have higher beta sensitivity, but that's a con also. Antiques like uranium glass and fiestaware are primarily low energy beta emitters so my detector reacts very weakly but a Geiger tube reacts very strongly. That's a con also, though, because when measuring dose you should NOT measure beta, so it means traditional Geiger tubes dramatically overestimate dose rate when they are exposed to beta (a common mistake among beginners). Just please don't buy any of the super cheap import detectors that have suddenly appeared on the market in the last year or so, they are all terrible. At higher prices (~$400 and up) there are a lot of different options with pros and cons, it just depends what the intended applications of the detector are.
- Bluecobra 4y ago> Getting closer, like putting it directly against your torso, would mean serious health effects in a matter of minutes. Let’s hope that some random person doesn’t find it and turn it into a necklace or something. The TNG episode “Thine Own Self” comes to mind.
- rowanG077 4y agohttps://en.wikipedia.org/wiki/Goi%C3%A2nia_accident https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident Stuff of nightmares.
- twawaaay 4y agoOr in a wall of a building: https://en.wikipedia.org/wiki/Kramatorsk_radiological_accident https://en.wikipedia.org/wiki/Kramatorsk_radiological_accide...
- qikInNdOutReply 4y agoThats a horror story, but the actual horror is society picking not up on this until its too late for alot of lifes. This is one of the incidents, that a centralized health system with data mining could have picked up easily.
- h0l0cube 4y agoBoth of those stories are from the 80s, when hard drives were the size of washing machines and an internet connection was an unlikely thing to have outside the military and larger scientific institutions (e.g., CERN).
- floxy 4y agoThe original IBM PC/XT had a 10 MB internal 5-1/4" hard drive in 1983. https://en.wikipedia.org/wiki/IBM_Personal_Computer_XT https://en.wikipedia.org/wiki/IBM_Personal_Computer_XT
- Aeolun 4y agoI was thinking, 10 x-rays per hour doesn’t sound so terrible. But if you bring it closer than 1 meter it would start getting exponentially worse.
- cocomutator 4y agoNot exponentially, just inverse-quadratically :)
- amluto 4y agoPresumably something that got exponentially worse with proximity would have badness e^(-kr) where r is distance and k is some constant. So depending on k, it’s worse by some constant amount when you bring d down from 1 meter to zero. This is, notably, finitely worse. But k/r^2 (different k) is a whole different beast. It’s infinitely worse at zero distance! Of course, the radioactive source itself is not a point, and the human body isn’t a point either, so it’s not infinitely bad at zero range. Closer than a meter or so (very roughly the size of a body), it will merely concentrate the exposure over a smaller portion of the target and deliver a larger fraction of its total output to the target. The latter effect is a constant factor not vastly greater than 1 when comparing 1 meter to zero meters.
- wkat4242 4y ago> I was thinking, 10 x-rays per hour doesn’t sound so terrible. I believe the popular term is "not great, not terrible" ;)
- bamboozled 4y agoIf a critter moved it or ate it then it's probably gone forever. At a distance of 1 meter the dose rate from that source is already not extremely hazardous unless a person were exposed for an extended period of time (like a full day or two). Getting closer, like putting it directly against your torso, would mean serious health effects in a matter of minutes. Bit of contradiction in your statement here? If putting it against your torso would mean serious health effects in minutes, how would a critter "eat" it and get more than a few meters away? I guess by minutes you mean tens of minutes?
- Always42 4y agoPlaying devils advocate, what if a bird grabs it and fly's 1000 meters before death?
- elromulous 4y agoNot op, or an expert on radiation poisoning, but, one can receive a lethal dose of radiation in an instant (and be condemned to certain death) but not die for weeks. Credentials: I've read about the demon core[0] and watched Chernobyl on HBO. [0] https://en.wikipedia.org/wiki/Demon_core https://en.wikipedia.org/wiki/Demon_core
- elromulous 4y agoP.s. Also see this https://en.wikipedia.org/wiki/Therac-25 https://en.wikipedia.org/wiki/Therac-25
- suprjami 4y agoPlease consider writing to the responsible government department and give them your credentials and suggestion. This thing has been missing for months. Their current detection strategy is to post a picture of a watch battery on Facebook and hope it just magically shows up. We're a little deficient in technology here in Australia, especially in government, doubly so in state government.
- onlyrealcuzzo 4y agoIf they at least listen to reason, it doesn't seem like you can't ask for much more.
- Jedd 4y ago> This thing has been missing for months. Where are you getting months from? " ... the truck made the journey from 12th to 16th of January, the capsule was not discovered to be missing until the 25th of January." It's been missing for 2 weeks, and known to be missing for 5 days.
- defrost 4y ago> This thing has been missing for months. It was lost in transit at most 20 days ago between January 11 and January 16. It was logged as missing five days ago on January 25. > Their current detection strategy is to post a picture of a watch battery on Facebook and hope it just magically shows up. This is patently false. > We're a little deficient in technology here in Australia Perhaps surprisingly Australia is one of the world leaders in international radiometric mapping having expertise going back 50+ years having mapped multiple entire countries (Australia, Fiji, Mali, and a number of others). See (for example): https://www.publish.csiro.au/EG/EG09025 https://www.publish.csiro.au/EG/EG09025 (2009) Perth is home to several radiometric mapping companies and capable airframes.
- atlastreasure23 4y agoI’m usually one of the first to throw shade at the Australian government but to claim that “this thing has been missing for months” isn’t misleading - it’s a lie. https://en.m.wikipedia.org/wiki/Western_Australian_radioactive_capsule_incident#Timeline https://en.m.wikipedia.org/wiki/Western_Australian_radioacti... Also to say the tactics being used to find the capsule being limited to “post a picture of a watch batter on Facebook and hope it magically shows up” would be misleading. 1)The public alerts and posts are to keep the public informed as to what it is. This is for the very small chance someone does stumble onto it to limit the risk to the public. 2)They are searching the route with handheld detectors and soon detectors on vehicles using the trucks GPS data to map the route https://www.theguardian.com/australia-news/2023/jan/29/new-technology-deployed-in-search-for-tiny-potentially-deadly-missing-radioactive-capsule https://www.theguardian.com/australia-news/2023/jan/29/new-t...
- techdragon 4y agoThe biggest problem is going to be if it got embedded in a tire. The hope is that it’s “just on the side of the road”. But there’s a very real possibility that this could get picked up by someone’s car, wedged into the tire tread, and sit in their garage slowly exposing them and/or their family if the garage is used for anything else. Or any other car related exposure scenarios such as part time rideshare driver or work vehicles. And it could spend some time Slowly getting its surface chipped and abraded by regular driving wear, spreading out the risk… which could be good or bad depending on how large the pieces are.
- N19PEDL2 4y agoThe Australian Government should urge all those who travelled that road after the item was lost to inspect the tyres of their car and possibly the garage.
- BetterGeiger 4y agoI think they have already done that. I doubt a large percentage of people will both see the request and follow through with it.
- triggercut 4y agoThat's good to know, some useful context: tldr: It's going to take a while The search area is immense. People (even locals) fail to understand the incredibly vast distances. Sure, you can think up a comparison from your own context of a few hundred kms... but does your example have nothing, and I mean, literally nothing manmade but the road infrastructure itself in the proximity of the horizon for sometimes hundreds of kms? Few places do. In more remote places than this, say in the Kimberly, you might as well be on the moon. There's nothing out there to support you or resupply you; you always have to think about that ahead of time. It's the middle of summer here, we are approaching our hottest month (February). Pavement, being a heat island, makes working alongside or on it a slow process. Exposure and heat stroke are real risks. On the upside, the roads are sealed, and in relatively good condition and well designed when compared to say much of the US or the poorer parts of Europe but the odds that it falls into a crack or pothole will scale with the distance. A vehicle-mounted detector makes obvious sense but could be costly. However, as we know, especially at these temperatures, roads are slow moving rivers. It might even become embedded if it did indeed land on the surface. In which case it sounds like we may never find it. Assuming it's most likely in the literal middle of nowhere. The risk of a member of the public coming into to direct physical contact would be highly unlikely. There are sections of road that haven't had human feet walk on them since they were last poured. But that introduces an interesting problem. What happens next time maintenance replace that section? Do crews need to be wary of digging it up, possibly aresolising it in the process? Maintenance is probably the most likely human contact scenario. Does every safety management plan now include the incredibly remote chance of finding it?
- ferrumfist 4y ago> US or the poorer parts of Europe Sorry to nitpick, but I've driven across the USA many times and I've never had much to complain about with regards to our roads (outside of Ohio, fuck that state). Doubly so when comparing our road infrastructure to poorer countries.
- plugin-baby 4y agoAround San Francisco they’re noticeably worse than the well maintained parts of Europe.
- arbitrandomuser 4y agoHow long till it decays to reasonable safe levels ?
- tlonny 4y agoI read that the half life is 30 years - so a good amount of time unfortunately...