Muons used to test the condition of a road bridge in Estonia(news.err.ee)
news.err.ee
Muons used to test the condition of a road bridge in Estonia
https://news.err.ee/1609634600/muons-used-to-test-the-condition-of-a-road-bridge-in-estonia
53 comments
They were indeed able to do this after all [1], and found some unknown voids.
[1] https://spectrum.ieee.org/muon-imaging-finds-hidden-chamber-...
[1] https://spectrum.ieee.org/muon-imaging-finds-hidden-chamber-...
[deleted]
At least one was confirmed to indeed be exist - quite fascinating.
One day hopefully we can find out if the remaining giant looking open area exists too!
One day hopefully we can find out if the remaining giant looking open area exists too!
Wouldn't there be other ways to detect voids? Strong X-Rays, penetrating radar, or sound wave / seismic measurements taken from every outside and accessible inside space, combined into a 3d model / visualisation. Or is the stone used that impenetrable? I have no idea about these things.
Those other methods do get used, but are of limited utility because the stone is that impenetrable - and it’s a masonry structure with a significant amount of joints, random small voids, etc.
It really does benefit from something like muon/neutron radiation, where absorption is quite low/penetration quite high, so we can ‘see’ pass the first couple centimeters to meters.
It really does benefit from something like muon/neutron radiation, where absorption is quite low/penetration quite high, so we can ‘see’ pass the first couple centimeters to meters.
Muons were also recently on hackaday. DIY ground penetrating radar ...
Building A DIY Muon Tomography Device For About $100
https://hackaday.com/2025/02/26/building-a-diy-muon-tomograp...
Building A DIY Muon Tomography Device For About $100
https://hackaday.com/2025/02/26/building-a-diy-muon-tomograp...
Also on HN,
https://news.ycombinator.com/item?id=43195525 ("A $100 DIY muon tomographer (ieee.org)", 20 days ago, 45 comments)
https://news.ycombinator.com/item?id=43195525 ("A $100 DIY muon tomographer (ieee.org)", 20 days ago, 45 comments)
Here is an example used in the mining industry. I heard them present at a NASA/USGS conference last month regarding in situ resource ultilization: https://ideon.ai/
Neutrons can be used for these things as well. The advantage, say from x-rays, is attenuation is not by material density, where all metals will just look dark, but by thermal neutron absorption cross section. So boron might be dark, but metals won't be.
Muons are much nicer as you don't have to carry a neutron source around with you.
> However, if anyone is now thinking of standing under the bridge to get their body scanned, they shouldn't bother. First, they'd have to stand still for an hour, and second, the security patrol would be there within minutes.
Security patrol will come and bother you if you hand around the bridge for a few minutes?
Muons are much nicer as you don't have to carry a neutron source around with you.
> However, if anyone is now thinking of standing under the bridge to get their body scanned, they shouldn't bother. First, they'd have to stand still for an hour, and second, the security patrol would be there within minutes.
Security patrol will come and bother you if you hand around the bridge for a few minutes?
> Security patrol will come and bother you if you hand around the bridge for a few minutes?
There’s a land war in Europe. Hundreds of thousands have lost their lives during the past few years. There have been cases of sabotage against the Baltic states as well as the Nordic states. Things are pretty grim there and lurking around basic infrastructure pretty much guarantees a talk with the police.
There’s a land war in Europe. Hundreds of thousands have lost their lives during the past few years. There have been cases of sabotage against the Baltic states as well as the Nordic states. Things are pretty grim there and lurking around basic infrastructure pretty much guarantees a talk with the police.
And it's not just Europe either. The US has suffered from multiple attacks on electrical substations [1] as well with unknown perpetrators (the suspicion is white supremacists), and on top of that come rednecks shooting at power lines and god knows what else.
Paranoia surrounding critical infrastructure is skyrocketing at the moment, and I'd say for a bunch of very good reasons.
[1] https://en.wikipedia.org/wiki/Moore_County_substation_attack
Paranoia surrounding critical infrastructure is skyrocketing at the moment, and I'd say for a bunch of very good reasons.
[1] https://en.wikipedia.org/wiki/Moore_County_substation_attack
the "rednecks" are the ones fixing power lines for you.
your neck may not be red because you get to sit inside while they keep your power on for you.
meanwhile you sit inside writing your hateful, elitist, garbage.
the conspiracy theories related to event you linked are ridiculous.
your neck may not be red because you get to sit inside while they keep your power on for you.
meanwhile you sit inside writing your hateful, elitist, garbage.
the conspiracy theories related to event you linked are ridiculous.
> your neck may not be red because you get to sit inside while they keep your power on for you.
Before I got into IT I was working in construction for our local telco provider, believe me I have seen shit.
Before I got into IT I was working in construction for our local telco provider, believe me I have seen shit.
Plus Estonia in particular is 200km away from St Petersberg, and 800km from Moscow. They are all but guaranteed to succumb to Russian expansion if allowed to continue unchecked.
That's certainly a good reason. Thanks for explaining!
Here I was thinking it had something to do with trolls...
Sorry, couldn't resist. Agreed, it's a helpful explanation.
Sorry, couldn't resist. Agreed, it's a helpful explanation.
It's a three days ride (at a leisure pace of like 40 km/h) from Crimea to Bruxelles.
I did not know this was a thing!
https://en.wikipedia.org/wiki/Muon_tomography
https://en.wikipedia.org/wiki/Muon_tomography
Muons can be picked up by a standard DSLR. Put the cap on (remove the lens if possible), set it to continually take long exposures of 30s or more, put it in a sealed plastic box with some silica gel packets and put the whole thing in the fridge for a while.
Most of the frames will just show noise from the sensor and electronics (the low temperature minimises that), but occasionally you'll see a bright streak as a muon hits it.
Most of the frames will just show noise from the sensor and electronics (the low temperature minimises that), but occasionally you'll see a bright streak as a muon hits it.
How do you know it's related to a muon?
I'd think it's pretty much any high-energy ionizing radiation that causes those streaks - probably very few of which are muons. There are "local" sources of ionizing radiation pretty much everywhere.
And if [0] is correct about the approximate muon flux - being that "about one per second passes through a volume the size of a person’s head.", the volume of a the CCD sensor that it would have to interact with is so much smaller (being some 10 microns thick) that I doubt it'll be "Take a few 30s exposures" sort of chance, so much as "Winning the lottery" level chance to actually have a muon pass through the sensor, and interact.
[0] https://home.cern/science/physics/cosmic-rays-particles-oute...
And if [0] is correct about the approximate muon flux - being that "about one per second passes through a volume the size of a person’s head.", the volume of a the CCD sensor that it would have to interact with is so much smaller (being some 10 microns thick) that I doubt it'll be "Take a few 30s exposures" sort of chance, so much as "Winning the lottery" level chance to actually have a muon pass through the sensor, and interact.
[0] https://home.cern/science/physics/cosmic-rays-particles-oute...
It doesn't have to hit the sensor, it needs to pass through it, so the thinness of it doesn't matter as much as the orientation; it's a matter of flux density.
You would expect ap to 2-3 muons per minute to pass through a typical sensor but you might not capture all of them.
You would expect ap to 2-3 muons per minute to pass through a typical sensor but you might not capture all of them.
It has to interact, otherwise it wouldn't be visible at all, as it's the interactions that the CCD detects.
And as muons don't interact often, the can pass through a lot of matter without anything noticing - that's the reason why they can pass through the atmosphere to still be detected on the ground - or even deep underground, as many imaging detectors are used, to avoid other radiation sources that could cause noise while still penetrating the rock you want to image. Compared to hundreds of metres of rock in a deep mine, a fridge and roof is nothing.
And as muons don't interact often, the can pass through a lot of matter without anything noticing - that's the reason why they can pass through the atmosphere to still be detected on the ground - or even deep underground, as many imaging detectors are used, to avoid other radiation sources that could cause noise while still penetrating the rock you want to image. Compared to hundreds of metres of rock in a deep mine, a fridge and roof is nothing.
The muon’s charge excites electrons as it passes through an atom’s electromagnetic field. The camera is detecting this trail of ionisation as the muon passes between the atoms of the sensor (and these sensors are very good at detecting excited electrons). The muon does NOT need to decay or to strike the atoms of the sensor directly in order to be detected.
In open air at sea level, you would expect 1 muon to pass through any square cm of ground every minute, on average. With a sensor measuring 2-3 sq cm, oriented correctly, and exposing for a long enough time you would certainly expect to catch a few.
Unlike x-rays or gamma radiation, muons can pass through several km of dense matter and penetrate deep inside the earth before they decay. They can pass through solid lead. Direct particle collisions are rare but more likely when passing through large amounts of dense matter. The ionisation process can also reduce the speed and trajectory. Muon tomography works by comparing how much the muon count has been reduced compared to an expected background level.
The practice of capturing muons on camera is quite well established, see for example https://pmc.ncbi.nlm.nih.gov/articles/PMC10220736/
In open air at sea level, you would expect 1 muon to pass through any square cm of ground every minute, on average. With a sensor measuring 2-3 sq cm, oriented correctly, and exposing for a long enough time you would certainly expect to catch a few.
Unlike x-rays or gamma radiation, muons can pass through several km of dense matter and penetrate deep inside the earth before they decay. They can pass through solid lead. Direct particle collisions are rare but more likely when passing through large amounts of dense matter. The ionisation process can also reduce the speed and trajectory. Muon tomography works by comparing how much the muon count has been reduced compared to an expected background level.
The practice of capturing muons on camera is quite well established, see for example https://pmc.ncbi.nlm.nih.gov/articles/PMC10220736/
Not a lot of local radiation can make it to a sensor inside a camera inside a fridge, though.
Radioactive isotopes are everywhere, in the air, in the plastic box you put the camera in, in the camera frame itself.
I guess that by far the most likely local source would be potassium-40 which is a gamma emitter and relatively abundant in organic stuff. Due to the low penetration of alpha and beta radiation, the source would have to be inside the camera to even have a chance of hitting the sensor, limiting the rate of such events.
[0] seems to imply the vast majority of radiation the average person experiences is gases, like Radon and Thoron decay (itself just an isotope of Radon), which would likely be as prevalent inside the fridge (and so inside the camera frame itself) as anywhere else.
[0] https://www.epa.gov/radiation/radiation-sources-and-doses
[0] https://www.epa.gov/radiation/radiation-sources-and-doses
That's because there's gaseous radon-222 continuously released from soil and rock, as a decay product of natural uranium. But it's an alpha emitter so is stopped by anything, including a few cm of air, or a sheet of paper – or the glass filter in front of a digital camera sensor.
But the lens and camera assembly isn't a vacuum, if there's radon in the air around the camera I'd expect radon to be inside the camera too, right by the CCD.
Yes, but that amount of air is going to contain a rather insignificant amount of radon atoms. And as I said, even alpha particles emitted inside the camera have little hope of actually making it to the sensor, which is sandwiched between several layers of filters and the backside electronics and the camera chassis. (4He nuclei from space, making up around 10% of cosmic rays, on the other hand can have enough energy to penetrate the atmosphere and up to tens of meters of solid matter, so you might certainly capture some of those, besides the muons.)
Bit more info about the startup behind it: https://www.gscan.eu/
If I recall correctly, a similar method was used to discover a hidden passageway in the Egyptian pyramids.
You do recall correctly!
https://www.nationalgeographic.com/science/article/giza-pyra...
https://www.nationalgeographic.com/science/article/giza-pyra...
Two voids were discovered - and the one you mentioned has since been breached and a camera inserted. I'm avoiding the word passageway because the general interpretation is that it seems to be an inspection space or stress relief chamber, as it sits directly above the "actual" entrance to the pyramid.
Video on the subject: https://www.youtube.com/watch?v=49870qW9pQ8
The second void is more exciting, in my option. It is much larger - it is thought to be of similar size of the Grand Gallery, and sits some distance above it.
Video on the subject: https://www.youtube.com/watch?v=49870qW9pQ8
The second void is more exciting, in my option. It is much larger - it is thought to be of similar size of the Grand Gallery, and sits some distance above it.
Wonder if one could use muography to detect passing submarines
Yes. Nato is has been testing the Watchment muon detection system that was designed to track nuclear material, specifically looking for nuclear submarines.
https://thedebrief.org/darpas-secretive-new-neutrino-detecto...
https://thedebrief.org/darpas-secretive-new-neutrino-detecto...
Another one along these lines is antineutrinos. They're created by fission reactions, so a nuclear reactor puts out a lot of them. From what's available in the open literature, this seems like it might be getting close to being practical.
Fission reactors spew neutrinos, no need for anti-
Antineutrinos are produced in nuclear reactors when the radioactive products of nuclear fission undergo beta decay.
Source: https://physics.aps.org/articles/v10/66
Source: https://physics.aps.org/articles/v10/66
Ah, right.
This publication[1] says neutrinos, but the article it references says antineutrinos[2].
That explains my misunderstanding.
1 https://www.energy.gov/science/np/articles/detecting-neutrin...
2. https://www.osti.gov/pages/biblio/1959810-evidence-antineutr...
This publication[1] says neutrinos, but the article it references says antineutrinos[2].
That explains my misunderstanding.
1 https://www.energy.gov/science/np/articles/detecting-neutrin...
2. https://www.osti.gov/pages/biblio/1959810-evidence-antineutr...
It's a bit challenging as the submarine would need to stand still for a while and not be very deep but some people has thought about that.
> This week, a new technology was tested in Jõgisoo, Harju County, as part of a nearly €1.3 million research project.
I’m already using the €235,999 Harbor Freight version for my bridge tests
I’m already using the €235,999 Harbor Freight version for my bridge tests
Is there a diagram of this? I'm imagining a plate that "see" at a 180 degree field of vision when cosmic rays hit it from every angle from the sky there are opaque things between the sky and sensor.
on that topic, rust costs us 3.4 trillion per year [1] and the (public) construction industry has not even started to address the issue
[1] http://impact.nace.org/economic-impact.aspx
[1] http://impact.nace.org/economic-impact.aspx
Can we have one topic on hackernews that doesn't mention rust?
Carefully and purposefully Oxidising Bridges with Rust.
That is a use of https://en.wikipedia.org/wiki/Weathering_steel, actually!
Yes! Commonly known in Australia by the brand name Corten (COR-TEN)[1].
1. https://en.m.wikipedia.org/wiki/Weathering_steel
I laser cut and help press about half the cladding at MONA near Hobart, a gallery owned by professional gambler David Walsh.
If you haven’t been, go!
It’s an underground art gallery, complete with wind tunnel reminiscent of a vacuum cleaner tube, and a permanent installation of a digesting shit machine, amongst other subservience adult Disneyland weirdness.
https://mona.net.au/visit
https://www.discovertasmania.com.au/things-to-do/museums/mon...
https://en.m.wikipedia.org/wiki/Museum_of_Old_and_New_Art
https://en.m.wikipedia.org/wiki/David_Walsh_(art_collector)
1. https://en.m.wikipedia.org/wiki/Weathering_steel
I laser cut and help press about half the cladding at MONA near Hobart, a gallery owned by professional gambler David Walsh.
If you haven’t been, go!
It’s an underground art gallery, complete with wind tunnel reminiscent of a vacuum cleaner tube, and a permanent installation of a digesting shit machine, amongst other subservience adult Disneyland weirdness.
https://mona.net.au/visit
https://www.discovertasmania.com.au/things-to-do/museums/mon...
https://en.m.wikipedia.org/wiki/Museum_of_Old_and_New_Art
https://en.m.wikipedia.org/wiki/David_Walsh_(art_collector)
They still do, but they used to too.
Alvarez proposed muon tomography in 1965 to search the Egyptian pyramids for unknown chambers. Using naturally occurring cosmic rays, his plan was to place spark chambers, standard equipment in the high-energy particle physics of this time, beneath the Pyramid of Khafre in a known chamber. By measuring the counting rate of the cosmic rays in different directions the detector would reveal the existence of any void in the overlaying rock structure.[48]