Muons used to test the condition of a road bridge in Estonia
53 comments
·March 16, 2025csours
kulahan
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-...
null
lazide
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!
Cthulhu_
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.
megadata
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...
perihelions
Also on HN,
https://news.ycombinator.com/item?id=43195525 ("A $100 DIY muon tomographer (ieee.org)", 20 days ago, 45 comments)
tagami
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/
rdtsc
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?
thinkingQueen
> 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.
jldugger
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.
mschuster91
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
theultdev
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.
rdtsc
That's certainly a good reason. Thanks for explaining!
chrisweekly
Here I was thinking it had something to do with trolls...
Sorry, couldn't resist. Agreed, it's a helpful explanation.
barrenko
It's a three days ride (at a leisure pace of like 40 km/h) from Crimea to Bruxelles.
schoen
I did not know this was a thing!
teamonkey
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.
agnishom
How do you know it's related to a muon?
kimixa
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...
teamonkey
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.
Sharlin
Not a lot of local radiation can make it to a sensor inside a camera inside a fridge, though.
IndrekR
Bit more info about the startup behind it: https://www.gscan.eu/
aigen000
If I recall correctly, a similar method was used to discover a hidden passageway in the Egyptian pyramids.
dpedu
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.
throw-qqqqq
You do recall correctly!
https://www.nationalgeographic.com/science/article/giza-pyra...
dzhiurgis
Wonder if one could use muography to detect passing submarines
webdoodle
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...
RickyS
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.
cameldrv
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.
TheSpiceIsLife
Fission reactors spew neutrinos, no need for anti-
Timwi
Antineutrinos are produced in nuclear reactors when the radioactive products of nuclear fission undergo beta decay.
tomcam
> 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
aitchnyu
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.
dinkblam
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
hugh-avherald
Can we have one topic on hackernews that doesn't mention rust?
TheSpiceIsLife
Carefully and purposefully Oxidising Bridges with Rust.
shepmaster
That is a use of https://en.wikipedia.org/wiki/Weathering_steel, actually!
https://en.wikipedia.org/wiki/Luis_Walter_Alvarez
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]