Muons used to test the condition of a road bridge in Estonia
16 comments
·March 16, 2025csours
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]
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-...
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/
schoen
I did not know this was a thing!
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.
rdtsc
That's certainly a good reason. Thanks for explaining!
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...
krzysiek
They still do, but they used to too.
unit149
[dead]
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...