from Hacker News

Muons used to test the condition of a road bridge in Estonia

by Fethbita on 3/16/25, 12:05 PM with 51 comments

• by csours on 3/19/25, 8:33 PM

  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]

• by megadata on 3/19/25, 11:36 PM

  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...

• by tagami on 3/19/25, 7:59 PM

  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/

• by rdtsc on 3/19/25, 8:15 PM

  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?

• by schoen on 3/19/25, 7:30 PM

  I did not know this was a thing!

  https://en.wikipedia.org/wiki/Muon_tomography

• by teamonkey on 3/20/25, 11:13 AM

  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.

• by IndrekR on 3/19/25, 8:23 PM

  Bit more info about the startup behind it: https://www.gscan.eu/

• by aigen000 on 3/19/25, 8:02 PM

  If I recall correctly, a similar method was used to discover a hidden passageway in the Egyptian pyramids.

• by dzhiurgis on 3/20/25, 1:32 AM

  Wonder if one could use muography to detect passing submarines

• by tomcam on 3/20/25, 4:39 PM

  > 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

• by aitchnyu on 3/20/25, 5:47 AM

  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.

• by dinkblam on 3/20/25, 4:15 AM

  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

• by krzysiek on 3/19/25, 9:00 PM

  They still do, but they used to too.