Physicist Luis Alvarez proposed using muons, subatomic particles, to “X-ray” the pyramids of Giza, confirming the feasibility of muon tomography. Muon detectors have been used to study volcanos, Fukushima, and revealed hidden chambers in the pyramids. You can build a muon detector for $100 using Geiger-Müller tubes and an Arduino Nano. By using the coincidence method to filter out terrestrial particles, you can measure the flux of cosmic-ray muons accurately. With a homemade muon detector, you can explore underground structures like the Reed Gold Mine. Patience is needed to gather enough data for statistical precision, but it’s a unique way to harness the power of cosmic rays.
https://spectrum.ieee.org/diy-muon-tomography