Pyramid Scanning (~1970) • Luis Alvarez (1970): Are there undiscovered chambers in the Chephren pyramid? • Investigate with cosmic rays • Detector installed in chamber at the bottom (B) • Results compared to what would have been expected from a hidden chamber • Ultimately, hidden 1
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Pyramid Scanning (~1970) Luis Alvarez (1970): Are there undiscovered chambers in the Chephren pyramid? Investigate with cosmic rays Detector installed.
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Pyramid Scanning (~1970)
• Luis Alvarez (1970): Are there undiscovered chambers in the Chephren pyramid?
• Investigate with cosmic rays
• Detector installed in chamber at the bottom (B)
• Results compared to what would have been expected from a hidden chamber
• Ultimately, hidden chamber was ruled out
1
Volcano Radiography
• Internal structure of volcanoes not very well known
• Use cosmic rays to do radiographical scanning
2
Volcano Radiography
• Measure cosmic ray flux through volcano
• Obtain 2D density map
• Lots of data needed
• Then again, geologists have time…
Puy-de-dôme in Clermont-Ferrand, France(ToMuVol project)
3
Volcano Radiography
Mt. Iwatodake, Japan (Tanaka et al.)
4
National Security
• Safety of cargo an issue
• Nuclear material couldbe smuggled
• Many scanning methods(X-ray, neutrons, etc.)
• But generally expensive,and may introduce radiation
• Alternative: cosmic rays
5
Neutrinos
6(has been confirmed)
• Necessary to explain beta decay:
• Postulated 1930 by Wolfgang Pauli
• (Wasn’t too happy about it)
• Assumed to be massless, neutral cousin of the electron
• Almost no interaction with matter
• Still, discovered experimentally (1956 in a nuclear reactor, Cowan-Reines experiment)
Solar Neutrino Problem
7
• The sun is essentially a huge fusion reactor
• Produces large amounts of neutrinos
• Neutrinos can be measured as they arrive on earth
• Wrong amount of neutrinos found!
• Fewer neutrinos arrive than expected from solar models
Neutrino Oscillation
8
• Maybe solar models wrong?
• Turns out, nope.
• Problem resolved when neutrino oscillation was discovered
• Neutrinos switch back and forth between generations as they fly