Alvarez's x-raying of the Gizeh pyramid


by DrDu
Tags: alvarez, gizeh, pyramid, xraying
DrDu
DrDu is offline
#1
Nov30-12, 02:36 PM
Sci Advisor
P: 3,375
I had a fascinating read about Alvarez "x-raying" the great pyramid in Gizeh in the 1960ies using cosmic muons:
www2.lns.mit.edu/fisherp/AlvarezPyramids.pdf
The technique has been refined and used even to make tomographies of a volcano in Japan.

What I wonder: To obtain the direction of the muons, one needs two ionization events. Isn't the probability for two ionizations in the spark chamber very low for muons which are so energetic that they can run unscattered trough the whole pyramid or a volcano?
Phys.Org News Partner Physics news on Phys.org
Physicists consider implications of recent revelations about the universe's first light
Vacuum ultraviolet lamp of the future created in Japan
Grasp of SQUIDs dynamics facilitates eavesdropping
mfb
mfb is offline
#2
Nov30-12, 02:42 PM
Mentor
P: 10,840
Isn't the probability for two ionizations in the spark chamber very low for muons which are so energetic that they can run unscattered trough the whole pyramid or a volcano?
They are not unscattered, but their scattering angle is very small over the whole length.
DrDu
DrDu is offline
#3
Nov30-12, 05:07 PM
Sci Advisor
P: 3,375
Ok, I just read that the muons have on the mean 4 GeV of energy when they reach the surface and that they loose about 2MeV per g cm-2. So they can travel about 20 m in e. g. water. On the other hand, this makes still about 1 keV loss per cm of air. Given that ionization requires some 10 eV, there should be about one ionization event every 0.1 cm.

mfb
mfb is offline
#4
Dec1-12, 01:13 PM
Mentor
P: 10,840

Alvarez's x-raying of the Gizeh pyramid


On the other hand, this makes still about 1 keV loss per cm of air. Given that ionization requires some 10 eV, there should be about one ionization event every 0.1 cm.
Every 10Ám?
For pyramids or mountains, you need the high-energetic muons.


Register to reply

Related Discussions
Baez Alvarez QG seminar notes Science & Math Textbook Listings 0
Pyramid in C++ Engineering, Comp Sci, & Technology Homework 14
square pyramid? General Math 4
Pyramid of Egypt Brain Teasers 12
Miguel C. Alvarez thesis posted today (Baez student) Beyond the Standard Model 4