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Cloud-chamber observations of cosmic rays at high altitude


Cowan, Eugene Woodville (1948) Cloud-chamber observations of cosmic rays at high altitude. Dissertation (Ph.D.), California Institute of Technology.


Measurements of the distribution of zenith angles of large air showers made with a large cloud chamber at an altitude of 10,200 meters show the distribution to be much narrower about the vertical than that predicted by present shower theory. Although several experimental errors are present, the corrections are in such a direction as to augment the disagreement.

Evidence in the form of an elastic collision with an electron has been found for the existence in cosmic rays at high altitude of a low-mass mesotron. The mass as calculated from the angles of the elastic collision is approximately 13 times the mass of an electron. Since two such collisions occur on the same track, the probability of their being chance coincidences of nuclear deflections and knock-on electrons is small-- of the order of one in ten million.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Unknown, Unknown
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1948
Record Number:CaltechETD:etd-04082003-090035
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1299
Deposited By: Imported from ETD-db
Deposited On:08 Apr 2003
Last Modified:26 Dec 2012 02:36

Thesis Files

PDF (Cowan_ew_1948.pdf) - Final Version
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