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The Momentum Distribution of Charged Cosmic Ray Particles Near Sea Level


Glaser, Donald Arthur (1950) The Momentum Distribution of Charged Cosmic Ray Particles Near Sea Level. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/QFA6-BT49.


A new measurement of the momentum distribution of high energy charged cosmic ray particles at sea level has been made by means of a technique involving the use of two cloud chambers and a large electromagnet. With about twice the precision of previous determinations, the spectrum is extended to a momentum of pc = 80 Bev. For the 1547 measureable sets of tracks recorded, the positive-negative ratio is 1.26 ± 0.06, Up to the highest momenta measured the differential spectrum falls off as 1/ps with s = 2 very nearly. The positive excess and positive-negative ratio appear to be functions of momentum with the positives predominating at about 1.3 Bev. In other respects the positive and negative spectra are very similar.

Although the effect is barely outside statistical uncertainty, there seems to be an anomolous dip in the momentum distribution at about 3 Bev. In addition to this there seems to have been a small diurnal variation in the spectrum during the time the experiments were performed, 1 Bev and 4 Bev particles being slightly favored during the day and 3 Bev and 7 Bev particles being favored at night. These effects are discussed and the present results are compared with data of other experimenters.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Physics and Mathematics
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Minor Option:Mathematics
Awards:The Nobel Prize in Physics, 1960. Caltech Distinguished Alumni Award, 1966
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Anderson, Carl D.
Group:Nobel Prize, Caltech Distinguished Alumni Award
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1950
Additional Information:The Nobel Prize in Physics 1960 was awarded to Donald Arthur Glaser "for the invention of the bubble chamber."
Record Number:CaltechETD:etd-10112002-115844
Persistent URL:
Related URLs:
URLURL TypeDescription Prize announcement (Physics, 1960)
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4026
Deposited By: Imported from ETD-db
Deposited On:11 Oct 2002
Last Modified:27 Jul 2021 00:20

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PDF (Glaser_da_1950.pdf) - Final Version
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