The Momentum Distribution of Charged Cosmic Ray Particles Near Sea Level

Author: Glaser, Donald Arthur

Year: 1950

Degree: Dissertation (Ph.D.)

Advisor: Anderson, Carl D.

Committee Member: Unknown, Unknown

Option: Physics; Mathematics

DOI: 10.7907/QFA6-BT49

Abstract

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.

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