Variation of Helium Intensities with Current Density and Pressure

Citation

Michels, Walter Christian (1930) Variation of Helium Intensities with Current Density and Pressure. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/0vzg-ec30. https://resolver.caltech.edu/CaltechTHESIS:08272024-152129351

Abstract

A review of the literature on the subject of the excitation function of helium shows wide discreptancies in the experimental results. The author has attempted to trace the sources of these differences and has found that there are two aspects in which the experimental conditions differ from ideal. These are:

1. A failure in the production of a homogenous electron beam.

2. Deviations of the excitation conditions from simple excitation.

The first of these difficulties has been overcome, to a very large extent, by the use of a specially designed discharge tube. The development of this tube, together with the improvements in the homogeneity of the electron beam, is traced.

In respect to the second point, it is shown that the criterion for simple excitation is a linear dependence of intensity on current or pressure. This has not been obtained, in general, by previous workers. With the apparatus mentioned above this linear relationship is obtained only by proper cleaning of the tube. The final results show linearity within the experimental error.

The intensities have been measured by a new modification of the Ornstein-Dorgelo method.

Thesis Files