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The absorption coefficient for slow electrons in gases

Brode, Robert B. (1925) The absorption coefficient for slow electrons in gases. Physical Review, 25 (5). pp. 636-644. ISSN 0031-899X.

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Electrons from a heated filament were accelerated through a slit and deflected magnetically around a circular path into a Faraday cylinder connected to a galvanometer. From the plots of the logarithm of the ratio of the galvanometer current G to the total electron current M from the filament, as a function of the pressure, the absorption coefficients were determined for various accelerating voltages from 2 to 360. For a given voltage, the absorption coefficient was found to be independent of the current M and also of the pressure (at about 10^-2 mm). The results of Mayer and Ramsauer were checked for argon and helium. In argon, the coefficient reaches a sharp maximum at about 12 volts, the value for 2 volts being only one-fifth of the maximum value. In helium there is a maximum at 4 volts. Methane gave a curve similar to these, with a maximum at about 7.5 volts, which is in agreement with the results of Akesson. The curves for nitrogen and carbon monoxide are nearly identical, both having a maximum at about 18 volts and a minimum at about 9 volts. The curve for hydrogen shows no maximum, the coefficient increasing steadily down to 2 volts.

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Additional Information:© 1925 The American Physical Society. Received 31 October 1924. The author wishes to express his indebtedness to Dr. R. A. Millikan for suggesting this investigation and for his interest throughout the work.
Issue or Number:5
Record Number:CaltechAUTHORS:BROpr25
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3812
Deposited By: Tony Diaz
Deposited On:12 Jul 2006
Last Modified:12 Dec 2019 17:06

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