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Expulsion of Neutrons from Lead by Cosmic Rays


A NEUTRON counter was made of a brass tube 10 cm. long and 1 cm. in diameter, the inner surface being coated with a thin film of borate a few microns thick. The axial collector of the ionization chamber was directly connected to a set of the improved linear amplifier system, which was so carefully mounted that the counting system was perfectly free from the mechanical and electrical disturbances of the surroundings, and gave only two to four clear, natural kicks in an hour. By a series of control experiments with neutrons from a radium-beryllium source (of 10 mgm. radium), it was found very reliable for observing slight variations in the number of kicks under various experimental conditions.

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  1. “Kernphysik”, edited by E. Bretscher, p. 108 ( E. J. Williams ) (Berlin: Julius Springer, 1936).

  2. Bothe, W., and Gentner, W., Naturwiss., 25, 90 and 126 (1937).

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  3. Fünfer, E., Naturwiss., 25, 235 (1937).

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ARAKATSU, B., KIMURA, K. & UEMURA, Y. Expulsion of Neutrons from Lead by Cosmic Rays. Nature 140, 277–278 (1937).

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