Reynolds, H. K. and Dunbar, D. N. F. and Wenzel, W. A. and Whaling, W. (1953) The stopping cross section of gases for protons, 30-600 kev. Physical Review, 92 (3). pp. 742-748. ISSN 0031-899X http://resolver.caltech.edu/CaltechAUTHORS:REYpr53
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The stopping cross section of H2, He, O2, air, N2, Ne, A, Kr, Xe, H2O, NH3, NO, N2O, CH4, C2H2, C2H4, and C6H6 for protons has been measured over the energy range Ep=30-600 kev. An electrostatic analyzer measures the energy of protons incident on a gas cell, and the transmitted beam energy is measured with a magnetic spectrometer. The gas cell is closed off with thin aluminum windows. Comparison of the molecular stopping cross section of the compounds with the values obtained by summing the constituent atomic cross sections shows that Bragg's rule does not hold for any of these compounds below Ep=150 kev; for NO the additive rule does not hold at any energy studied. Above 150 kev the stopping cross section of carbon is obtained by subtracting the hydrogen contribution from the values measured for the hydrocarbons. Average ionization potentials are calculated from these measurements. A range energy relation for protons in air is included. Sources of error are discussed; the probable error of the stopping cross section measurements varies between 2-4 percent.
|Additional Information:||©1953 The American Physical Society. Received 27 July 1953. We are indebted to Professor Christy for many interesting discussions of the energy loss problem. Supported in part by the joint program of the U.S. Office of Naval Research and the U.S. Atomic Energy Commission.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||16 Nov 2006|
|Last Modified:||26 Dec 2012 09:17|
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