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|Title:||Measurement of charge transfer cross sections for high energy (~1 MeV) protons and hydrogen atoms incident upon hydrogen and helium gases.|
|Publisher:||Australian Nuclear Science and Technology Organisation|
|Abstract:||Measurements of the single and double electron capture cross sections for protons, σ1o and σ 1-1 respectively and the single electron loss cross section for hydrogen atoms σo1, within the energy range 0.25 to 2.5 MeV for hydrogen and helium target gases are reported and compared with published theoretical estimates and experimental values. The present values of σ1o and σo1 agree well with the data of Barnett and Reynolds below 1 MeV. The extrapolation of the data of Barnett and Reynolds to pass through the single value at 10 MeV by Berkner is confirmed. The experimental values of σoi agree with calculations that use the Born and free-collision approximations within the experimental uncertainty of ± 10 per cent. The values of σ1-1 decrease from 5.1 x 10-25 cm2/mol at 0.4 MeV to 1.6 x 10—28 cm2/mol at 1.0 MeV with an experimental uncertainty of up to a maximum of 60 per cent. These values are lower than, but exhibit a similar dependence upon proton energy to the first Born approximation calculations by Mittleman. A detailed discussion is given of the experimental accuracy which was based upon a procedure previously devised by the author. The cross sections were measured by the method of observing the rate of growth with target gas number density of the fast collision products from an originally pure primary beam. This method is more accurate than the methods used by other workers. The apparatus was developed for use at pressures less than 10-8 mmHg by baking at 400°C. It was designed for measuring a wide variety of charge changing collisions.|
|Gov't Doc #:||301|
|Appears in Collections:||Scientific and Technical Reports|
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