|Author||Hughes, R. H. ♦ Waring, R. C. ♦ Fan, C. Y.|
|Source||United States Department of Energy Office of Scientific and Technical Information|
|Subject Keyword||PHYSICS ♦ CAPTURE ♦ CROSS SECTIONS ♦ DOPPLER EFFECT ♦ ELECTRIC CHARGES ♦ ELECTRONS ♦ ENERGY ♦ ENERGY LEVELS ♦ ERRORS ♦ EXCITATION ♦ HELIUM ♦ HYDROGEN ♦ INTERACTIONS ♦ IONIZATION ♦ IONS ♦ MULTIPLETS ♦ PRESSURE ♦ PROTON BEAMS ♦ PROTONS ♦ QUANTITATIVE ANALYSIS ♦ SPECTRA ♦ SPECTRAL SHIFT ♦ VELOCITY|
|Abstract||Spectra induced by 200-kev proton impact on helium was observed in the spectral region of lambda 3500 A to lambda 6000 A. /sup 1/S states appear to be strongly excited. Absolute crosssections for the direct excitation of the 4 /sup 1/S and 5 /sup 1/S states of neutral helium were determined as well as the simultaneous ionization and excitation cross-section for helium into the n = 4 state of He/sup +/. Of the more intense lines, only the 2 /sup 1/P-n /sup 1/S lines and the He II lambda 4686 line behaved linearly with pressure within experimental error. Triplet spectra were observed in which the dominant feature was the 2/sup 3/Pn /sup 3/D lines. The populations of the 4 /sup 3/D and 4 /sup 1/D states, in particular, were analyzed as a function of a direct mechanism and collision of the second kind which seem to fit the data fairly well. A very weak Doppler-shifted H/sub i line was detected. If this is interpreted to be produced by charge exchange, then the cross section for electron capture into the n = 4 state of hydrogen is estimated to be of the order of 8 x 10/sup -21/ cm/sup 2/. (auth)|
|Learning Resource Type||Article|
|Publisher Department||Univ. of Arkansas, Fayetteville|
|Organization||Univ. of Arkansas, Fayetteville|
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