Accession Number : AD0653720

Title :   SCATTERING OF THERMAL ENERGY GAS BEAMS BY METALLIC SURFACES II,

Corporate Author : UNITED AIRCRAFT CORP EAST HARTFORD CONN RESEARCH LABS

Personal Author(s) : Hinchen,John J. ; Malloy,Evelyn S. ; Carroll,James B.

Report Date : JUN 1967

Pagination or Media Count : 99

Abstract : Scattering of molecular gases from platinum and tantalum was studied using an ultra-high vacuum molecular beam apparatus. Beams of the rare gases, nitrogen, oxygen, methane and water vapor were used. The angle of maximum intensity of the scattered gas beams had a dependency on experimental variables that was in fair agreement with theory. Surface contamination and roughness affected the intensity and spatial distribution of scattered beams, but no difference between polycrystalline and single crystal metal surfaces was observed. By using phase-sensitive-detection techniques, the velocity of scattered molecules was found to vary with angular position about the surface. Energy and momentum coefficients were evaluated from the experimental data. Under certain conditions, discontinuities and negative values were found for these coefficients; such excursions in energy accommodation have been theoretically predicted. The experimental results were used in analysis of free molecule and slip flows. (Author)

Descriptors :   (*SCATTERING, *MOLECULAR BEAMS), (*RARE GASES, MOLECULAR BEAMS), (*VACUUM APPARATUS, MOLECULAR BEAMS), PLATINUM, INTENSITY, TANTALUM, SURFACE ROUGHNESS, CONTAMINATION, THEORY, ELECTRON MICROSCOPY, HEAT TRANSFER, NITROGEN, OXYGEN, METHANE, WATER VAPOR, MOMENTUM, SPACE FLIGHT, METALS, X RAY DIFFRACTION

Subject Categories : Physical Chemistry
      Particle Accelerators
      Astronautics

Distribution Statement : APPROVED FOR PUBLIC RELEASE