Author: Calvin K. LamPublisher:
ISBN:
Category : Molecular beams
Languages : en
Pages : 110
Book Description
A Hypersonic Atomic Oxygen Molecular Beam Source
Author: Calvin K. LamPublisher:
ISBN:
Category : Molecular beams
Languages : en
Pages : 110
Book Description
Development of a Nozzle Beam Containing Atomic Oxygen
Author: Calvin K. LamPublisher:
ISBN:
Category : Molecular beams
Languages : en
Pages : 47
Book Description
Initial studies of the feasibility of producing a hypersonic molecular beam containing appreciable amount of atomic oxygen have been successfully completed. The purpose of the work was to produce a molecular beam which could be used for basic and applied studies related to the interaction of the earth's upper atmosphere, such as accommodation coefficient measurements or surface reactions at high kinetic energy. A quartz tube source was developed for the molecular beam in which a 200 watt microwave discharge could be maintained. The studies included the effect of pressure and orifice size, for which a compromise was involved in order to achieve high Mach numbers and high dissociation levels, the use of double cavities, and the effect of small additions of H2O. It was demonstrated in these initial tests that a hypersonic beam from a 92% He 8% O2 mixture could be produced with 17% dissociation. (Author).
Development of a Supersonic Atomic Oxygen Nozzle Beam Source for Crossed Beam Scattering Experiments
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A high pressure, supersonic, radio frequency discharge nozzle beam source was developed for the production of intense beams of ground state oxygen atoms. An efficient impedance matching scheme was devised for coupling the radio frequency power to the plasma as a function of both gas pressure and composition. Techniques for localizing the discharge directly behind the orifice of a water-cooled quartz nozzle were also developed. The above combine to yield an atomic oxygen beam source which produces high molecular dissociation in oxygen seeded rare gas mixtures at total pressures up to 200 torr: 80 to 90% dissociation for oxygen/argon mixtures and 60 to 70% for oxygen/helium mixtures. Atomic oxygen intensities are found to be greater than 1017 atom sr−1 sec−1. A brief discussion of the reaction dynamics of 0 + IC1 .-->. I0 + C1 is also presented. 12 references.
AN ATOMIC OXYGEN BEAM SYSTEM FOR THE INVESTIGATION OF MASS SPECTROMETER RESPONSE IN THE UPPER ATMOSPHERE
Author: Hasso B. P. NiemannScientific and Technical Aerospace Reports
Author: Molecular Beam Studies of Atomic Oxygen
Author: High Energy-intensity Atomic Oxygen Beam Source for Low Earth Orbit Materials Degradation Studies
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A high intensity (1019O-atoms/s-sr) high energy (5 eV) source of oxygen atoms has been developed that produces a total fluence of 1022 O-atoms/cm2 in less than 100 hours of continuous operation at a distance of 15 cm from the source. The source employs a CW CO2 laser sustained discharge to form a high temperature (15,000 K) plasma in the throat of a 0.3-mm diameter nozzle using 3--8 atmospheres of rare gas/O2 mixtures. Visible and infrared photon flux levels of 1 watt/cm2 have been measured 15 cm downstream of the source while vacuum UV (VUV) fluxes are comparable to that measured in low earth orbit. The reactions of atomic oxygen with kapton, Teflon, silver, and various coatings have been studied. The oxidation of kapton (reaction efficiency = 3 x 10/sup /minus/24/ cm ± 50%) has an activation energy of 0.8 Kcal/mole over the temperature range of 25/degree/C to 100/degree/C at a beam energy of 1.5 eV and produces low molecular weight gas phase reaction products (H2O, NO, CO2). Teflon reacts with approx.0.1--0.2 efficiency to that of kapton at 25/degree/C and both surfaces show a rug-like texture after exposure to the O-atom beam. Angular scattering distribution measurements of O-atoms show a near cosine distribution from reactive surfaces indicating complete accommodation of the translational energy with the surface while a nonreactive surface (nickel oxide) shows specular-like scattering with 50% accommodation of the translational energy with the surface. A technique for simple on orbit chemical experiments using resistance measurements of coated silver strips is described. 9 figs.
Energy Research Abstracts
Author: The Construction of a Neutral Molecular Beam Facility and Its Application to Mass Spectrometers Carried on Space Vehicles
Author: John Otto BallenthinPublisher:
ISBN:
Category :
Languages : en
Pages : 310
Book Description
Author: