Rates and Mechanisms of Metastable Deactivation over Surfaces
Final rept. Nov 1985-Dec 1988,
PHYSICAL SCIENCES INC ANDOVER MA
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The objective of this project was to investigate mechanisms of energy disposal in the quenching of rare gas and molecular metastable species upon collisions with practical surfaces representative of plasma reactors. An apparatus was designed and constructed to generate a molecular beam of selected metastable species He, Ar, N2 and impinge the beam on clean or gas-dosed surfaces in an ultra high vacuum UHV chamber. The metastables were generated in a discharge-flow reactor, sampled and skimmed into a molecular beam, and directed into the UHV target chamber via two-stage differential pumping. A hemispherical, retarding potential electron energy analyzer was used to measure production rates and energy distributions of electrons ejected from the surface via the Penning ionization and Auger neutralization quenching mechanisms. The absence of significant electron ejection from metastable impingement is quite unexpected in light of previous investigations of this process for polished, high-purity, oriented single crystals.
- Atomic and Molecular Physics and Spectroscopy