Location
University of Utah
Start Date
5-13-2002 2:10 PM
Description
The dynamics of low energy atomic collision and ionization processes at surfaces are under investigation for satellite applications. Atomic scattering experiments have been performed under high vacuum conditions (~10-8 Torr) similar to those encountered in space environments. Experimental results indicate that energy loss in fact depends on the charge state of the incident atom. Measurements have been accomplished for all charge states of atomic hydrogen (H+, H-, H) impacting a copper surface and scattering as H-. Energy and angular distributions of scattered H- are presented here for collision energies ranging from 25-200 eV. All scattered H- energy distributions exhibit a broadened peak associated with inelastic collisions followed by charge exchange. However, for collision energies less than ~100 eV, the charge state of the incident atom has measurable effects on the energy distributions of resulting H-. These H- energy distributions resulting from incident H+ and H are similar, however the apparent threshold energies differ by 4.7 +/- 0.5 eV. In addition, the energy distributions of scattered H- resulting from incident H- exhibit a secondary peak attributed to ion survival.
An Investigation of Charge State Effects in Atom-Surface Scattering
University of Utah
The dynamics of low energy atomic collision and ionization processes at surfaces are under investigation for satellite applications. Atomic scattering experiments have been performed under high vacuum conditions (~10-8 Torr) similar to those encountered in space environments. Experimental results indicate that energy loss in fact depends on the charge state of the incident atom. Measurements have been accomplished for all charge states of atomic hydrogen (H+, H-, H) impacting a copper surface and scattering as H-. Energy and angular distributions of scattered H- are presented here for collision energies ranging from 25-200 eV. All scattered H- energy distributions exhibit a broadened peak associated with inelastic collisions followed by charge exchange. However, for collision energies less than ~100 eV, the charge state of the incident atom has measurable effects on the energy distributions of resulting H-. These H- energy distributions resulting from incident H+ and H are similar, however the apparent threshold energies differ by 4.7 +/- 0.5 eV. In addition, the energy distributions of scattered H- resulting from incident H- exhibit a secondary peak attributed to ion survival.