Abstract
Crystalline and amorphous ice were studied with monoenergetic positrons with incident energies keV. Positronium (Ps) forms in the ice and diffuses as a neutral particle until annihilation or escape from the surface. Measurement of the fraction of -Ps leaving the surface reveals two distinct contributions to the total Ps-formation probability (both Ore- and spur-type) as well as the Ps diffusion coefficient, 0.17±0.09 /sec in crystalline ice. In addition, positronium trapping is observed in sputtered (crystalline) ice and voids (≳ 17 Å diameter) in amorphous ice.
- Received 20 July 1983
DOI:https://doi.org/10.1103/PhysRevLett.51.2007
©1983 American Physical Society