Evidence for Fast Positronium Formation in Glancing Angle Positron Scattering

摘要

We have evidence for fast (10-100 eV) positronium formation when 30 to 300 eV positrons scatter off an Al(110) surface at glancing angles as low as 6 deg with respect to the surface. A doubly remoderated, brightness enhanced positron beam of 1 mm diameter and 1 deg opening angle is used. A position sensitive CEMA is biased to detect only neutral particles. As evidence of fast Ps formation, we will present incident beam energy scans of the neutral particle counting rate as well as position sensitive plots of the angular formation probability. (ERA citation 11:021228)