positronium velocity spectroscopy

positronium velocity spectroscopy

[‚päz·ə′trō·nē·əm və′läs·əd·ē spek′träs·kə·pē]
(spectroscopy)
A technique in which a solid surface is bombarded with a low-energy monoenergetic positron beam and the velocities of the emitted positronium atoms are measured to determine the energy and momentum spectrum of the density of electron states near the surface.