The cross sections for positron impact ionization of atomic hydrogen have been measured from close to threshold up to a kinetic energy of 700 eV and compared to similar data for electron projectiles. The positron values are found to exceed those for electrons at intermediate energies by around 40%, in accord with several recent theories.
Following from the measurement of the ionization cross section the apparatus will be modified to allow the investigation of positronium formation. Antiparticle atomic hydrogen investigations will be extended to the antiproton projectile.
It is proposed that existing technologies of low energy e+ beams and radio-frequency discharge H atom beam sources be combined to study e+ -H scattering. Some reactions of this important three body system, namely ionisation and positronium formation, can be readily studied and will offer new tests of fundamental scattering theory.
Funding SchemeCSC - Cost-sharing contracts