THE ORELA POSITRON-SCATTERING PROGRAM - PROGRESS IN THE FIRST ENERGY-ANALYSIS EXPERIMENTS

Implantation and fragmentation by positron impact have been extensivel y studied by the positron group at Oak Ridge National Laboratory, but the group has never attempted an energy analysis of the ions produced. In this contribution, we report on the status of the first energy-ana lysis experiments planned with the ORELA (Oak Ridge Electron Linear Ac celerator) positron beam. These first experiments will be similar to t he original ORELA ionization-fragmentation experiments in that the tar get molecules will be in a stagnant gas, and the positrons will be con fined in a Penning trap. We plan (i) to measure binding energies of se veral positronium compounds, (ii) to measure the energies of fragment ions produced by positrons with energies below fragmentation threshold s, and (iii) to detect secondary electrons from processes following th e formation of ions, and to measure their energies.