The ORELA positron-scattering program: Progress in the first energy-analysis experiments

Abstract

Implantation and fragmentation by positron impact have been extensively 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-analysis experiments planned with the ORELA (Oak Ridge Electron Linear Accelerator) positron beam. These first experiments will be similar to the original ORELA ionization–fragmentation experiments in that the target molecules will be in a stagnant gas, and the positrons will be confined in a Penning trap. We plan (i) to measure binding energies of several positronium compounds, (ii) to measure the energies of fragment ions produced by positrons with energies below fragmentation thresholds, and (iii) to detect secondary electrons from processes following the formation of ions, and to measure their energies.