The relation between the trapped ion density achieved in a machine like OGRA and the molecular ion injection current required, the "S-curve" calculated by Simon, has been extended to include the effect of energy transfer from trapped ions to the continuous flux of cold electrons released in the ionization of the neutral background. Because the cross section for charge exchange, the process by which ions are lost before "burnout," increases sharply with decrease in energy, even a little degradation greatly increases the ion loss rate and thereby increases the injection current required to sustain a given density. Our revised result for the critical current for burnout determined from the S-curve, is about twice that calculated neglecting ion energy degradation for the case of injecting 600 Kev H+2. In the report, we present new S-curves, and the critical current for a range of H+2 injection energies from 500 Kev to 800 Kev.
展开▼
