| Popis: |
Measured absolute detection efficiencies are presented for H, H − and H n + ( n =1,2,3) impacting a commercially available, dual multichannel plate (MCP) electron multiplier at kinetic energies ranging from 30 to 1000 eV. Measurements involving isotopic substitutions (D, D − , D n + ) and Ar + are also presented. In addition, atomic hydrogen detection efficiencies relative to those of H + and H − are given, as they may have a more universal application. For the three charge states, H, H + and H − , the absolute detection efficiencies are markedly different at low energies and converge to a nearly uniform value of ∼70% with increasing projectile energy. The energy dependence is strongest for H + , varying nearly three orders of magnitude over the energy range studied, and weakest for H − , varying by less than one order of magnitude. In general, for the low energy positive ions at a given energy, the lighter the incident particle mass, the greater the probability of its detection. |
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