Production, Characterization, and Measurement of H(D) Beams on the ORNL Merged-Beams Experiment

Total cross section measurements of electron capture processes are being studied for low-energy, Aq++H(D) collisions using the Ion-Atom Merged-Beams apparatus at the Multicharged Ion Research Facility (MIRF) at Oak Ridge National Laboratory (ORNL). On this apparatus, a modified Faraday cup detector is used to measure the intensity of the neutral beam. The conversion of the measured electrical current to the true neutral particle beam current is necessary to accurately determine the true cross section values. Inherent in this conversion process is the number of secondary electrons (g) emitted from the surface of the detector upon impact of an atom. The method employed to determine g and its role in the absolute electron capture measurements at ORNL-MIRF are presented. With a recent upgrade to the apparatus, the neutral beam H(D) production technique has been improved and is discussed in detail in this paper.