title: Molecular ion source having low energy spread and single-electron-impact excitation.
abstract: A cylindrically symmetric electron-bombardment ion source is described that has been useful in beam experiments with molecular ions. Measurements indicate that the ions have a kinetic-energy spread (full-width at half-maximum) of 0.5-1.0 eV, a current of several microamperes, and a population distribution that is consistent with vibrational and rotational factors resulting from single-electron-impact ionization. The source exhibits low noise ( less, similar twice the theoretical shot-noise limit) and has a compact and easily serviceable construction.
authors.affiliation: Department of Physics, University of Arizona, Tucson, Arizona 85721Physics Department, Bates College, Lewiston, Maine 04240Department of Physics and Optical Sciences Center, University of Arizona, Tucson, Arizona 85721.
authors.forename: J J
authors.initials: JJ
authors.lastname: Spezeski
authors.forename: G A
authors.initials: GA
authors.lastname: Ruff
authors.forename: W H
authors.initials: WH
authors.lastname: Wing