title: Time of flight spectrometer for background-free positron annihilation induced Auger electron spectroscopy.
abstract: We describe a novel spectrometer designed for positron annihilation induced Auger electron spectroscopy employing a time-of-flight spectrometer. The spectrometer's new configuration enables us to implant monoenergetic positrons with kinetic energies as low as 1.5 eV on the sample while simultaneously allowing for the detection of electrons emitted from the sample surface at kinetic energies ranging from ∼500 eV to 0 eV. The spectrometer's unique characteristics made it possible to perform (a) first experiments demonstrating the direct transition of a positron from an unbound scattering state to a bound surface state and (b) the first experiments demonstrating that Auger electron spectra can be obtained down to 0 eV without the beam induced secondary electron background obscuring the low energy part of the spectra. Data are presented which show alternative means of estimating positron surface state binding energy and background-free Auger spectra.
authors.affiliation: Radiochemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai, India.
authors.forename: S
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: K
authors.initials: K
authors.lastname: Shastry
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: C V
authors.initials: CV
authors.lastname: Anto
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: P V
authors.initials: PV
authors.lastname: Joglekar
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Nadesalingam
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: S
authors.initials: S
authors.lastname: Xie
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: N
authors.initials: N
authors.lastname: Jiang
authors.affiliation: Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA.
authors.forename: A H
authors.initials: AH
authors.lastname: Weiss