Improved low-energy, electron-spin-polarized He+4 ion source

Abstract

Recent improvements to a source of electron-spin-polarized He+4 ions based on an optically pumped, rf-excited helium discharge are described that have resulted in ion polarizations P+ of ∼0.18 at currents of ∼1 nA and in an increase of over an order of magnitude in the quality factor P+2I.

Spin-polarized ion scattering spectroscopy of CCl4 adsorption on Fe(001) surfaces

“…The spin-polarized He + ions were generated from Penning ionization of spin-polarized He 2 3 S 1 atoms (He * ), which were generated in an RF discharge [15,16]. The spin polarization of He * was performed by optical pumping (OP) [17].…”

Development of Spin-Polarized Ion Scattering Spectroscopy

“…SP-ISS, using electron-spin-polarized 4 He + ions, was developed as a novel analytical method for spin arrangement (magnetic structure) at surfaces and interfaces. It was observed that the polarization of OP radiation, which is used to generate spinpolarized He + ions, greatly affected PHe + especially in the high density range of OP radiation.…”

“…The central component for the generation of electron spinpolarized 4 He + ions is Penning ionization of spin-polarized metastable He 2 3 S1 and 2 1 S0 atoms (He*) 4 :…”

“…Very recently, we have shown a possible analysis for spin arrangements at outermost surfaces by spin-polarized ion scattering spectroscopy (SP-ISS) using an electron-spinpolarized 4 He + ion beam. 1 We briefly reported the elementselective spin state analysis at Fe(100) outermost surfaces exposed to an oxygen atmosphere in our first paper on SP-ISS.…”

The dynamics of He+ ion neutralization at a xenon film: Energy- and spin-resolved studies

“…The present apparatus is described in detail elsewhere [4][5][6]11,12]. Briefly, spin-polarized He + ions extracted from an optically-pumped rf-excited helium discharge are formed into a beam by a series of electrostatic lenses and directed onto the target surface at an angle of incidence of h $ 45°to the surface normal.…”