Energy Resolution – FWHM vs Pass Energy

 

For Hemi-spherical Analyzer (HSA) and Electron Collection Lens

NOTE:    FWHM of Ag (3d5/2) is used to Define Energy Resolution

  • Survey Spectrum Energy Resolution:                                  FWHM (eV) for Ag (3d5/2) = 1.5 eV using Pass Energy = 150 eV
  • Usual Chemical Compound Energy Resolution:                  FWHM (eV) for Main Peak = 1.0 – 1.2 eV using Pass Energy = 50 eV
  • Chemical State Spectrum Energy Resolution:                     FWHM (eV) for Ag (3d5/2) = 0.75 eV using Pass Energy = 50 eV
  • Ultimate Energy Resolution for a Conductor:                       FWHM (eV) for Re (4f7/2) = 0.35 eV using Pass Energy = 25 eV
  • Ultimate Energy Resolution of Hemispherical Analyzer:      FWHM (eV) = 0.25 eV  using Pass Energy = 10 eV
  • Theoretical FWHM (eV) of Monochromatic Al Kα X-rays:    FWHM (eV) = 0.16 eV
  • FWHM is measured before any Argon ion etching of chemical compounds because etching can degrade chemical states of compounds
  • FWHM of pure chemical elements are measured after Argon ion etching which removes metal oxides that have FWHM larger than the pure metal