Measurement of the absolute spectral response of an inverse photoemission detector

The absolute quantum yield of an inverse photoemission detector is reported. The detector consists of a 650-Å KBr photoemission film on the mouth of a channeltron with either a CaF2 or a SrF2 window for a low-pass cutoff filter. The spectral response for the CaF2 window peaks at 9.8 eV with a FWHM of 1.6 eV and a maximum yield of 0.18 pulse/photon, while for the SrF2 window the peak is at 9.3 eV with a FWHM of 1.4 eV and a maximal yield of 0.06 pulse/photon. Performance of the detector was tested by measuring the inverse photoemission spectra from a W(001)-(1×1) surface.