  Cathode electrodes of the Si(Li) detector elements of the SIXA X-ray
spectrometer array are formed by gold-palladium alloy contact layers. The
equivalent thickness of gold in one element was measured by observing the
characteristic L-shell X-rays of gold excited by monochromatised synchrotron
radiation with photon energies above the L3 absorption edge of gold. The
results obtained at 4 different photon energies below the L2 edge yield an
average value of 22.4(35) nm which is consistent with the earlier result
extracted from detection efficiency measurements.
  PACS: 29.40.Wk; 85.30.De; 07.85.Nc; 95.55.Ka
  Keywords: Si(Li) detectors, X-ray spectrometers, X-ray fluorescence, detector
calibration, gold electrodes, synchrotron radiation
