The secondary electron energy distributions for a gold photocathode as excited by CK&agr;(277 eV) and AlK&agr;(1487 eV) x rays have been measured. The shapes of the energy distributions are essentially the same for these two x‐ray photon excitation energies. For thick evaporated gold samples on glass substrates (at 150 °C and 3×10−8Torr), the secondary electron energy distributions peak at about 1 eV and have a FWHM of about 4 eV. As measured immediately after ion cleaning, the distributions peak at about 2 eV and have a FWHM of about 6.6 eV. Approximately 5 h after ion cleaning, the measured distributions appear as those obtained before ion cleaning. The work function of the evaporated gold photocathode temporarily increases by 1 eV upon ion cleaning.