  Absolute photoionization cross-section measurements are reported for Se+ in
the photon energy range 18.0-31.0 eV, which spans the ionization thresholds of
the 4S_{3/2} ground state and the low-lying 2P_{3/2,1/2} and 2D_{5/2,3/2}
metastable states. The measurements were performed using the Advanced Light
Source synchrotron radiation facility. Strong photoexcitation-autoionization
resonances due to 4p-->nd transitions are seen in the cross-section spectrum
and identified with a quantum-defect analysis.
