ROSAT WFC imaging detectors

Results of the calibration program performed on flight and flight-spare detectors for the Rosat Wide Field Camera (WFC) are presented. The result of an accelerated life test on a development model detector assembled to flight standard are summarized. Imaging tests demonstrate that the lookup table technique for removing distortion works efficiency with low differential nonlinearity. No undesirable 'chicken wire' effects are seen in the images, and the detector resolution matches the on-axis performance of the telescope and is constant across the field of view. Peaks in efficiency occur at 10.2, 20, and 100 eV and mimima at 13 and 45 eV. The secondary 13 eV minimum is correlated with the onset of two-electron photoemission. The mean change in gain as a function of photon energy in the EUV band is much less rapid than in the soft X-ray band.