First measurements with a frame store PN-CCD X-ray detector

The PN-CCD camera on the XMM-Newton X-ray astronomy satellite is the most advanced X-ray spectrometer combining high quantum efficiency, high-speed readout and excellent energy resolution. According to the fullframe concept, the whole 6×6 cm2 large CCD-chip area is used as image area, i.e. is sensitive and exposed to X-rays. The camera operates since January 2000 successfully in space without performance degradation. Based on the concept and technology development of the XMM-Newton PN-CCD, the ‘frame store PN-CCD’, a further development of the detector has been proposed. For the new detector a frame store area is added, adjacent to the image area, to allow in parallel photon exposure in the image area and signal readout of the previous image in the frame store area. The concept and the new features of the device will be described here. This comprises in particular a reduced probability of out-of-time event occurrence, the optimization of electronic noise and charge transfer losses as well as a method to obtain a cleaner low-energy response. The first measurements with the new frame store PN-CCD are presented with focus on the above addressed detector parameters. It is planned to apply the device as focal plane instrument for the ROSITA mission that has the aim to extend the ROSAT all-sky survey towards higher energies.