Results of a pnCCD Detector System for High-Speed Optical Imaging

We present the design and optical imaging performance of a pnCCD detector system for highest frame rates and excellent sensitivity over a wide wavelength range from the UV to near IR region. To achieve frame rates higher than one thousand frames per second with an exceptionally low noise level, the devices are based on proven technology with column parallel readout and operated in a split-frame transfer mode. The CCDs are back illuminated and coated with an Anti-Reflective-Coating. The sensitivity over their full thickness of 450 mu m allows for a quantum efficiency near 100% over a wide spectral range. At an optical test bench we determined the photon transfer curve, quantum efficiency and point-spread function within a wavelength region between 300 rim to 1100 nm for various detector parameter. To demonstrate the ability of a pnCCD to perform high-speed optical differential photometry, the crab nebula with the crab pulsar as central object were observed at the 1.3 m SKINAKAS telescope on crete. For these observations the pnCCD was operated at a speed of 2000 frames per second. The high speed, low noise and high quantum efficiency makes this detector an ideal instrument to be used as a wavefront sensor in adaptive optics systems.