Our Mission Visible detectors fully matching the requirements of Adaptive Optics wavefront sensors for 10m class telescopes do not yet exist: current detectors have frame rates which are too slow and which are too noisy for the second generation of AO systems. The visible detectors developed by this JRA will be dedicated to AO applications. The scalability of these detectors for ELT AO systems will be taken into account. Philippe Feautrier JRA2 Principal Investigator Laboratoire d’Astrophysique Observatoire de Grenoble Domaine Universitaire 414 rue de la piscine, BP Grenoble Cedex 9 France Telephone: +33 (0) grenoble.fr Contact OPTICON - The Optical Infrared Coordination Network for Astronomy JRA2 – Fast Detectors for Adaptive Optics OPTICON is funded by the European Commission under Contract RII3-CT The participants will attempt to define, fabricate and fully characterize the best possible detector working at visible wavelengths which is suitable for wavefront sensors in Adaptive Optics (AO) systems. This Joint Research Activity is closely linked to JRA1 - Adaptive Optics. This will ensure that this detector development follows the AO requirements in terms of wavefront sensing detectors. The detector format should be 256x256 pixels, the frame rate must be very fast (up to 2 kHz) while the readout noise must be kept extremely low (typically below 3e-). Fast Detector for AO: the need The next generation of Adaptive Optics systems for 8 to 10-m class telescopes will require an increased number of degrees of freedom, which will increase the number of actuators required typically by a factor of 5 to 10. Existing CCD’s will not allow production of the corresponding wavefront sensors. The success of such new AO concepts will therefore strongly depend on new developments in the field of visible wavefront sensor detectors, both in terms of usable number of pixels and increased sensitivity. Participants The 7 collaborating organisations are: Laboratoire d’Astrophysique de Grenoble Laboratoire d’Astrophysique de Marseille Observatoire de Haute Provence Instituto de Astrofisica de Canarias ESO ONERA Observatoire Midi-Pyrénées c/o ESO: the NAOS visible wavefront sensor Block diagram of a simple AO system Detector technologies and specifications A non-exhaustive list of possible detector technologies is: 1.Single direction or split frame transfer CCD with a large number (up to 512) of output amplifiers that are read out at moderate to low speed. A possible output amplifier configuration is one amplifier per detector column. 2.Single direction or split frame transfer CCD with a small number of output amplifiers that are read out at high speed. To meet low read noise requirements, the devices will use special techniques such as electron multiplication CCD technology to amplify the signal and reduce effective output amplifier read noise. 3.Direct readout device (hybrid, CMOS) where the detector will be coupled to a readout multiplexer. A Call For Tender was started in July 2004 in order to choose the detector manufacturer. Now this choice has been made, the detector is being fabricated and fully tested, at first by the manufacturer and soon after by the partners of the JRA2. The main output of the JRA2 will be the test report of the detector produced in the context of AO systems for 10m class telescopes