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We present the dedicated controller in development for the OPTICON JRA2 programme "Fast Visible Detectors for Adaptive Optics" (1). The CCD developed within this programme is a highly specialized chip using e2v's Low Light Level Charge Coupled Device (L3CCD) technology capable of outstanding capabilities (2). It is not possible to extrapolate existing controller techniques since the chip needs radiofrequency signals (more than 10 MHz) for clocking, and gives a high frequency video output. Compactness is of prime importance to deal with these high frequency signals and is also important for future integration in next generation adaptive optics systems. Developing such a controller is very challenging and needs to utilize innovative techniques to fulfill the requirements. We will summarize the JRA2 and detector requirements, derive the controller requirements, present guidelines of the controller, and highlight the challenges of this controler.

ESO and JRA2 OPTICON have funded the development of a compact packaged Peltier cooled 24 µm square 240×240 pixel split frame transfer 8-output back illuminated L3Vision CCD, L3CCD, by e2v technologies. The device will achieve sub-electron (goal 0.1e - ) read noise at frame rates from 25 Hz to 1.5 kHz and low dark current of 0.01 e - /pixel/frame. The development has many unique features. To obtain high frame rates, multi-output EMCCD gain registers and metal buttressing of parallel clocks will be used. To minimize risk, the baseline device will be built in standard silicon. In addition, a split wafer run will enable two speculative variants to be built; deep depletion silicon devices to improve red response and devices with an electronic shutter to extend use to Rayleigh Laser Guide Star (RLGS) applications. These are all unprecedented advancements for L3CCDs. This paper will describe requirements and outline the design established after careful consideration of the application, detector architecture, compact Peltier package, technology trade-offs, schedule and proposed test plan.

The NAOS adaptive optics system was installed in December 2001 on the Nasmyth focus of the ESO VLT. It includes two wavefront sensors: one is working at IR wavelength analysis and the other at visible wavelengths. This paper describes the NAOS Visible Wave Front Sensor based on a Shack-Hartman principle and its performances as measured on the sky. This wavefront sensor includes within a continuous flow liquid nitrogen cryostat: 1) a low noise fast readout CCD camera controlled by the ESO new generation CCD system FIERA using a fast frame rate EEV/Marconi CCD-50 focal plane array. This 128×128 pixels focal plane array has a readout noise of 3 e- at 50 kilopixel/sec/port. FIERA provides remotely controlled readout modes with optional binning, windowing and flexible integration time. 2) two remotely exchangeable micro-lens arrays (14×14 and 7×7 micro-lenses) cooled at the CCD temperature ( -100 °C) within the cryostat. The CCD array is directly located in the micro lenses focal plane at a few millimeters apart without relay optics. 3) Additional opto-mechanical functions are also provided (atmospheric dispersion compensator, flux level control, field of view limitation). On sky performances of the wavefront sensor are presented. Adaptive Optics corrections was obtained with a reference star as faint as a visible magnitude 17 with a band-path of 40 Hz in close loop.