Optically sensitive Medipix2 detector for adaptive optics wavefront sensing

✍ Scribed by John Vallerga; Jason McPhate; Anton Tremsin; Oswald Siegmund; Bettina Mikulec; Allan Clark

• Book ID: 103854887
• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 383 KB
• Volume: 546
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2005.03.102

✦ Synopsis

A new hybrid optical detector is described that has many of the attributes desired for the next generation adaptive optics (AO) wavefront sensors. The detector consists of a proximity focused microchannel plate (MCP) read out by multi-pixel application specific integrated circuit (ASIC) chips developed at CERN (''Medipix2'') with individual pixels that amplify, discriminate and count input events. The detector has 256 Â 256 pixels, zero readout noise (photon counting), can be read out at 1 kHz frame rates and is abutable on 3 sides. The Medipix2 readout chips can be electronically shuttered down to a temporal window of a few microseconds with an accuracy of 10 ns. When used in a Shack-Hartmann style wavefront sensor, a detector with 4 Medipix chips should be able to centroid approximately 5000 spots using 7 Â 7 pixel sub-apertures resulting in very linear, off-null error correction terms. The quantum efficiency depends on the optical photocathode chosen for the bandpass of interest.