27 September 1999 Construction and testing of the wavefront sensor camera for the new MMT adaptive optics system
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This paper describes the construction and testing of the Shack-Hartmann wavefront sensor camera for the new MMT adaptive optics system. Construction and use of the sensor is greatly simplified by having the 12 X 12 lenslet array permanently glued to the detector array, obviating the need for any further realignment. The detector is a frame transfer CCD made by EEV with 80 by 80 pixels, each 24 microns square, and 4 output amplifiers operated simultaneously. 3 by 3 pixel binning is used to create in effect an array of quad-cells, each centered on a spot formed by a lenslet. Centration of the lenslet images is measured to have an accuracy of 1 micrometers rms. The maximum frame rate in the binned mode is 625 Hz, when the rms noise is 4.5-5 electrons. In use at the telescope, the guide star entering the wavefront sensor passes through a 2.4 arcsec squares field stop matched to the quall-cell size, and each lenslet samples a 54 cm square segment of the atmospherically aberrated wavefront to form a guide star image at a plate scale of 60 micrometers /arcsec. Charge diffusion between adjacent detector pixels is small: the signal modulation in 0.7 arcsec seeing is reduced by only 10 percent compared to an ideal quad-cell with perfectly sharp boundaries.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Patrick C. McGuire, Patrick C. McGuire, Troy A. Rhoadarmer, Troy A. Rhoadarmer, Michael Lloyd-Hart, Michael Lloyd-Hart, J. C. Shelton, J. C. Shelton, Michael P. Lesser, Michael P. Lesser, James Roger P. Angel, James Roger P. Angel, George Z. Angeli, George Z. Angeli, John M. Hughes, John M. Hughes, Bruce C. Fitz-Patrick, Bruce C. Fitz-Patrick, Matthew J. Rademacher, Matthew J. Rademacher, Skip Schaller, Skip Schaller, Matthew A. Kenworthy, Matthew A. Kenworthy, Francois P. Wildi, Francois P. Wildi, Jeff G. Capara, Jeff G. Capara, David B. Ouellette, David B. Ouellette, } "Construction and testing of the wavefront sensor camera for the new MMT adaptive optics system", Proc. SPIE 3762, Adaptive Optics Systems and Technology, (27 September 1999); doi: 10.1117/12.363583; https://doi.org/10.1117/12.363583


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