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High speed wide field CMOS camera for Transneptunian Automatic Occultation Survey

2014; SPIE; Volume: 9147; Linguagem: Inglês

10.1117/12.2055606

1996-756X

Shiang‐Yu Wang, John C. Geary, Stephen M. Amato, Yen-Sang Hu, Hung-Hsu Ling, Pin-Jie Huang, Gábor Fűrész, Hsin-Yo Chen, Yin-Chang Chang, Andrew Szentgyorgyi, M. J. Lehner, Timothy Norton,

Geomagnetism and Paleomagnetism Studies

The Transneptunian Automated Occultation Survey (TAOS II) is a three robotic telescope project to detect the stellar occultation events generated by Trans Neptunian Objects (TNOs). TAOS II project aims to monitor about 10000 stars simultaneously at 20Hz to enable statistically significant event rate. The TAOS II camera is designed to cover the 1.7 degree diameter field of view (FoV) of the 1.3m telescope with 10 mosaic 4.5kx2k CMOS sensors. The new CMOS sensor has a back illumination thinned structure and high sensitivity to provide similar performance to that of the backillumination thinned CCDs. The sensor provides two parallel and eight serial decoders so the region of interests can be addressed and read out separately through different output channels efficiently. The pixel scale is about 0.6"/pix with the 16μm pixels. The sensors, mounted on a single Invar plate, are cooled to the operation temperature of about 200K by a cryogenic cooler. The Invar plate is connected to the dewar body through a supporting ring with three G10 bipods. The deformation of the cold plate is less than 10μm to ensure the sensor surface is always within ±40μm of focus range. The control electronics consists of analog part and a Xilinx FPGA based digital circuit. For each field star, 8×8 pixels box will be readout. The pixel rate for each channel is about 1Mpix/s and the total pixel rate for each camera is about 80Mpix/s. The FPGA module will calculate the total flux and also the centroid coordinates for every field star in each exposure.