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CCD News (1Sep94) (from CTIO, NOAO Newsletter No. 39, 1 September 1994) Our second Tektronix (SITe) 2048 CCD was commissioned during June and has subsequently seen use at the 0.9-m and 4-m telescopes. For historical reasons our two Tek 2048 CCDs are known as #3 and #4; the CCD being described here is #4. The new CCD is nearly perfect. It has no imaging area defects, excellent charge transfer, all four amplifiers operate with low noise, full-well is almost double that of #3, and dark rate is very low. Various parameters are given in the table below. The QE figures are preliminary, and the actual values may be even better, especially in the UV. The CCD is operated by an Arcon CCD controller, which reads all four amplifiers simultaneously and can deliver a 5 e- rms read-noise picture in 30 seconds. For spectroscopic applications a read-noise of 3 e- rms is possible, with a read-time of only one minute. As announced previously (Newsletter No. 38, p. 20), for semester 2 1994 Tek 2048 #3 will be dedicated to the 0.9-m telescope. Tek 2048 #4 will see use for direct imaging at the 4-m and 1.5-m, and on the Echelle spectrographs of these telescopes. Tek 2048 #4 CCD size: 2048 X 2048 Pixel size: 24 um QE (3000 A): 25% QE (4000 A): 60% QE (5000 A): 75% QE (6000 A): 75% QE (7000 A): 75% QE (8000 A): 65% QE (9000 A): 30% Full well: 300000 e- Gain, RN: 4.0 e-/adu, 4.8 e- RN, 30s readout 2.9 e-/adu, 4.0 e- RN, 34s readout 2.0 e-/adu, 3.5 e- RN, 40s readout 1.3 e-/adu, 3.2 e- RN, 50s readout 1.0 e-/adu, 3.0 e- RN, 60s readout Dark: Less than 3 e-/pixel/hour Alistair Walker
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