Section 7: Summary

On Saturday 13 April 1996, the CFHT CCD STIS2 was found to have the following properties in the lab in Waimea:

• Readout noise is 8.7 electrons/pixel
• There is no detectable coherent interference noise
• The electronic conversion factor is 4.56 electrons/pixel
• The dark current ranges from <10^-2 electrons/pixel/sec in the center of the CCD imaging area to >3x10^-2 electrons/pixel/sec at the corners
• The mean bias level is 1516 ADU
• The bias overscan region is not an accurate measure of the bias structure over the whole CCD image, but may be used to calibrate a bias image for use in astronomical reductions.
• The last physical bias overscan pixel in the serial register shows anomolously high counts and should not be used in data reduction.
• The CCD has a linear response to within 0.04%. No shutter was involved in this measurement.
• Two hot pixels, whose effect appears to be removed with bias subtraction, were noted at pixels (635,1975) and (637,1975).
• Another hot column starting at pixel (1817,43) is not removed on bias subtraction.
• A trap, centered at pixel (860,793) destroys all data in the column above it.
• There are numerous small dust motes on the CCD (possibly arising from the Carbon getter used in the dewar).
• CTE is better than 0.999 in both horizontal and vertical directions.
• There is some evidence of bit biasing in the A-to-D converter.