Sink Pixels in ACS/WFC
Abstract
We investigate the properties of sink pixels in the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) detector. These pixels likely contain extra charge traps and therefore appear anomalously low in images with relatively high backgrounds. We identify sink pixels in the average short (0.5-second) dark image from each monthly anneal cycle, which, since January 2015, have been post-flashed to a background of about 60 e-. Sink pixels can affect the pixels immediately above and below them in the same column, resulting in high downstream pixels and low trails of upstream pixels. We determine typical trail lengths for sink pixels of different depths at various background levels. We create a reference image, one for each anneal cycle since January 2015, that will be used to flag sink pixels and the adjacent affected pixels in science images.
- Publication:
-
Instrument Science Report ACS 2017-1
- Pub Date:
- February 2017
- Bibcode:
- 2017acs..rept....1R
- Keywords:
-
- Hubble Space Telescope;
- HST;
- Space Telescope Science Institute;
- STScI;
- ACS