WFC3: Understanding and Mitigating UVIS Charge Transfer Efficiency Losses and IR Persistence Effects
Abstract
A panchromatic instrument, Wide Field Camera 3 (WFC3) contains a UVIS channel with a 4096x4096 pixel e2v CCD array as well as an IR channel with a 1014x1014 Rockwell Scientific HgCdTe focal plane array (FPA). Both detectors have been performing well on-orbit since the installation of the instrument in the Hubble Space Telescope (HST) in May 2009. However, as expected, the harsh low-earth orbit environment has been damaging the UVIS CCDs, resulting in a progressive loss of charge transfer efficiency (CTE) over time. We summarize the magnitude of the CTE losses, the effect on science data, and the pre- and post-observation mitigation options available. The IR FPA does not suffer from accumulating radiation damage but it does exhibit persistence i.e. an after-glow from sources in previous exposures, an anomaly commonly seen in these types of IR arrays. We summarize the characteristics of persistence in WFC3, suggest methods for reducing the effects during observation planning, and describe the calibration products which are available via the Mikulski Archive for Space Telescopes (MAST) for addressing persistence in IR science data.
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22314903B