Speaker
Description
Wide Field Camera 3 (WFC3) is a fourth-generation imaging instrument installed on the Hubble Space Telescope during Servicing Mission 4 in 2009. WFC3 features two independent channels: the Ultraviolet-Visible channel (UVIS), sensitive to 200-1000 nm, with a pair of ~2K x 4K CCDs, and the Infrared channel (IR), sensitive to near-IR approximately 800-1700 nm, with a ~1K x 1K HgCdTe array. WFC3 has been performing extremely well over its 15 years on-orbit, although each detector has characteristics that can affect the precision of astronomical measurements and thus require calibration. For example, the UVIS CCDs experience charge transfer efficiency losses due to radiation damage from the orbital environment, as well as dark current and hot pixel growth. UVIS also experiences a small number of anomalous pixels referred to as sink pixels and low-level pixel-to-pixel quantum efficiency fluctuations. The IR focal plane array exhibits persistence, hot/bad pixels, and snowballs. All the detector systematics are well-characterized and routinely monitored, with calibration and/or mitigation strategies updated as needed. Here we discuss some of the UVIS and IR detector systematics as well as the pre- and post-observation techniques we employ to mitigate their effects.
Keywords for your contribution subject matter (this will assist SOC in accurately characterizing your contribution)
HgCdTe sensors, photometric and astrometric fidelity
| contribution subject matter | CCD sensors |
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