Wide Field Camera 3 Instrument Handbook for Cycle 19 - Space ...

30 Chapter 5: WFC3 Detector Characteristics and Performance
Table 5.1: WFC3 Detector Characteristics
Characteristic UVIS Channel CCDs IR Channel Detector
Architecture
e2v CCD detectors.
Thinned, backside illuminated,
UV optimized,
multi-phase pinned,
buried/mini-channel, charge
injection capability.
Teledyne HgCdTe infrared detector.
MBE-grown,
substrate removed,
on Si CMOS Hawaii-1R multiplexer.
Wavelength Range 200 to 1000 nm 800 to 1700 nm
Pixel Format 2 butted 2051 × 4096,
31-pixel gap (1.2")
1024 × 1024 (1014 × 1014 active)
Pixel Size 15 μm × 15 μm 18μm × 18 μm
Plate Scale 0.040"/pixel 0.13"/pixel
Field of View on Sky Rhomboidal, 162" × 162" Rectangular, 136" × 123"
Quantum Efficiency 50–59% @ 250 nm 1
68–69% @ 600 nm
47–52% @ 800 nm
77% @ 1000 nm
79% @ 1400 nm
79% @ 1650 nm
Dark Count
~3 e – /hr/pixel (median, Aug
2010)
0.048 e – /s/pixel (median)
Readout Noise 3.1–3.2 e – 20.2–21.4 e – (pair of reads)
12.0 e – (16-read linear fit)
Full Well 2
63,000–72,000 e – 77,900 e – (mean saturation level)
Gain 1.55 e – /DN 2.28–2.47 e – /ADU
ADC Maximum 65,535 DN 65,535 DN
Operating Temperature −83°C 145 Κ
1. Quantum efficiency at 250 nm does not include multiple-electron events, which lead
to larger apparent efficiency in e.g., Figure 5.2.
2. The IR full well value is based on fully-integrated instrument ground testing. Other
CCD and IR parameters are derived from on-orbit data.
5.2 The WFC3 UVIS Channel CCD Detectors
5.2.1 Basics of CCD Operation
A charge-coupled device (CCD) is a silicon-based detector containing a
two-dimensional array of summing wells called pixels, short for pixel elements. Each
pixel accumulates electric charge in proportion to the number of photons striking that
location on the detector. Physically, the summing wells are created by electric fields
established at the depletion (charge-free) regions of the Si-SiO 2