The MODS detectors are e2v Technologies, Ltd CCD231-68 monolithic backside-illuminated 3072x8192 15-micron pixel CCDs operated by OSU MkIX detector controllers.

The Blue CCDs use standard 16-micron (100 Ohm-cm) silicon coated with the standard e2v astro-broadband coating for enhanced blue sensitivity.

The Red CCDs use 40-micron deep-depletion (>1500 Ohm-cm) silicon with the e2v Astro-ER1 coating for enhanced red sensitivity, providing QE of >50% at 900nm.

Basic Properties (-100C)

Manufacturer	e2v Technologies, Ltd., UK
Detector	CCD231-68
Format	3072x8192 pixels
Pixel Size	15 microns
Size	46.08x122.88mm
Pixel Full Well	400,000 e-
Maximum Output Signal1	200,000 e-
Responsivity	>8 uV/e-
Typical CTE	99.9995%
Amps	4 (quad readout)
Gain2	2.5 e-/ADU
Readout Noise2	<2.2 e- @ 40 kpix/s
	~2.8 e- @ 300 kpix/s
Linearity2	Blue: <1% at 55K ADU (16-bit ADC) Red: <1% at 55K ADU (16-bit ADC) Both correspond to ~120ke- at our typical conversion gains
Dark Current2	Blue: mean 1.0±0.2 e-/pix/hr Red: mean 1.2±0.1 e-/pix/hr
Typical Readout Times3	8Kx3K: 100s [grating spectroscopy] 4Kx3K: 75s [prism spectroscopy] 3Kx3K: 65s [direct imaging] 1Kx1K: 40s [center-slit acquisition]
Dewar Hold Times4	Blue: 32 hours Red: 30 hours
Red Line Spread Function	1.43 pixels (worst case)

Notes:

1. The "Maximum Output Signal" is the linearity limit of the high-responsivity output circuit (3V on the swing node).
2. Measured on-telescope in late 2010
3. Readout times are for unbinned pixels. Times for 2x2 binning should account for approx 35-40 seconds of irreducible overhead when attempting to scale by the square of the binning factor.
4. Measured in the instrument lab at 28°C and on-telescope at -2°C (ambient temperature).