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UVES Scientific CCD System
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The Red Scientific CCDs ( "STING" and "NIGEL" )

CCD Specifications

CCD alias name : STING NIGEL
Type : EEV CCD-44, backside illuminated, AR coated (single layer) MIT CCID-20, backside illuminated, AR coated
Number of pixels : [H] 2048, [V] 4102 [H] 2048, [V] 4102
Number of outputs : 2 2
Pixel size : 15 x 15 microns 15 x 15 microns

Cosmetic Defects of EEV CCD-44 ( "STING" )

Low Level Flat Field
Mean number of electrons per pixel » 4.000
Type of Defect : Location (x,y) : Number of pixels affected :
Single pixels Scattered over the CCD 1.450
Bias Image
0 sec. dark exposure, 985 pixels above 5 s
Type of Defect : Location (x,y) : Number of pixels affected :
Hot column - -
Long Exposure Dark Images
5 exposures of 1.800 sec. each, 572 pixels above 5 s
Type of Defect : Location (x,y) : Number of pixels affected :
Hot pixels trail 1580,1951 20
Hot pixels trail 1752,2156 50
Hot pixels trail 1908,2076 10
Hot pixels trail 1912,1682 10

Note : Pattern visible on the CCD surface like rests of evaporation from EEV.

Cosmetic Defects of MIT CCID-20 ( "NIGEL" )

Low Level Flat Field
Mean number of electrons per pixel » 4.000
Type of Defect : Location (x,y) : Number of pixels affected :
Hot column 63,2831 Up to the top
Trap 82,3227 10 pixels wide, to the top
Trap 937,2938 Up to the top
Trap 1605,827 Up to the top
Bias Image
0 sec. dark exposure, 1.520 pixels above 5 s
Type of Defect : Location (x,y) : Number of pixels affected :
Hot column 65,1 2 column up to the top
Hot column 1607,901 Up to the top
Long Exposure Dark Images
5 exposures of 3.600 sec. each, 2.432 pixels above 5 s
Type of Defect : Location (x,y) : Number of pixels affected :
Defect column 6,1 Whole column
Very hot pixels + trail 8,2692 » 200
Trap, 1 pixel wide, to the top 79,1223 y = 1223 to the top
Trap, 1 pixel wide, to the top 1548,803 y = 803 to the top
Trap, 1 pixel wide, to the top 881,2914 y = 2914 to the top
Trap, 10 pixels wide, to the top 31,3207 y = 3207 to the top

Note : Brick wall pattern strongly visible at short wavelengths.


Linearity

MIT CCD       EEV CCD
Linearity for the left output amplifier : + 0.20 / - 0.35 % 0 - 62.000 ADU       + 0.20 / - 0.35 % 0 - 62.000 ADU
Linearity for the right output amplifier :   + 0.18 / - 0.34 %   0 - 62.000 ADU       + 0.20 / - 0.35 %   0 - 62.000 ADU

Dark Current

MIT CCD :
Mean dark current < 1.1 ± 0.1 e-/pixel/hour @ - 120 °C.

EEV CCD :
Mean dark current < 1.0 ± 0.1 e-/pixel/hour @ - 120 °C.

Cosmic Ray Hit Event

MIT CCD :
Cosmic hit event rate : 1.67 ± 0.05 events/min/cm2.

EEV CCD :
Not measured.

Charge Transfer Efficiency

Vertical CTE Port A/B better than 0.999999 (6 - 9 s);
horizontal CTE Port A/B better than 0.999999 (6 - 9 s)

for all CCDs.

Bias Level

Adjusted to give around 200 ADU (dark frame).

Full Well

The 16 bit ADC gives 65.335 ADU full well to be multplied by the conversion factor for the readout mode. This will be the value in electrons.

Readout Direction

In dispersion direction.

Quantum Efficiency @ Temperature : -120 °C

(MIT/LL CCD "ZEUS" is the replacement for MIT/LL CCD "NIGEL" in July 1999)
EEV [STING] MIT [NIGEL]
Wavelength [nm] PRNU QE [%]
320 5 47.6
340 4 58.8
360 4 68.5
380 3 86.4
400 3 97.9
440 2 99.1
500 2 96.3
540 2 92.9
600 2 88.5
640 2 85.8
700 2 75.5
740 2 69.4
800 3 55.8
840 3 44.3
900 6 25.9
940 9 15.4
1000 15 4.6
1100 16 0.1
Wavelength [nm] PRNU QE [%]
320 7 13.3
340 7 9
360 7 6.8
380 9 10.8
400 6 24.1
440 3 45.6
500 2 68.8
540 2 79
600 2 88.1
640 2 90.8
700 2 86.8
740 2 81.2
800 3 65.4
840 2 54.3
900 3 30.8
940 5 20
1000 7 6.6
1100 14 0.1

Flat Field Images

The bandwidth of all full frames is 5 nm. Due to large QE differences in the U band, the two CCDs of the mosaic have been splitted.

Flat Field at 360 nm, EEV

Flat field of EEV at 360 nm.
Note the diamond pattern.		               Vertical cross section
Vertical cross section of the EEV frame at 360 nm.
Flat Field at 360 nm, MIT

Flat field of MIT at 360 nm.
Note the brickwall pattern.		               Vertical cross section
Vertical cross section of the MIT frame at 360 nm.
Flat Field at 650 nm

Flat field at 650 nm.
EEV is right, MIT is left.		                     
Flat Field at 900 nm

Flat field at 900 nm.
EEV is right, MIT is left.		               Horizontal cross section
Horizontal cross section of the frame at 900 nm.

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Last update: Jan 30, 2012
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