VIMOS Scientific CCD System

CCD Test Report "ROXANNE"

CCD Specification

CCD alias name :	ROXANNE
Type :	EEV 44-82, backside illuminated, single layer AR coated
Number of photosensitive pixels :	[H] 2048, [V] 4102
Number of outputs :	2
Pixel size :	15 x 15 microns
Overall rating :	Science

Readout Noise and Conversion Factor

	Readout Speed ( kps )	Readout Noise ( e^- rms )	Conversion factor ( e^- / ADU )
Port A ( left bottom )	350	3.8 ± 0.1	1.8 ± 0.1
Port B ( right bottom )	350	3.7 ± 0.1	1.8 ± 0.1

Quantum Efficiency

Wavelength [nm]	PRNU	QE [%]
320	1.8	55
340	1.8	62
360	1.8	67
380	1.3	78
400	1.0	87
450	0.9	89
500	0.9	88
550	0.9	85
600	0.9	82

Wavelength [nm]	PRNU	QE [%]
650	0.9	81
700	1.0	74
750	1.1	67
800	1.2	56
850	2.0	43
900	5.0	30
950	8.0	15
1000	10.3	5
1100	10.3	0

Cosmetic Defects

Low Level Flat Field Mean number of electrons per pixel » 4.500
Type of Defect :	Location (x,y) :	Number of pixels affected :
10 - 20 % QE loss (all wavelengths)	660 ® 880, 1 ® 1120	1.050 pixels scattered in many small 50 vertical pixels groups
20 % QE loss (all wavelengths)	186,261	Vertical direction, 70 pixels
20 % QE loss (all wavelengths)	758,3539	Vertical direction, 30 pixels
20 % QE loss (all wavelengths)	691,3598	Vertical direction, 30 pixels
20 % QE loss (all wavelengths)	207,3434	Vertical direction, 100 pixels
20 % QE loss (all wavelengths)	189,3455	Vertical direction, 100 pixels
20 % QE loss (all wavelengths)	y = 3748	Almost the whole row
Grand total amount of pixels outside main histogram : 4.600 less sensitive, 20 brighter.

Bias Image 0 sec. dark exposure, 25 pixels above 5 s, the perfect device
Type of Defect :	Location (x,y) :	Number of pixels affected :
Single pixel	1239,988	1
Single pixel	527,1067	1
Single pixel	306,175	1
...	...	...

Long Exposure Dark Images 6 exposures of 3.600 sec. each, 556 pixels above 5 s
Type of Defect :	Location (x,y) :	Number of pixels affected :
Hot pixels aligned in y-direction	306,93	150
Hot pixels aligned in x-direction	2071,166	20
Hot pixels aligned in x-direction	480,2438	20
Hot pixels aligned in x-direction	151,2518	20
Hot pixels aligned in y-direction	398,124	100

Notes : This device has some pixels with a loss of QE (like a neutral filter above the pixels), their behaviour is really linear and can be flat field out very well. Apart from that this is the best EEV 44 device ever tested at ODT. ODR/L voltage should be less than 21.5 V to avoid amplifier glowing.

Images

All images got the serial register at the bottom of the image. All are full frames images including 50 pixels of X-pre-/overscan and 100 pixels of Y-overscan.

All images are full frames (1 CCD pixel = 1 screen pixel) otherwise mentionned.

Bias frame

Dark frame (5 median stacked 1 hour exposure dark frames)

Cosmetics, flats fields from 60 cm diameter integrating sphere.

340nm, 4nm bandwidth

600 nm, 4nm bandwidth

900 nm, 4nm bandwidth

Linearity

	Speed ( kps )	Non-Linearity		Range ( ADU )	Saturation level ( e^- )
		Peak - Peak ( % )	Rms ( % )
Port A ( left bottom )	350	0.42 / - 0.67	0.31	0 - 65535	117 K
Port B ( right bottom )		0.33 / - 0.42	0.17

Linearity Curve of Left Port (350 kps)

Linearity Curve of Right Port (350 kps)

Dark Current

Mean dark current 1.0 ± 0.4 e^-/pixel/hour @ - 120 °C.
Exposure time used in frames : 6 exposures of 3.600 sec. each.

Notes : Ultra clean chip, very few bright pixels.
It takes 4 hours after a flat field to get this dark current figure, otherwise remanence effects leading to higher dark current figure will occur.

Cosmic Ray Hit Event

Cosmic hit event rate :

22.9 ± 0.4 events/min/CCD;
1.14 ± 0.02 events/min/cm².

Charge Transfer Efficiency

Vertical CTE to port A/B : 0.9999998 (almost seven 9 s);
horizontal CTE to port A/B : 0.9999991 (six 9 s).

Measurement Conditions

Prescan :

[H] 50, [V] 0

Overscan :

[H] 50, [V] 70

Temperature :

- 120 °C

Bias Voltages (V) :

	Port A (left bottom)	Port B (right bottom)
RD	11.0	11.0
OD	21.0	21.0
JD	25.0	25.0
IF	- 8 ® + 2	-

Gain (Port A, B) :

Stage 1 = 2.25,
Stage 2 = 5.0

General Comments :

No error bars available for QE measurements, rms error in red is about 1 %, green 2 % and blue 3 - 4 %.
This device has a very low f_cho = 8 V instead of 11 V. It implies the Reset Drain, Output Drain to be lowered.

Report Date :

25/July/1999

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