Dorado: ESO CCD Test report

EEV 44-82 -1-A57
CCD name : Dorado
Serial number : 00152-16-01
Type : Backside, Single layer AR Pixel size 15x15 µm
Number of photosensitive pixels 2048 x 4102 [HxV]
Number of outputs : 2
Overall rating :

Measurement made by the: 2001
Data reduced by Fabrice Christen the: 4 September 2001

Quantum Efficiency, PRNU



Wav.

Qe Dorado

Error

PRNU RMS (%)

Phase

320

48.4

1.4

3.2

7.22

330

53.8

1.6

3

7.16

340

57.1

1.1

2.93

7.13

350

58.4

0.57

2.91

7.13

360

60.5

0.6

2.93

7.13

370

64.6

0.64

2.72

7.06

380

72.7

0.72

2.27

6.88

390

80.3

0.82

2.02

6.76

400

83.8

0.85

1.91

6.7

420

87

0.88

1.82

6.66

440

88.4

0.89

1.79

6.64

450

88.2

0.89

0

6.64

460

88

0.88

1.78

6.63

480

87.2

0.88

1.78

6.63

500

87.2

0.87

1.78

6.63

520

86.9

0.87

1.78

6.64

540

85.9

0.86

1.8

6.64

550

85.2

0.85

0

6.65

560

84.5

0.84

1.83

6.66

580

84.3

0.84

1.86

6.68

600

82.8

0.82

1.92

6.71

620

81.9

0.81

1.99

6.75

640

80.6

0.78

2.07

6.78

650

79.6

0.77

0

6.8

660

78.6

0.76

2.14

6.82

680

76.7

0.73

2.22

6.85

700

73.6

0.69

2.38

6.92

720

70.5

0.65

2.53

6.99

740

66.7

0.61

2.7

7.05

750

64.5

0.59

0

7.07

760

62.2

0.56

2.82

7.09

780

57.8

0.51

2.86

7.11

800

53.3

0.4

2.9

7.13

820

48.7

0.41

2.93

7.13

840

44.4

0.37

2.69

7.05

850

42.2

0.35

0

7.09

860

39.9

0.33

2.9

7.13

880

35

0.28

3.32

7.26

900

29.3

0.24

4.03

7.45

920

23.6

0.18

5.55

7.76

940

17.9

0.14

7.2

7.97

950

15.3

0.12

0

8.03

960

12.6

0.1

8.02

8.08

980

8.4

0.06

9.28

8.22

1000

4.9

0.04

9.88

8.28

1040

0.93

0.01

11.7

8.29

1100

0.13

0

35.3

8.69



Table 1: Measurement of the Quantum Efficiency.

Quantum efficiency, comparison

In this section you can compare the QE we measured with the testbench and:

Figure 1: Comparison between the QE measured by ESO, the QE measured by Marconi, ESO specification and minimum specification.

Figure 2: Ratio between the ESO measurements and the ESO minimum specification.


Quantum efficiency, special specification



Special specification

Wavelength(nm)

Minimum spec. (%)

ESO measurements (%)

Result

350

50

58.4

OK

400

80

83.8

OK

650

80

79.6

Under the minimum spec.

900

25

29.3

OK

Conclusion:

No, this CCD is not in the 25 %



Table 2: Minimum specification for 25 % of the CCDs.

Difference between QE measurements made by ESO and Marconi.



Comparison QE ESO and QE Marconi

Wavelength (nm)

QE ESO (%)

Qe Marconi (%)

Difference (Eso - Marc. %)

Relative difference (Marconi as reference %)

Ratio QE ESO / QE Marconi

350

58.4

50.6

7.8

15.4

1.15

400

83.8

87

-3.2

-3.7

0.96

500

87.2

94.6

-7.4

-7.8

0.92

650

79.6

85.5

-5.9

-6.9

0.93

900

29.3

29.5

-0.2

-0.7

0.99



Table 3: Difference and relative difference between ESO measurements and Marconi.

Figure 3: Graphic representation of the difference and the relative difference.

Figure 4: Ratio between the ESO measurements and the Marconi measurements


PRNU

In this section you can compare the PRNU we measured at ESO and:

Figure 5: Comparison between the PRNU measured by ESO, the PRNU measured by Marconi, and the maximum specification.

Figure 6: Ratio between the ESO measurements and the Maximum specification.

Figure 7: Graphic representation of the difference and the relative difference.

Figure 8: Ratio between the ESO measurements and the Marconi measurements.





Comparison QE ESO and QE Marconi

Wavelength (nm)

PRNU ESO (rms %)

Maximum spec.

PRNU Marconi

Difference (ESO – Marc.)

Relative difference (Marc. as reference)

Ratio PRNU ESO / PRNU Marconi

320

3.2

6

0

0

0

0

350

2.91

5

3.3

-0.39

-11.82

0.88

400

1.91

2.5

1.2

0.71

59.17

1.59

500

1.78

2

0.9

0.88

97.78

1.98



Table 4: Difference and relative difference between ESO measurements and Marconi.

Comparison with the contract

In this section you will see the if the values we have measured for the QE and the PRNU are in accordance with the contract.



Wavelength (nm)

Qe

PRNU

320

OK

OK

340

OK


350

OK

OK

360

OK


380

OK


400

OK

OK

450

OK

OK

500

OK

OK

550

OK


600

OK


650

OK


700

OK


750

OK


800

OK


850

OK


900

OK


950

OK


1000

Below the specification




Table 5: Comparison between the values we have measured and the specifications in the contract.

Cosmetic

flat field

For the flat field we use three wavelengths, 350 nm, 600 nm and 900 nm. For each wavelength we make two images, high level (45000 ADU) and low level (1000 ADU).

350nm (UV), bandwidth 5nm

600nm, bandwidth 5nm

900nm, bandwidth 5nm

High level
Low level
High level
Low level
High level
Low level

Table 6: Flat field for three wavelengths.

Bias and dark

The time exposure, for the long dark exposure, is 3600 seconds.

Bias

Long exposure dark image

Table 7: Bias and dark.

Remark: As you can see on the dark image we have on this CCD some electroluminescence (two white spots below).

Readout noise/Conversion factor

Clock mode: 225kpx/rr/HG/512
CCD Dorado, right port
Conversion Factor=   0.53085e-/ADU ±0.001825     for 20491.2ADU                                                                  
RMS noise        =   3.9575e-      ±0.1876                                                                                       

CCD Dorado, left port
Conversion Factor=   0.51719e-/ADU ±0.002056     for 20425.3ADU                                                                  
RMS noise        =   3.4704e-      ±0.17                                                                                         


Clock mode: 50kpx/rlrl/HG/512
CCD Dorado, left port
Conversion Factor=   0.50531e-/ADU ±0.001956     for 19851.6ADU                                                                  
RMS noise        =   2.7981e-      ±0.1402                                                                                       

CCD Dorado, right port
Conversion Factor=   0.51431e-/ADU ±0.002722     for 19679.4ADU                                                                  
RMS noise        =   3.3139e-      ±0.4088

Linearity (TDI method)

RMS non linearity (%)         = 0.23
Peak to peak non linearity (%)= 0.68



Figure 9: Error of linearity

Figure 10: Residual non linearity.

Dark current

Exposure time (s) = 3600
Dark current : 1.67 ± 0.05 ADU/hour/pixel
Dark current : 0.94 ± 0.03 e-/hour/pixel

Charge Transfer Efficiency (CTE) Not available

Low level (Around 2500 ADU)
Horizontal CTE = 
Vertical CTE   = 

High level (Around 25000 ADU)
Horizontal CTE = 
Vertical CTE   =

Cosmetic defects

In this section we expose the hot pixel, the dark pixel, the trap and the very large trap we found.

Hot pixel

A hot pixel provides a signal of > 60 e- / pixel / hour.


Result: 48 hot points.

Very bright pixel

a very bright pixel provides a signal of > 200000 e-/pixel/hour


Result: 0 very bright pixel.

Dark pixel

A dark pixel is one with 50% or less than the average output for uniform intensity light level, measured with a flat field level around 500 photo-electrons.


Result: 0 dark pixels detected.

Trap

A trap is defined as a pixel that captures more than 10 electrons, measured with a flat field level around 500 photo-electrons.


Result: 3 trap

Very large trap

A very large trap is defined as a pixel that captures more than 10 000 electrons, measured with a flat field level around 90% of full well capability.


Result: 16 very large trap.


Remark: These 16 points are gathered into two groups like on this image:


Bad column

A bad column is 10 or more contiguous hot or dark pixels in a single column or a very bright pixel or a very large trap.


Result: 1 bad columns.

Conclusion

Here is a summary of cosmetic defects:

Hot pixel

Dark pixel

A very bright pixel (a)

Trap

Very large trap (b)

Sup. 10 contiguous pixels (c)

Total bad column (a+b+c)

ESO

48

0

0

3

16

0

16

Marconi

64

11

1

0

0

11

Table 8: Summary of cosmetic defects.

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