Fornax: ESO CCD Test report

EEV 44-82 -1-A57
CCD name : Fornax
Serial number : 00152-13-02
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: 27 June 2001 – 11 July 2001
Data reduced by Fabrice Christen the: October 31st, 2001

Quantum Efficiency, PRNU

Measure realized at -120 deg.

Wav.

Qe Fornax

Error

PRNU RMS (%)

Phase

320

49.4

1.4

3.47

7.41

330

55.1

1.6

3.25

7.34

340

58.8

1.1

3.16

7.31

350

60.6

0.59

3.16

7.31

360

63.1

0.62

3.14

7.31

370

67.3

0.66

2.85

7.21

380

75.1

0.74

2.19

6.94

390

82.3

0.85

1.79

6.73

400

86.3

0.87

1.59

6.61

420

89.3

0.9

1.43

6.5

440

90.7

0.91

1.38

6.46

450

90.45

0.91

0

6.45

460

90.2

0.91

1.36

6.44

480

89.8

0.9

1.35

6.43

500

90.3

0.91

1.34

6.43

520

90.3

0.91

1.33

6.43

540

89.6

0.9

1.34

6.43

550

89

0.89

0

6.44

560

88.4

0.88

1.34

6.44

580

88.1

0.88

1.36

6.45

600

86.8

0.86

1.38

6.47

620

85.7

0.84

1.41

6.5

640

84.3

0.82

1.45

6.53

650

83.2

0.81

0

6.54

660

82.1

0.8

1.49

6.56

680

79.9

0.76

1.52

6.58

700

76.6

0.72

1.64

6.66

720

73.4

0.67

1.86

6.79

740

69.7

0.63

1.94

6.83

750

67.35

0.61

0

6.88

760

65

0.58

2.15

6.93

780

60.3

0.53

2.15

6.93

800

55.1

0.48

2.2

6.96

820

50.5

0.43

2.16

6.94

840

45.9

0.39

2

6.85

850

43.5

0.37

0

6.92

860

41.1

0.34

2.27

6.99

880

35.9

0.29

2.63

7.13

900

30.2

0.24

3.24

7.34

920

24.2

0.19

4.9

7.74

940

18.5

0.14

6.2

7.92

950

15.75

0.12

0

8.01

960

13

0.1

7.48

8.11

980

8.36

0.06

8.88

8.29

1000

5.01

0.04

9.92

8.35

1040

0.92

0.01

9.02

8.29

1100

0.13

0

8.98

8.35

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

60.6

OK

400

80

86.3

OK

650

80

83.2

OK

900

25

30.2

OK

Conclusion:

Ok, this CCD is 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

60.6

51.1

9.5

18.6

1.19

400

86.3

85

1.3

1.5

1.02

500

90.3

89

1.3

1.5

1.01

650

83.2

80.5

2.7

3.4

1.03

900

30.2

28.8

1.4

4.9

1.05



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

3.47

6

0

0

0

0

350

3.16

5

4.8

-1.64

-34.17

0.66

400

1.59

2.5

1.6

-0.01

-0.62

0.99

500

1.34

2

1

0.34

34

1.34



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

OK




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).

350 nm (UV), bandwidth 5 nm

600 nm, bandwidth 5 nm

900 nm, bandwidth 5 nm

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 Fornax, right port
Conversion Factor=   0.52794e-/ADU ±0.001899     for 20644.5ADU                                                                  
RMS noise        =   3.309e-       ±0.1579                                                                                       

CCD Fornax, left port
Conversion Factor=   0.54125e-/ADU ±0.002398     for 20050.3ADU                                                                  
RMS noise        =   3.4281e-      ±0.1591 


Clock mode: 50kpx/rlrl/HG/512
CCD Fornax, left port
Conversion Factor=   0.5235e-/ADU  ±0.001772     for 20344.2ADU                                                                  
RMS noise        =   2.8653e-      ±0.1381                                                                                       

CCD Fornax, right port
Conversion Factor=   0.50892e-/ADU ±0.001891     for 20731.9ADU                                                                  
RMS noise        =   2.8974e-      ±0.1441

Linearity (TDI method)

RMS non linearity (%)         = 0.27
Peak to peak non linearity (%)= 0.78



Figure 9: Error of linearity

Figure 10: Residual non linearity.

Dark current

Exposure time (s) = 3600, Temperature = -120 C

Dark current : 1.54 ± 0.07 ADU/hour/pixel
Dark current : 0.86 ± 0.04 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: 335 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: 23 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: 14 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: 1 very large trap.


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: 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

335

23

0

14

1

1

3

Marconi

158

11

7

1

0

12

Table 8: Summary of cosmetic defects.


Remark: This CCD has not a clean surface and it is difficult to determine the cosmetic defects.

Back to the overview page ESO Test Reports for the OmegaCAM CCDs