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UVES Scientific CCD System
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Optomechanical Requirements for the CCDs for UVES

(see also the   Data for UVES Blue   before   the upgrade on 13/Oct/2004)
The flatness tolerances are still based on a maximum allowable defocus blur of 10 microns with a target of 5 microns (note that the optics will deliver 80 % of the energy within a circle of 15 - 20 microns).

The mosaicing tolerances for the red mosaic assume that independent calibration will be performed for the two segments and that the spectra will be merged only after full data reduction.

Blue Detector "PAVAROTTI" - EEV 2k x 4k Chip

Item Requirements Obtained Results
Optical field size 30.7 x 30.7 mm 30.7 x 30.7 mm
BFD
= The distance of the average CCD surface to the reference flange (mounting surface of field lens).		 4 mm + 0.25 - 0 -
Centering
= The distance between the optical center of the chip (not taking into accountpossible overscan pixels) and the mechanical axis of the dewar.		 < 0.5 mm -
P-V flatness
= The distance of the two planes, parallel to the reference flange, between which the sensitive surface of the chip or mosaic is contained. Applies to optical field size only.		 < 35 microns 15 microns
(room temperature)
Gap
= Width of optically inactive area between two chips of the mosaic. The gap runs parallel to the readout direction but in case of bad CTE, we have the option of rotating the detector by 90°. One full order is lost in the gap.		 N. A. N. A.
Pixel alignment
= Conformity of the real position of any pixel compared to a perfect global pixel raster. If necessary for automatic line identification, the misalignments may be mapped (determination of Dx, Dy, j). The mapping is stable with time to a fraction of a pixel.		 N. A. N. A.



Red Mosaic "STING" and "NIGEL" - EEV + MIT/LL, all 2k x 4k

Item Requirements Obtained Results
Optical field size 61.4 x 61.4 mm 61.4 x 61.4 mm
BFD
= The distance of the average CCD surface to the reference flange (mounting surface of field lens).		 4 mm + 0.25 - 0 -
Centering
= The distance between the optical center of the chip (not taking into accountpossible overscan pixels) and the mechanical axis of the dewar.		 < 0.5 mm -
P-V flatness
= The distance of the two planes, parallel to the reference flange, between which the sensitive surface of the chip or mosaic is contained. Applies to optical field size only.		 < 50 (25) microns 62 microns (cold)
Gap
= Width of optically inactive area between two chips of the mosaic. The gap runs parallel to the readout direction but in case of bad CTE, we have the option of rotating the detector by 90°. One full order is lost in the gap.		 < 1000 (800) microns 0.96 mm
Pixel alignment
= Conformity of the real position of any pixel compared to a perfect global pixel raster. If necessary for automatic line identification, the misalignments may be mapped (determination of Dx, Dy, j). The mapping is stable with time to a fraction of a pixel.		 < 150 (30) microns -

Flatness Measurements at room temperature     (BLUE SYSTEM)

Distance of the CCD from the field lens seat:
Required value: 9.125 ± 0.125 mm   (at room temperature)
Obtained value: 9.136 mm

Topography of "PAVAROTTI" with respect to the window backside at room temperature
(pv = 0.0150 mm)



Flatness Measurements at - 120 °C     (RED SYSTEM)

   rms       pv   
Analysis of the window back side    0.0021       0.0064   
Analysis of the chip    0.0064       0.0251   
Chip relative to the best fit plane of the window       0.0148       0.0626   

Topography of "NIGEL" and "STING" with respect to the window backside at - 120 °C
( pv = 0.0626 mm )
Topography of "NIGEL" and "STING" at - 120 °C
( pv = 0.0251 mm )

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