Mechanical design meeting, IAG, 31.03.2006
Calibration UnitCalibration Unitmechanical design mechanical design
Svend M. Bauer Svend M. Bauer Andreas Kelz, Andreas Kelz, Emil Popow,Emil Popow,
Martin M. RothMartin M. Roth
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CU Tech. CU Tech. RequirementsRequirements
for details see: ‚CU Technical Specifications‘ , Version: 2.3 from: 26/04/2005 VLT-SPE-MUS-14670-0022
- CU to replace and mimic VLT beam - CU to provide all light sources for flatfield and spectral calibration - CU to provide masks for image quality and geometrical calibration - CU to select between calibration and science beam - CU to be used for Narrow and Wide Field Mode - CU to meet environmental requirements
(e.g. stability, reliability, thermal emission, contamination, etc.)
Pre-assumptions: - CU is placed outside the rotator unit, i.e. is stationary- VLT focal plane not accessible to CU - VLT focal and pupil plane to remain unchanged by GALACSI and FO
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Reminder: Reminder: CU optical conceptCU optical concept
– A (large) integrating sphere for homogenous illumination (to simulate flatfield screen).
– One calibration relay lens (CRL) to mimic VLT beam (using a telescope objective).
- Precision masks at CU focal plane to calibrate instrument and to measure image quality.
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science beam
calibration beam
Integrating sphere
Lamps & electronics inside cabinets
Pick-up Element
Calibration Relay Lens
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CU size & locationCU size & location
– CU beam to be injected between GALACSI and FO at 240 mm behind VLT focal plane. NEW !
– VLT focal plane not accessible to CU. – Overall length from CPE to CIS: 3 meters– folding mirrors (not shown) neeeded to accommodate CU.
GALACSI ends: -500
VLT-focal plane:
0CU-beam:
+240FO-starts:
+320
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CU dimensionsCU dimensions
1.3 m
1.6 m
ca. 100 kg
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CU on platform: top CU on platform: top viewview
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CU on platform: side CU on platform: side viewview
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CU – outer partsCU – outer parts
Lamps and Proximity Electronicin individual housings
Flexible Light Guides to connect lamps to CU(3 meters max.)
Integrating Sphere forhomogenous illumionation
Stray light baffles
Calibration optics to mimic telescope
Folding mirror
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Calibration Mask Wheelon xyz-translation stage
Folding Mirror
common, aligned but removable platform
VLT focus
Calibration Pick-up Element
on x-translation stage
CU – inner partsCU – inner parts
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Calibration masksCalibration masks
MUSE pinhole mask: ~600 pinholes of 20 micron at 35x35 mm, MUSE trace mask: ~ 48 stripes of 0.123mm size precision and pitch tolerances: +/- 2 micron
Laser-manufactured (LMTB) mask: 1024 pinholes of 12 microns each at 1x1 mm
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B3110 Calibration Unit mechanical design
– No major risks identified with mechanical design
– Cost of Integrating Sphere: 10 kEuros – Cost of Precision Masks: 1 kEuro/piece
– Location of CU depending on final FO-platform
– CU estimated weight around 100 kg
– Removability of CU for GALACSI dismounting addressed
CU: SummaryCU: Summary