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