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HIRDES UV Spectrographs Phase-B1-Study

HIRDES UV Spectrographs Phase-B1-Study @WIC Moscow June, 2006 N. Kappelmann.

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HIRDES UV Spectrographs Phase-B1-Study

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  1. HIRDES UV Spectrographs Phase-B1-Study @WIC Moscow June, 2006 N. Kappelmann

  2. History of the High Resolution Double Echelle Spectrograph: 1998 –2006 (WSO/UV): 2000 - 2001 HIRDES Phase – A - Study 2002 - 2004 Efforts to finance a Phase - A2 - Study (ns) 2005 - 2006 Phase - B1 - Study

  3. Design Criteria Phase A Wavelength Coverage : 103 – 320 nm Spectral Resolution : > 50.000 Simultaneous Coverage : as far as possible Possibility to Observe Bright Stars Improvement of FE of the MCP-Detector High Resolution Double Echelle Spectrograph (HIRDES) VUVES : 102.8 – 175.6 nm l/dl :55.000 UVES : 174.5 – 310.0 nm l/dl : 50.000 LSS : 102.8 – 310.0 nm l/dl : 320, spatial res: 1 - 2 arcsec

  4. B1-Study-Priority: Solving Interface Questions WSO/UV spacecraft interfaces, i.e. Optical Bench Plate, External Instrument Plate and Protective Case

  5. Work Share: Germany - Russia

  6. Design Criteria Phase B1 Wavelength Coverage : 103 – 310 nm Spectral Resolution : > 50.000 Simultaneous Coverage : as far as possible Possibility to Observe Bright Stars Improvement of FE of the MCP-Detector „Slit – Monitor“ Reduction of Mechanisms High Resolution Double Echelle Spectrograph (HIRDES) VUVES : 102.8 – 175.6 nm l/dl :55.000 UVES : 174.5 – 310.0 nm l/dl : 50.000

  7. Mechanical Layout: Three Independent Spectrographs Redundant Detectors Grey Filter Calibration Lamps UBV Detectors Tip/Tilt Mechanics

  8. UV Spectrograph - In Field Fine Guidance with Lens In field reflected at prism front surface towards focus mirror via lens onto fine guidance detector VUV Spectrograph - In Field Fine Guidance In field decoupled from 0th order reflection of grating via 2 mirrors onto fine guidance detector

  9. Spectrometer Arrangement LSS Spectrometer UV Spectrometer VUV Spectrometer

  10. Spectrometers with Housing Stand alone structure Independent assembly and alignment Attachment of common structure at optical bench (S/C)

  11. Trade OffActive Aluminum Structure vs. Thermostable Structure • Phase A Baseline • Thermally unstable Aluminum structure • 2 critical Focus Mechanisms ( Collimator Mirror , Echelle Grating) • Compensation of thermal gradients, temperature change, (drift) • Multi axes adjustment with very high accuracies required • Critical In Orbit Operation to find best focus position

  12. Trade Off: Thermomechanical Performance Maturity Costs Candidate Materials Aluminum Composite materials Ceramics • Thermostable CeSiC Structure • Required Spectral Resolution without Active Control of Optical Elements • Complex Collimator and Echelle Grating Mechanisms Skipped !!

  13. Spectrometers without Housing

  14. MCP Detector – Specification • Wavelength Range • UV 174.5 .. 310.0 nm • VUV 102.8 .. 175.6 nm • Total gain 107 e- / Photon • Pulse height distribution FWHM < 80% (TBC) • MCP pore diameter 6 µm (TBC) • Open area ratio (OAR) 80% • Length to diameter ratio • 80:1 (first and second single MCP) • 40:1 (third single MCP) • Active area 30x40 mm • Read out Method Wedge and Stripe Anode (WSA) • Photocathode material CsI, CsTe Depends on the wavelength range • Operational pressure < 1*10-5 mbar • Lifetime on ground (TBD)(after delivery) • Lifetime in Space 10 years (TBC)

  15. Isostatic Mirror Suspension(ORFEUS Heritage) Critical Components Design • Mirrors and Gratings • Quartz Glas with Invar flexural mounts • WFE: /20 at  = 633 nm • Surface Roughness: < 1 nm • Coatings: • UV : Al + SiO2 • VUV: Al + MgF2 • VIS: Al + SiO2 (Option: Au)

  16. Critical Components Design Isostatic Suspension made from CFRP (PACS heritage) Invar Suspension with SS flexural Blades (ORFEUS Heritage)

  17. Critical Components Design

  18. Vacuum Shutter – Mechanism Design • Functionality • Opening and closing of detector housing in vacuum • (Note: No window applicable due to optical performance) • Leakage Rate < 10-9 mbar • dm³ / sec • Design Principle (ORFEUS heritage) • Sliding crank for aperture cover • Kinematics • Travel Range 60 mm • Accuracy ± 50 µm (equiv. 20 arcsec) • Moving Mass << 1 kg (aperture cover) • Aperture 35 x 45 mm (MCP area + margin) • Mechanism motor drive and equipment • Spur Gear and Worm Gear • Stepper Motor (Phytron) • Mechanical end stops

  19. Servo Mirror – Mechanism Design • Functionality • Servo mirror steers main beam into redundant detector • Kinematics: • Translatoric movement of servo mirror (40 x 50 mm²) • Travel Range 60 mm • Accuracy ± 50 µm (equiv. 20 arcsec) • Moving Mass 100 g (mirror) • Mechanism motor drive and equipment • Spur Gear and Worm Gear • Stepper Motor (Phytron) • Mechanical end stops

  20. Result of redundancy concept trade-off Redundancy – System Concept

  21. Preliminary Test Matrix • Cross-switch function for HIRDES power supply and data interface to S/C • Common control unit for UVES and VUVES spectrometer • Cold redundancy • Switch over by relais command in case of failure occurrence (BB = breadboard, STM = Structural Thermal Mass Dummy, EQM = Engineering Qualification Model, PFM = Proto Flight Model, FS refurbished STM/EQM Model

  22. Preliminary Risk Assessment (top ranking risks)

  23. Technology Study Breadboard of New Electronic Concept Breadboard of a CeSiC Optical Bench Structure ORFEUS

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