Integral Field Spectrograph Opto-mechanical concepts PIERRE KARST, JEAN-LUC GIMENEZ CPPM(CNRS),FRANCE

2 November 15 & 16, 2005 Pierre KARSTSummary  Requirements  General design  Opto-mechanical mount principle  References definition  Description of the units   Optical baffling studies  Cold test : preliminary lay out  Conclusion

3 November 15 & 16, 2005 Pierre KARST Requirements 1/2 Optical scheme : Beam geometry and active surfaces of the optical components = 350 to 1700 nm : Visible and IR detectors Respect of the alignment tolerance from 300 to 100 K Adjustment of the optical components and the detectors Optical components made of Zerodur (mirror) and BK7 (prism)

4 November 15 & 16, 2005 Pierre KARST Slicer unit Steering mirror unit Spectrograph unit Offner relay unit Detector unit Bench Requirements 2/2 Alignment tolerance GENERAL REQUIREMENT: COMPONENT  X =  Y=  Z= ± 0,1 mm Tilt Ox= Oy = ± 5 arcmin UNIT  X =  Y=  Z= ± 0,2 mm Tilt Ox= Oy = Oz = ± 5 arcmin  X =  Y=  Z= ± 0.02 mm

5 November 15 & 16, 2005 Pierre KARST Overview General design 1/5 Slicer unit Steering mirror unit Spectrograph unit Offner relay unit Detector unit Bench Support of the units Interface with external devices

6 November 15 & 16, 2005 Pierre KARST General design 2/5 Overall dimensions with the IR detector 630 mm 420 mm 210 mm

7 November 15 & 16, 2005 Pierre KARST General design 3/5 270 mm 160 mm 95 mm Slicer and spectrograph region (# SNAP spectro)

8 November 15 & 16, 2005 Pierre KARST General design 4/5 Visible test at room temperature Illumination module of the Proto 0 Demonstrator Optical table Support

9 November 15 & 16, 2005 Pierre KARST General design 5/5 InvarAluminiumTitaniumZerodurSiC CTE ( K)x Thermal 300 K (W/m/K) Specific heat (J/Kg/K) Young modulus (GPa) CostAAABC FabricationAAABC Choice material trade off: Compatibility with vaccum at low temperature (100 K) compatibility with Zerodur (Low CTE) Good alignment in the temperature range ( K) Good thermal properties high Young modulus Short allowed time = easy fabrication Low cost

10 November 15 & 16, 2005 Pierre KARST Opto-mechanical mount principle 1/6 Optical components : Rectangular mirror, Zerodur, 110x30x20 Cylindrical mirror, Zerodur,  26 to 34x10 Prism, BK7, mean thickness 10 mm, 26x26 Mount components : Frame and positioning parts, Invar. Clamping and screws : TBD Requirement in the range 300 to 100 K : Positioning tolerance : ± 0.1 mm ± 5 arcmin

11 November 15 & 16, 2005 Pierre KARST Opto-mechanical mount principle 2/6 Cylindrical mirrors : Plan contact with 3 points Centering with 2 small machined plans Mirror Elastic clamping Mirror mount Support

12 November 15 & 16, 2005 Pierre KARST Opto-mechanical mount principle 3/6 Rectangular mirror: Spring plungers Orientation Punctual contact Elastic clamps Plan contact Mirror

13 November 15 & 16, 2005 Pierre KARST Opto-mechanical mount principle 4/6 Mirror mount positioning: Stopper Spring plungers for the alignment Screws for fixation

14 November 15 & 16, 2005 Pierre KARST Opto-mechanical mount principle 5/6 Prism mount: 3 rotations are required. Positioning by 3 axis and screws on cantilever. 6 small pads 6 elastic clamps Prism

15 November 15 & 16, 2005 Pierre KARST Opto-mechanical mount principle 6/6 Prism mount: Position adjustment X Y Z X adjustment Z adjustment Y adjustment Centering of the axis < 10  m Accuracy of the angular adjustment < 3 arcmin  m screw Spring plunger

16 November 15 & 16, 2005 Pierre KARST References definition 1/2 Y Z O Y Z Y Z Y Z Y Z General reference: Active surface positions Origin = Slicer reference

17 November 15 & 16, 2005 Pierre KARST References definition 2/2 Accuracy of reference transfer with a CMM < 10  m  Positioning of the active surface < 40  m (Alignment tolerance = ± 0.1 mm) External surfaces Active surface Unit reference Positioning surfaces of the mirror Supporting surfaces of the mount Positioning and measurement of the actives surfaces respecting to the Unit reference

18 November 15 & 16, 2005 Pierre KARST Description of the units 1/8 Travel along the beam Slicer unit Steering mirror unit Spectrograph unit Offner relay unit Detector unit Bench

19 November 15 & 16, 2005 Pierre KARST Description of the units 2/8 Steering mirror support unit Steering mirror envelop Titanium support Pupil aperture Incoming beam Outgoing beam Z X Y Centering hole Locating hole Contact plan Shrinkage around the vertex of the mirror

20 November 15 & 16, 2005 Pierre KARST Description of the units 3/8 Slicer unit Z Y X Stack of slices Pupil mirrors Slit mirrors Incoming beam Outgoing beam

21 November 15 & 16, 2005 Pierre KARST Description of the units 4/8 Slicer unit Box and cover Made of Invar Mirror supporting blocks Made of Zerodur Mirror supporting blocks Made of Zerodur Pupil and slit mirror support Slice mirrors support The Zerodur assembly will be held by elastic clamps (TBD)

22 November 15 & 16, 2005 Pierre KARST Description of the units 5/8 Spectrograph unit Prism Camera mirror Collimator mirror Incoming beam Outgoing beam X Z Y Plan contact Orientation Stopper

23 November 15 & 16, 2005 Pierre KARST Description of the units 6/8 Offner relay unit Plan contact Orientation Stopper X Y Z Detector focal plan Offner primary mirror Offner secondary mirror Plane mirror Incoming beam

24 November 15 & 16, 2005 Pierre KARST Contact plan Fixation Description of the units 7/8 Visible detector Z X Y

25 November 15 & 16, 2005 Pierre KARST Description of the units 8/8 Bench Support of the unit Connection to the external devices Keeps the alignment specification (stiffness and thermal fluctuation) Contact plan Orientation Stopper Unit interface Cone Groove Flat

26 November 15 & 16, 2005 Pierre KARST Optical baffling studies

27 November 15 & 16, 2005 Pierre KARST Specific requirement: Vacuum < mbar Existing cryostat External illumination source unit: view port T° demonstrator < T° IR detector IR detector requirement: T° = 120 ± 5 K, stability 0.5 K Temperature fluctuation max < 1K/minute 1 short signal cable (20 cm) connected to a electrical board at room temperature Cold test: preliminary lay out 1/5 Diameter 180 mm 60 mm

28 November 15 & 16, 2005 Pierre KARST Cold test: preliminary lay out 2/5 Herschel cryostat View port Several available feedthroughs for the electrical output. Clean room It is equipped with two cryonegic heads

29 November 15 & 16, 2005 Pierre KARST Cold test: preliminary lay out 3/5 Overview Viewport Signal cable feedthrough Cryogenic devices

30 November 15 & 16, 2005 Pierre KARST Cold test: preliminary lay out 4/5 Overview avant le detecteur Signal cable Thermal baffling

31 November 15 & 16, 2005 Pierre KARST Cold test: preliminary lay out 5/5 IR detector on the demonstrator IR detector support Bench

32 November 15 & 16, 2005 Pierre KARSTConclusion This preliminary design meets the requirements Next steps, we have: - To finish the slicer unit concept - To detail the thermal studies - To define the optical baffling - To adapt the bench to the interfaces and thermal constraints

33 November 15 & 16, 2005 Pierre KARSTSpares Cut view of the mirror mount Alignment benches Herschel cryostat dimensions Mechanical description of the visible detector Slicer unit Shrinkage

34 November 15 & 16, 2005 Pierre KARST Alignment bench : spectrograph unit

35 November 15 & 16, 2005 Pierre KARST Alignment bench : Offner relay unit

36 November 15 & 16, 2005 Pierre KARST Cylindrical mirror mount

37 November 15 & 16, 2005 Pierre KARSTSpares Herschel cryostat : Dimensions

38 November 15 & 16, 2005 Pierre KARST Visible detector Mechanical description

39 November 15 & 16, 2005 Pierre KARST SLICER UNIT

40 November 15 & 16, 2005 Pierre KARST Tolerance for adjustment at room T° DescriptionDistance (mm) Shrinkage (mm) Required tolerance (mm) Tolerance for adjustment (mm) Slice mirror – pupil mirror ± (± 0.007) DescriptionDistance (mm) Shrinkage (mm) Required tolerance (mm) Tolerance for adjustment (mm) Spectro unit- Slicer unit ±0.2±0.16 Collimator - Prism ±0.1±0.036 Prism - Camera ±0.1±0.057 DescriptionDistance (mm) Shrinkage (mm) Required tolerance (mm) Tolerance for adjustment (mm) Spectro unit- Offner relay unit ±0.2±0.094 OPM - OSM ±0.1±0.068 DescriptionDistance (mm) Shrinkage (mm) Required tolerance (mm) Tolerance of adjustment (mm) Steering unit- Slicer unit ±0.2±0.12