nirspec ifu eric prieto final presentation definition phase may, 11th – estec

NIRSpec IFUNIRSpec IFU

Eric PrietoEric Prieto

Final Presentation Definition PhaseFinal Presentation Definition PhaseMay, 11th – ESTECMay, 11th – ESTEC

May, 11th 2004May, 11th 2004 Nirspec Definition phase Final PresentationNirspec Definition phase Final PresentationESTECESTEC

22

IntroductionIntroduction

Requirements overviewRequirements overview ImplementationImplementation PerformancePerformance BudgetsBudgets ComplianceCompliance StatusStatus


33

Slicer PrincipleSlicer Principle

1. Field divided by

slicing mirrors in

subfields

2. Telescope pupil on

the pupil mirrors

3. Aligned pupil

mirrors

4. Subfields imaged

along an entrance

slit

Field beforeslicing

Pseudo-slit

Slicing mirror (S1)

Spectrogram

Pupil mirrors(S2)

To spectrograph

Field optics (slit mirrors S3)

From telescopeand fore-optics

1

2

3

4

How to rearrange 2D field to enter spectrograph slit:

Courtesy: JR Allington-Smith


44

Requirement overviewRequirement overview

FOV: 3”x3” @ 0.075” FOV: 3”x3” @ 0.075” (40 slices of 40 pixels)(40 slices of 40 pixels) R~3000 R~3000 (Slit mode gratings)(Slit mode gratings) Optical throughput > 50%Optical throughput > 50% Mass < 1kgMass < 1kg


55

ImplementationImplementation

No dedicated selection mechanismNo dedicated selection mechanism A 3mm aperture in the MSA frameA 3mm aperture in the MSA frame MSA magnet hides the IFU aperture during MOS operationMSA magnet hides the IFU aperture during MOS operation


66

ImplementationImplementation

Slicer Stack(40 slices)

IFU aperturePupil mirror Line(40 elements)

Slit mirror Line(40 elements)

Relay optics


77

Slicer stack subassemblySlicer stack subassembly


88

Lines subassembliesLines subassemblies

Opto-mecha mount: clamps on stiff Opto-mecha mount: clamps on stiff

Zerodur barZerodur bar

Titanium clampsTitanium clamps

Positioning reference: thrustPositioning reference: thrust

Each individual mirrors optically Each individual mirrors optically bonded on the barbonded on the bar

Bonding strength: see slide 14Bonding strength: see slide 14


99

Optical performance and budgetOptical performance and budget

Item Design Manufacturing Assembly Quad sum

Fore optics (2 mirrors) 65 nm 30 nm 10 nm 72 nm

Slicer (3 mirrors) 26 nm 35 nm 10 nm 45 nm

Folding mirrors (4 mirrors) 0 nm 40 nm 0 nm 40 nm

Spectrograph coupling 1mm of defocus in MSA plane: 20 nm 20 nm

Total WFE 96 nm

System Margin 49 nm

Overall Budget WFE 108 nm

Relay optics

Slicer Unit

Prototype

Throughput reflectivity: > 83% (R123: with 25% of margin)

Throughput diffraction: > 90% (equivalent to R76)

Overall IFU: 75%

Overall NIRSPEC+IFU: 30% (diffraction included)


1010

Mass BudgetMass Budget

Item Current design mass System margin Mass

Mechanics 510 300 810

Baffling 150 100 250

Optics 70 70 140

Thermal sensor 4 x 3g= 12g 0 12

Total 1212 g


1111

ComplianceCompliance

No major issue to be compliantNo major issue to be compliant Only vibration compliance to be demonstrated (in July 2004)Only vibration compliance to be demonstrated (in July 2004) Compliance to optical interfaceCompliance to optical interface Compliance with allocated volumeCompliance with allocated volume To Be Finalized: Mechanical interface with structureTo Be Finalized: Mechanical interface with structure

ItemItem RequirementRequirement PerformancePerformance MarginMargin

FOVFOV 3”x3”3”x3” 3”x3”3”x3” by designby design

SamplingSampling 0.075 +/-2.5%0.075 +/-2.5% 0.0750.075 by designby design

WFEWFE 108 nm108 nm 96 nm96 nm 49 nm49 nm

ThroughputThroughput 60%60% 83%83% 25%25%

MassMass 1kg1kg 1.212kg1.212kg470g of margin470g of margin

--212g212g

In the system marginIn the system margin


1212

DDV plansDDV plans

Item Deliverable Date

Structural Thermal Model 19/04/06

EQM 01/08/06

FM 21/09/07

SM 31/12/07


1313

Status: Prototype performancesStatus: Prototype performances

Thermal straps

Thermometers


1414

Status: Optical bonding strengthStatus: Optical bonding strength

Bonding surface: 47mm²Bonding surface: 47mm² Load increase speed: 4 N/minuteLoad increase speed: 4 N/minute 3 tests @ 18N3 tests @ 18N Mass: 0.36g Mass: 0.36g Equivalent acceleration: Equivalent acceleration: 5000 G Factor 100 of margin5000 G Factor 100 of margin

Lessons Learned:

Perpendicular Bonding

TO BE AVOIDED

Optical bonding

Optical bonding


1515

Conclusion: MaturityConclusion: Maturity Manufacturing maturity:Manufacturing maturity:

Slicer: okSlicer: ok Pupil/slit line: okPupil/slit line: ok Structure/opto-mechanical mount: okStructure/opto-mechanical mount: ok

Cryo maturity:Cryo maturity: Slicer: okSlicer: ok Pupil/slit line: okPupil/slit line: ok Structure/opto-mechanical mount: okStructure/opto-mechanical mount: ok

Vibration maturity: July 2004Vibration maturity: July 2004

Optical performance maturity:Optical performance maturity: Slicer: okSlicer: ok Pupil/slit : okPupil/slit : ok Overall system: ok (@30-40°K and RT)Overall system: ok (@30-40°K and RT)


1616

Conclusion: Conclusion:

Very close to be a mature technologyVery close to be a mature technology It is an unique opportunityIt is an unique opportunity It is very efficient It is very efficient (No slit losses)(No slit losses)

Most of ground instruments for 2010 in the European Most of ground instruments for 2010 in the European (the World?) community have IFU capabilities in the (the World?) community have IFU capabilities in the VIS/NIR Domain: VIS/NIR Domain:

(as GNIRS/GEMINI, KMOS/VLT, MUSE/VLT, Planet Finder/VLT, …)(as GNIRS/GEMINI, KMOS/VLT, MUSE/VLT, Planet Finder/VLT, …)

NIRSpec?NIRSpec?

nirspec ifu eric prieto final presentation definition phase may, 11th – estec

Documents

optical performance

overall nirspec ifu

okpupilslit line

maturitymanufacturing

okcryo maturity

okvibration maturity

optical interfacecompliance

r76overall ifu