1. Integral Field Spectrograph Anne EALET CNRS (IN2P3) FRANCE, Instrument Scientist Eric PRIETO CNRS,INSU,France,Project Manager 11 November 2003

2. 2 Spectrograph: Background SNAP imager spectro magnitude A contribution supported by CNRS (IN2P3 & INSU) and the French space agency (CNES) No exchange funding, non US cost  M,   ID Ia See overview in S.Perlmutter/M.Levi talks

3. 3 Spectrograph: Overview Spectrograph studies Science driver Requirements for the Spectrograph Spectrograph concept and Status Risk analysis R&D French activities: Slicer prototype Detector and electronics R&D plan Summary

4. 4Specifications A spectrograph dedicated for SN physics —Identification of SNIa Si 6150 A line up to z=1.7 (range) —Precision on physical parameters to correct magnitude (resolution) and derive systematics for evolution — can measure the host galaxy redshift when possible —Precise calibration (sampling)

5. 5Requirements An instrument minimizing exposure time for faint SN Wavelength range [0.35-1.7]  m Spatial resolution 0.15” Low spectral resolution (~100) Under sampled in the NIR to minimize the noise (+dithering to recover) Two arms to increase performance to improve UV part of the faint SN Highest throughput by reflective optic only (mainly limitated by detector QE) +

6. 6 Spectrograph characteristics Property VisibleIR Wavelength coverage (  m) 0.35-0.980.98-1.70 Field of view 3.0"  6.0" Spectral resolution,  70-20070-100 Spatial resolution element (arc sec)0.15 detectors LBL CCD 10  m HgCdTe 18  m Efficiency with OTA and QE>40%

7. 7 Spectrograph concept

8. 8 Spectrograph: Design constraints REQUIREMENTS for space: Compactness Reflective optics No accurate slit positioning All information in one exposure High throughput 3D spectroscopy for galaxy +SN X (pixel) INTEGRAL FIELD TECHNOLOGY: reconstruct a DATA CUBE 3D (x,y, ) image of the sky use a technique to rearrange the 2D (x,y) in a 1D equivalent long slit => sliced the field Y(slice) Trade-off

9. 9CONCEPT 3D spectroscopy with integral field technology: Integral Field using the new generation of Image Slicer Disperser=Prism for low and “constant” resolution 2 detectors (CCD, HgCdTe) Dichroic for beam separation All spectral and spatial information in one exposure Fulfills all requirements for science and space

10. 10 Spectrograph: Functional Overview Science Software Relay Optics Slicer Unit Collimator Prisms Dichroics NIR CAM VIS CAM NIR Focal plane Visible Focal plane Shutter Dithering Thermal control Interface Electronics Calibration lamps Operation

11. 11 Spectrograph design status

12. 12 Instrument design road map Primary SNAP specifications Concept definition Pre conceptual design Detailed simulation New requirements Conceptual design Define system requirements Prove the feasibility Verify performances Budget errors 2002 2003 First requirements Interface control document R&D SLICER AND DETECTORS/ ELECTRONIC

13. 13 optics with 7 mirrors two arms configuration Two prisms Pre optical design Visible detector IR detector slicerprisms entrance

14. 14 Spectrograph: implementation Under the global shielding

15. 15 Global shielding + local shielding around detector (focal plan) Thermal study (LBNL) T > 100 K Opto-mechanical concept First studies on Mechanical environment Thermal analysis Modal analysis interface with SNAP Dimension < 400 mm Weight < 15 Kg Material Invar Kinetical mount Details in E.Prieto talk

16. 16 Focal plan development Mechanical/thermal/interface studies to define a preliminary design No ‘single point failure’ => Detectors should to be duplicated: two detectors and their electronic: Field of view of 3’’X6‘’ instead of 3’’X3’’ Need 40 slices No effect on optic

17. 17 Spectrograph issues Focal plane: Visible detector : very low noise versus cosmic ray radiation lower integration time because of radiation => larger readout noise alternatives: LBL CCD issue thinner (CRIC: noise ok ) EEV CCD issue fringing HYVISI issue dark current (same readout elec than IR) IR Detector : 3000s integration / cosmic rays rejection (noise and drift) Rational: reduce spectro allocated time of at least 2 or 3!

18. 18 Instrument simulation Physics specifications Hardware specifications Optical design Optical simulation Optomechanical simulation and design Final performances Library of PSF Pixels response Physics simulation Calibration Construct prototype OK AND Yes No

19. 19 Simulation status A full detailed simulation of the optical design is under developement Used to simulate SN spectrum on the whole wavelength range Used to verify the basic performances of the instrument (resolution and throughput) New developments are going to parameterize PSF using HERMIT polynomial decomposition Implementation of realistic data cube will be possible within the SNAP software Volume of data will be kept small with reasonable CPU time Background NeNe #pixels Background subtracted Calibrated Exemple of a spectrum at z=1.7

20. 20 Calibration status First calibration oriented performance requirement done (doc) Major calibration procedures have been identified : flatfielding wavelength absolute spectro-photometric calibration Preliminary list of needs for calibration have been identified The strategy will be developed next year : Details on procedure and error budget evaluation Derive stability requirements and observatory Used as input to the operation time budget

21. 21 instrument roadmap instrument roadmap l Scientific and technical requirement l Optics  Optical development: new design, tolerance studies  Dichroic studies and prototyping (first expertise dec 03)  Structural :Trade on the structure, choice,opto-mechanical studies  Thermal :modal and thermo-elastic analysis l Focal Plane  Review of detectors/technologies –choice  Early focal plane development l Slicer  Slicer technology pushed to TRL 6  adaptation to SNAP l Calibration procedures studies l Software development : data processing/monitoring l Interface control requirement

22. 22 R&D: Risk analysis riskmitigationactivitycompletion Slicer development ESA/NGST prototype30 elmts in space environment TRL6 end 2003 Snap adaptation 2005 Focal planeDetector technology trade-off Early focal plane development R&D on detector and readout electronic Detector choice and Concept Design 2005

23. 23 R&D activities

24. 24 Slicer development and validation to TRL6 level (ESA funding) —Prototype ready at LAM —Test on visible and IR —First test results (see eric talk) Ongoing R&D slicer

25. 25 Slicer results alignment of the virtual slits on the slit mirrors within 20µm See E.Prieto presentation Impressive alignment of the pupils on the pupil mirrors within 50µm

26. 26 R&D detectors/electronic Detector validation and electronic development (IN2P3 funding) CCD Detectors: Test of CCD from LBNL (frame transfer, performance, QE, readout) in progress Evaluation of a CCD with EEV as spare with emphasis fringing test and efficiency. Issue on radiation : test for 2005 if funded Bench test ready Electronic: readout evaluation using MEGACAM-like-ASIC for low noise purpose

27. 27 R&D detectors/electronic IR Detectors: MUX received Prototype ordering HgCdTe 1kx1k cut off at 1.7  m for evaluation (temperature, QE, dark, readout…) to be received Jan 04, test result June 04 Bench test be ready for Jan 04 Electronic: readout demonstrator for IR pixels. FPGA + microprocessor + Ethernet Delivered june 04

28. 28 Spectrograph: R&D deliverables DeliverableCompletionStatus Trade & decision slicer technology-TRL5Mar-01done Baseline specificationsJul-02done Performance requirementsNov-03draft Science and technical trade studiesNov-03draft Pre-conceptual designNov-03done Interface control requirement with SNAPNov-03draft Calibration procedures studiesDec-03draft Slicer prototype report –TRL6May- 04 Review on detector/ decisionSep-04 Detector confirmationDec-04 Instrument concept/ZDRDec-04 Focal plane development planJul-05 SNAP Slicer prototype developmentJul-05 Interface control requirement with SNAPJul-05 Conceptual design report/reviewJan-06

29. 29 Spectrograph: R&D Manpower Team Activity FTE Associated spectro FY04/05 INSU/CNRS+ European team Generic slicer for space application 10 2.5 IN2P3/INSU/CNRS + Euro 3D Software for 3D spectrograph 102 R&D effort within the SNAP collaboration and outside the collaboration Sharing development when possible

30. 30 PersonnelActivity FTE FY04 FY05 Dr.A.EaletInstrument Scientist 0.8 Mr.E.PrietoP.Manager/Optic lead 0.5 Mr C.MacaireSlicer/optical engineering 0.5 TBCOptical engineering 0.20.5 Mr.P.E.BlancMecha. /thermal lead 0.5 Mr.C.RossinThermal designer 0.20.3 Mr.P.LevacherElectronic control engineering 0.2 Dr.A.BonissentSoftware lead 0.8 Dr.A.TilquinSimulation 0.5 Dr.P.FerruitCalibration 0.20.5 M.AumeunierPHD/simulation/optic 1. R&D Manpower Spectrograph design (in2p3/insu) R&D Manpower Spectrograph design (in2p3/insu)

31. 31 PersonnelActivity FTE FY04 FY05 Dr.E.Barrelet*Detector/Electronic lead 0.8 Dr.G.SmadjaFocal plane lead 0.5 Mr.A.CasteraDetector engineering 0.4 Mr.C.GirerdElectronic engineering 0.5 Mr.DetournayDAQ software 0.3 Mr.Genat*Electronic engineering 0.5 Mr.R.Sefri*Electronic engineering 1. Mr.Lebollo*Electronic engineering 0.6 C.JuramyPHD 1. D.VincentMechanic 0.3 R&D detector/electronic(in2p3) R&D detector/electronic(in2p3) * Involved in the SNAP electronic effort see Von Der Lippe presentation

32. 32PLANNING

33. 33Summary The spectrograph : A key instrument for the SNAP mission Instrument based on integral field technique and slicer unit Technology R&D is well in phase with SNAP France team will take in charge the complete instrument with CNES/CNRS funding Development plan to CDR —risk assessments —R &D activities on detectors and validation —Slicer prototype validation to TRL6 —Develop integration & test plans —Performance specifications & tolerance analysis —Develop conceptual design —Develop preliminary cost & schedule ranges —Develop preliminary interface control specifications/documents