Integral Field Spectrograph

1
Integral Field Spectrograph

• Anne EALET
• CNRS (IN2P3) FRANCE,
• Instrument Scientist
• Eric PRIETO
• CNRS,INSU,France,Project Manager
• 11 November 2003

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Spectrograph Background
magnitude
imager
SNAP
ID Ia
spectro
?M , ?L

• A contribution supported by CNRS (IN2P3 INSU)
  and the French space agency (CNES)
• No exchange funding, non US cost

See overview in S.Perlmutter/M.Levi talks
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Spectrograph Overview

• Spectrograph studies
• Science driver
• Requirements for the Spectrograph
• Spectrograph concept and Status
• Risk analysis
• RD French activities
• Slicer prototype
• Detector and electronics
• RD plan
• Summary

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Specifications

• A spectrograph dedicated for SN physics
• Identification of SNIa Si 6150 A line up to
  z1.7 (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)

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Requirements

• An instrument minimizing exposure time for faint
  SN
• Wavelength range 0.35-1.7 mm
• 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)

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Spectrograph characteristics
Property Visible IR
Wavelength coverage (?m) 0.35-0.98 0.98-1.70
Field of view 3.0" / 6.0" 3.0" / 6.0"
Spectral resolution, l/dl 70-200 70-100
Spatial resolution element (arc sec) 0.15 0.15
detectors LBL CCD 10 mm HgCdTe 18 mm
Efficiency with OTA and QE gt40 gt40
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Spectrograph concept
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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

INTEGRAL FIELD TECHNOLOGY reconstruct a DATA
CUBE 3D (x,y,l) image of the sky use a technique
to rearrange the 2D (x,y) in a 1D equivalent
long slit gt sliced the field
Trade-off
X (pixel)
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CONCEPT

• 3D spectroscopy with integral field technology
• Integral Field using the new generation of Image
  Slicer
• DisperserPrism 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
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Spectrograph Functional Overview
Science Software
Operation
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Spectrograph design status
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Instrument design road map
Primary SNAP specifications
First requirements
Define system requirements
Concept definition
2002
Pre conceptual design
Detailed simulation
Prove the feasibility
Interface control document
2003
RD SLICER AND DETECTORS/ ELECTRONIC
New requirements
Verify performances Budget errors
Conceptual design
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Pre optical design

• optics with 7 mirrors
• two arms configuration
• Two prisms

entrance
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Spectrograph implementation
Under the global shielding
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Opto-mechanical concept

• First studies on
• Mechanical environment
• Thermal analysis
• Modal analysis
• interface with SNAP

Dimension lt 400 mm Weight lt 15 Kg Material
Invar Kinetical mount

• Global shielding local shielding around
  detector
• (focal plan)
• Thermal study (LBNL)
• T gt 100 K

Details in E.Prieto talk
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Focal plan development
Mechanical/thermal/interface studies to define a
preliminary design
No single point failure gt Detectors should
to be duplicated two detectors and their
electronic Field of view of 3X6 instead of
3X3 Need 40 slices No effect on optic
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Spectrograph issues

• Focal plane
• Visible detector very low noise versus cosmic
  ray radiation
• lower integration time because of radiation gt
  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!

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Instrument simulation
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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)

Ne
Exemple of a spectrum at z1.7
Background
pixels

• 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

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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

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instrument roadmap

• Scientific and technical requirement
• 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
• Focal Plane
• Review of detectors/technologies choice
• Early focal plane development
• Slicer
• Slicer technology pushed to TRL 6
• adaptation to SNAP
• Calibration procedures studies
• Software development data processing/monitoring
  
• Interface control requirement

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RD Risk analysis
risk mitigation activity completion
Slicer development ESA/NGST prototype 30 elmts in space environment TRL6 end 2003 Snap adaptation 2005
Focal plane Detector technology trade-off Early focal plane development RD on detector and readout electronic Detector choice and Concept Design 2005
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• RD activities

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Ongoing RD slicer

• Slicer development and validation to TRL6 level
  (ESA funding)
• Prototype ready at LAM
• Test on visible and IR
• First test results (see eric talk)

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

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RD detectors/electronic

• IR
• Detectors
• MUX received
• Prototype ordering HgCdTe 1kx1k cut off at 1.7
  mm 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

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Spectrograph RD deliverables
Deliverable Completion Status
Trade decision slicer technology-TRL5 Mar-01 done
Baseline specifications Jul-02 done
Performance requirements Nov-03 draft
Science and technical trade studies Nov-03 draft
Pre-conceptual design Nov-03 done
Interface control requirement with SNAP Nov-03 draft
Calibration procedures studies Dec-03 draft
Slicer prototype report TRL6 May- 04
Review on detector/ decision Sep-04
Detector confirmation Dec-04
Instrument concept/ZDR Dec-04
Focal plane development plan Jul-05
SNAP Slicer prototype development Jul-05
Interface control requirement with SNAP Jul-05
Conceptual design report/review Jan-06
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Spectrograph RD Manpower
Team Activity FTE Associated spectro FY04/05 FY04/05 FTE Associated spectro FY04/05 FY04/05
INSU/CNRS European team Generic slicer for space application 10 2.5
IN2P3/INSU/CNRS Euro 3D Software for 3D spectrograph 10 2
RD effort within the SNAP collaboration and
outside the collaboration Sharing development
when possible
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RD Manpower Spectrograph design (in2p3/insu)
Personnel Activity FTE FY04 FY05 FTE FY04 FY05
Dr.A.Ealet Instrument Scientist 0.8 0.8
Mr.E.Prieto P.Manager/Optic lead 0.5 0.5
Mr C.Macaire Slicer/optical engineering 0.5 0.5
TBC Optical engineering 0.2 0.5
Mr.P.E.Blanc Mecha. /thermal lead 0.5 0.5
Mr.C.Rossin Thermal designer 0.2 0.3
Mr.P.Levacher Electronic control engineering 0.2 0.2
Dr.A.Bonissent Software lead 0.8 0.8
Dr.A.Tilquin Simulation 0.5 0.5
Dr.P.Ferruit Calibration 0.2 0.5
M.Aumeunier PHD/simulation/optic 1. 1.
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RD detector/electronic(in2p3)
Personnel Activity FTE FY04 FY05 FTE FY04 FY05
Dr.E.Barrelet Detector/Electronic lead 0.8 0.8
Dr.G.Smadja Focal plane lead 0.5 0.5
Mr.A.Castera Detector engineering 0.4 0.4
Mr.C.Girerd Electronic engineering 0.5 0.5
Mr.Detournay DAQ software 0.3 0.3
Mr.Genat Electronic engineering 0.5 0.5
Mr.R.Sefri Electronic engineering 1. 1.
Mr.Lebollo Electronic engineering 0.6 0.6
C.Juramy PHD 1. 1.
D.Vincent Mechanic 0.3 0.3
Involved in the SNAP electronic effort see Von
Der Lippe presentation
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PLANNING
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Summary
The spectrograph A key instrument for the SNAP
mission Instrument based on integral field
technique and slicer unit Technology RD 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
• RD 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