Transcript NGAO_Instrumentation_B2C_v2.ppt

NGAO Science Instruments
Build to Cost Status
February 5, 2009
Sean Adkins
Introduction
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Approach to design/build to cost
1. Be sure instrument capabilities are well matched to key science
requirements
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Galaxy assembly & star formation history
Nearby Active Galactic Nuclei
Measurements of GR effects in the Galactic Center
Imaging & characterization of extrasolar planets around nearby stars
Multiplicity of minor planets
2. Understand which requirements drive cost
3. Resist the temptation to add features
4. Seek novel ways to save cost
a. Exploit redundancies in compatible platforms – e.g. Near-IR imager and
Near-IR IFS
b. Evaluate ways to break the normal visible/near-IR paradigm of using
different detectors
c. Work on the problem hard enough to allow creativity to offer more options
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Overall Performance Requirements
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High Strehl
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Spatial resolution
Sensitivity
Contrast
Wavelength coverage
Required for AGN, GC, exoplanet & minor planet key science cases
Imaging
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Diffraction limited, 2 to 3 pixel sampling
Available over full AO system wavelength range
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Background limited performance
Simple occulting spot coronagraph for 0.97 to 2.4 µm
High sky coverage
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0.97 to 2.4 µm required for all key science cases
To ~820 nm required for AGN, highest spatial resolution
Priority for all key science cases
Integral Field Spectroscopy
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Diffraction limited sampling (~20 mas)
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Larger sampling scales for galaxy assembly and star formation history (50 to 100 mas)
To ~820 nm
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AGN, GC
Required for AGN, highest spatial resolution
Desired at ~50 mas for gravitational lensing
FOV ≥ 4“ dia. (all except galaxy assembly)
Spectral resolution ~4000 (for line discrimination, OH removal)
Background limited performance
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IFS/Imager
Structures
Requirement
Wavelength Coverage
Spectral Resolution
FOV
Spatial Sampling
@ 820 nm
@ 1µm
Filter Selection
Detector Performance
IFS
Imager
z, Y, J, H, K (0.818 to z, Y, J, H, K (0.818 to
2.4 µm)
2.4 µm)
~4000
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≥ 4" dia.
~30" dia.
8.5 mas
10 mas
Narrowband,
Broadband
Background limited
2 pixel = 8.5 mas
3 pixel = 6.7 mas
Photometric, Ks
Background limited
• Some clear commonalities
• It remains clear that for
>$9M we have a challenge
if we need to deliver more
than one instrument
Near-IR IFS
Instrument
Dewar
Cold Assemblies
Dewar Internal Structure
Input Baffle
Fore Optics
Pupil Imager
Scale Changer
Adjustable Lyot Stop
Filter Wheels
Image Slicer
Collimator
Grating Selector
Camera
Detector Head
Warm Assemblies
Dewar Shell
Window
External Connections
Vacuum System
Cryogenic System
Electronics
Detector
Detector Control
Motion Control
Power Control
Pressure Monitoring
Temperature Monitoring and Control
Cabling and Interconnections
Software
Global Server
Motion Control
Power Control
Pressure Monitoring
Temperature Monitoring and Control
User Interfaces
Data Reduction Tools
Interfaces
Mechanical
Electronic
Software
Accessories
Alignment Tooling
Assembly Tooling
Manuals and Documentation
Near-IR Imager
Instrument
Dewar
Cold Assemblies
Dewar Internal Structure
Input Baffle
Fore Optics
Re-imager
Deployable Coronagraph Spot
Adjustable Lyot Stop
Filter Wheels
Camera
Detector Head
Warm Assemblies
Dewar Shell
Window
External Connections
Vacuum System
Cryogenic System
Electronics
Detector
Detector Control
Motion Control
Power Control
Pressure Monitoring
Temperature Monitoring and Control
Cabling and Interconnections
Software
Global Server
Motion Control
Power Control
Pressure Monitoring
Temperature Monitoring and Control
User Interfaces
Data Reduction Tools
Interfaces
Mechanical
Electronic
Software
Accessories
Alignment Tooling
Assembly Tooling
Manuals and Documentation
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IFS Parameter Flow down
Wavelength coverage
Wavelength range
Number of filters
Detector selection
Optical design
Full band coverage
Spatial sampling format
Spatial sampling scales
Lower short λ cut-off
Detector selection
Optical design
Spectral resolution
~4000
Grating orders
Grating tilt selection
Grating size, ruling density
Field of view
Selection of spatial sampling scales
Spatial sampling format
Detector efficiency
Collimator and camera aperture
Spatial sampling
Spatial sampling (at λ/D)
Spatial sampling format
Detector efficiency
Collimator and camera aperture
Selection of spatial sampling scales
Scale changing optics
Detection sensitivity
SNR for velocity precision
AO Background
AO Throughput
AO Strehl
Instrument background
Scattered light and ghosting
Instrument photon efficiency
Throughput
Detector QE
Wavefront error
Spectral quality
Line FWHM
Crosstalk
Sensitivity & SNR
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Wavelength Coverage
100.00%
90.00%
80.00%
Y
J
K
H
Transmission, %
70.00%
NGAO
z spec
60.00%
NGAO z'
50.00%
NGAO i'
40.00%
NGAO rl
30.00%
NGAO visible
20.00%
NGAO near-IR
10.00%
0.00%
0.3 0.4 0.5 0.6 0.7 0.8 0.9
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1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
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2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9
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Wavelength, mm
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Visible and Near-IR Detector QE
LBNL QE
H2RG QE
100.00%
90.00%
80.00%
Transmission, %
70.00%
60.00%
Teledyne min. spec. for
substrate removed
H2RG
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
0.5
0.6
0.7
0.8
0.9
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1.1
1.2
Wavelength, mm
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Detector Performance
• Visible CCD, read noise 4 e-, ~20% higher than H2RG
• H2RG single CDS read noise 15 e10
Coadded Exposures 10eFowler Sampling
0.1
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10
100
Signal
1000
Single Exposure, 10000 e-
SNR
SNR
Single Exposure, 10e1
Coadded Exposures, 10000 eFowler Sampling
100
10000
100000
Signal
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