Design of SPICA focal plane assembly

1
Design of SPICA focal plane assembly

• Hirokazu Kataza (ISAS/JAXA)

2
Focal Plane Instruments

• Following instruments are assumed for the system
  design
• Core wavelength coverage 5 to 200mm
• Mid-Infrared Coronagraph
• Mid-Infrared Camera and Spectrometer
• Far-Infrared Camera and Spectrometer
• Additional wavelength coverage
• Near-Infrared
• Sub-mm

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Mid-Infrared Coronagraph

• Wavelength 5 to 27mm
• Spectrometer after coronagraph
• 0.06 arcsec/pixel (1/6xl/D _at_ l5mm)
• 1 arcmin2 FOV
• Under investigation
• Type of the coronagraph
• Sensitivity limit (dynamic range limit) with
  SPICA telescope

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Mid-infrared camera spectrometer

• Wavelength coverage 5 to 38mm
• FOV 6.1 arcmin2 for imaging
• A few ( at least 2, may be 3) camera
  spectrometer for total wavelength coverage
• Slit viewer capability
• 3D spectrometer is preferable

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Far-infrared camera spectrometer

• SW
• Extrapolation from ASTRO-F FIS SW channel
• Detector GeGa ll 50 100 mm
• 1.8 arcsec/pixel (1/2xl/D _at_ l50mm)
• 0.9 arcsec/pix is better for super resolution
• FOV 3.8 arcmin2 (256 pix2)
• LW
• If stressed GeGa is available, ll 100 - 200 mm
• 3.6 arcsec/pixel (1/2xl/D _at_ l100mm)
• FOV 3.8 arcmin2 (128 pix2 !)
• Fourier spectrometer is assumed to estimate data
  rate.

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How we can cover 40-50mm?

• No good detector is available now
• GeBe ?
• Bolometer ?

7
Additional wavelength coverage

• Near-Infrared capability
• At least, we need several star sensors on focal
  plane
• FOV 1 arcmin2
• Many people want near infrared capability
• Sum-mm capability
• Not included in system design

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Focal Plane dividing plan
preliminary plan

• Center Rlt4.5 arcmin
• Good PSF with wide-field
• Min-Infrared
• Coronagraph
• Small FOV with good PSF
• Whole field of view is R15 arcmin

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Unique features of SPICA

• Good PSF is expected
• Telescope should be good enough
• Pointing system is challenging
• Light weight mirror
• No real test under zero-G
• Warm launch including instruments
• Instruments should survive and be healthy after
  many pre-launch tests

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Key points

• Do we need AO for the coronagraph?
• Probably YES
• Tip-tilt tracking mirror in instruments
• Long slit (or image slicer) spectrometer require
  accurate pointing

AO
Coronagraph
Tip-tilt pickup mirror
Mid-Infrared Instruments
Focal Plane
Far-Infrared instruments
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How to test?

• Well considered design and strategy for testing
  is a key for SPICA instrument.
• End-to-end test under cryo-environment is very
  difficult.
• Light sources on the focal plane?