Status of QUIET

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Status of QUIET

• Sarah Church for the QUIET collaboration

Max-Planck-Institut fur Radioastronomie Bonn,
Caltech, Columbia University, JPL, Kavli
Institute for Cosmological Physics at the
University of Chicago, Kavli Institute for
Particle Astrophysics and Cosmology at the
Stanford University, KEK, University of
Manchester, University of Miami, University of
Oslo, University of Oxford, Princeton University
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QUIET aims to produce very deep polarization maps
Stokes Q over a 400 square degree patch Beam FWHM
0.15 deg
Large scale W-band sensitivity
Phase I 400 nK/deg2 Phase II 85 nK/deg2
H.K. Eriksen
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QUIET overview

• Phase 1
• 19-element 40 GHz (Q-band) arrived Chile July
  2008
• 91-element 90 GHz array (Jan 2009)
• 1.4 m telescope
• Phase II
• 100 Q-band
• 1000 W-band
• More/larger telescopes

• QUIET will be located on the CBI mount on the
  Chajnantor Plateau

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Modular Correlation Radiometers

• Quiet W band module
• 18 GHz band width
• Simultaneous Q/U measurements

CAPMAP W-band correlation radiometer

• Performance goals
• 160 (250) uK s1/2 per pixel to both Q and U at 40
  (90) GHz
• Currently 1.75-2 times away from these numbers

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The QUIET modules
OMT
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Principle of Operation
4kHz phase switching
Lock-in to phase switch frequency gives Q
Lock-in to phase switch frequency gives Im(RL),
which is U
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QUIET Receiver (W band)
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Platelet method used to make arrays of corrugated
feeds
Q band
W band
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The QUIET 1.4m telescope

• Side-fed Dragone system
• Measured at W-band (90 GHz) with no ground shield

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Co-moving absorbing groundshield is used to
intercept sidelobes
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Observing Strategy

• Observe 4 patches spread approximately even in
  Right Ascension on the sky
• All 4 can be seen each day with 24hr observing
• Or, observe 2-3 per night and rotate the choices
  with the season
• The CMB fields will be scans of 10deg in length,
  so FOV 200 square degrees
• Q-band foregrounds will probably be mostly
  synchrotron emission, perhaps with a bit of
  anomalous emission

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QUIET Foregrounds

• Two reasons for optimism
• Can get a good handle on foregrounds by even
  modestly splitting bands, since the modules can
  be set to slightly different frequencies
• Choose the cleanest of patches on which to go
  deep
• For the future QUIET will
• Coordinate to observe the same patch with an
  experiment having 150 GHz capability
• Possibly consider some channels at 30 GHz

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W
Q
T

• Q

U
P
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Status Q-band receiver telescope shipped in
late June
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Q-band forecast

• Based on measured noise performance of 19
  elements
• 10 months observing with a 50 duty cycle
• W band will improve this still further (91
  elements)