QUIET

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QUIET Q/U Imaging ExperimenT
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QUIET Project Miami Physics Conference
2009 December 16 Raul Monsalve for the QUIET
Collaboration University of Miami
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What is QUIET ?

• Radiotelescope that measures intensity and
  polarization of the CMB
• Located in Chile
• Main science objective is to improve
  characterization of E-mode polarization and
  detect the difficult B-mode polarization
• Two phases are planned. Phase-I is ongoing,
  started in August 2008. Phase II is planned to
  start in 2012, in a larger scale, improving the
  techniques learned during phase-I

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QUIET Collaboration
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Science Goals

• We can measure the polarisation of the CMB the
  same way as for light
• The Stokes parameters quantify the polarization
  properties of a light ray
• I no filter at all
• Q linear polarizer at 0 and 90
• U linear polarizer at -45 and 45
• V circular polarizer
• I is just the temperature
• Q and U combine to form E- and B-modes
• No known physical process can generate
  V-polarized CMB radiation

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Science Goals
Status and Forecast on the EE and BB
characterization
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Site and Instrumentation
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Site

• Chajnantor Scientific Reserve in Chile at 5080 m
  above sea level
• Among the best places for mm and submm astronomy
• Access to CBI infrastructure
• Accessible at all times
• 1 hour drive from San Pedro de Atacama
• Good sky coverage
• For outside work bottled oxygen systems are used
• Oxygen concentration in control room is
  increased 27

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Phase-I Summary
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Mount

• Inherited from CBI
• Alt-Az axes
• Rotation about optical axis (boresight axis)
• Elevation range limited to 43 deg lt el lt 87 deg

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Optics

• Crossed Dragone design
• 1.4 m primary and secondary mirrors
• FWHM 28 (Q) and 12 (W) arcmin

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Horn Arrays

• Conical corrugated feed horn arrays
• Excellent beam symmetry
• Low sidelobe response
• Low cross-polarization
• Broad frequency band
• Typical FWHM of 7 deg
• Built by UM

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OMTs

• Splits incoming radiation into L and R
• 20 bandwidth
• Low loss
• High isolation on the output ports to avoid
  temperature-to-polarization leakage

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Detector Modules

• Heart of the receiver
• Polarimeter on a chip
• Automated assembly and operation
• Measuring of Q and U simultaneously in each
  pixel
• Operate at 20K

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Module/OMTs
Seven element demonstration array
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Receiver
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Calibration and Preliminary Data
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Calibration Strategy
supplemental measurements
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Calibration
Beam Shape using Jupiter
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Calibration
Tau A Gains
Moon Polarization Fits
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CMB Analysis
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Observation Regions
Patch Centers

• Low foreground regions in coordination with ABS,
  Polarbear
• (Multifrequency measurements for galactic
  foreground removal)
• Distribution to allow continuous scanning

4x(15x15)900 deg²
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Telescope Operation during Q-Band Season
Average 68.1

• Downtime mainly due to
• Mechanical Problems
• Generator problems
• Bad weather

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Phase-I, EE Power-spectra Forecasts
Q
W
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Patch 2a Results (PRELIMINARY)
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Other Interesting Observations
Galactic Center Polarization Maps with Q-Band
Data (PRELIMINARY)
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Other Interesting Observations
Galactic Center Temperature Map with Q-Band Data
(PRELIMINARY)
QUIET
WMAP
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Phase-II
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Phase-II Summary
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Phase-II Power-spectra Forecasts
Current Performance
Likely Improvement
(noise, duty cycle, 1/f)
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Appendix

• Alternate technique to identify gravitational
  lensing effects (Zaldarriaga(1999), Hu(2002))
• Lens reconstruction Lensing Deflection Field
  calculation from cross-correlation of E- and
  B-modes
• Stronger constraints on cosmological parameters
  than using B-mode power spectrum

• By measuring shape and amplitude of the
  Deflection power spectrum QUIET Phase-II can
  place constraints on parameters such as
• Neutrino mass (Maltoni, 2004)
• Dark energy density (Stompor, 1999)
• Spatial curvature (Stompor, 1999)

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Summary

• QUIET Science
• Experiment addressing fundamental questions in
  physics
• Taking the CMB polarization knowledge to new
  levels
• QUIET Status
• Largest HEMT-based focal plane array ever
  deployed, using state of the art MMIC packaging
  techniques
• Phase-I observing and proposing Phase-II to start
  in 2012/2013

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Systematic Errors

• Overall signal size
• Overall gain calibration
• Beamsize calibration
• Pointing error
• Fake signal source
• Instrumental I-gtQ/U caused by OMT, 1 for
  Q-band. Negligible.
• Gain fluctuations up to 20 negligible
  for phase I.
• E-gtB mixing source
• Polarization angle calibration
  better than 5 for phase I.
• Optics cross polarization only affects by order
  of ??²
• Q/U gain mismatch relative gain
  between Q and U stable.
• Patch geometry finite patch,
  patch irregularity, pixelization

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Systematic Errors
E-gtB, Patch geometry