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QUIET

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QUIET – PowerPoint PPT presentation

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Title: QUIET


1
QUIET Q/U Imaging ExperimenT
2
QUIET Project Miami Physics Conference
2009 December 16 Raul Monsalve for the QUIET
Collaboration University of Miami
3
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

4
QUIET Collaboration
5
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

6
Science Goals
Status and Forecast on the EE and BB
characterization
7
Site and Instrumentation
8
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

9
Phase-I Summary
10
Mount
  • Inherited from CBI
  • Alt-Az axes
  • Rotation about optical axis (boresight axis)
  • Elevation range limited to 43 deg lt el lt 87 deg

11
Optics
  • Crossed Dragone design
  • 1.4 m primary and secondary mirrors
  • FWHM 28 (Q) and 12 (W) arcmin

12
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

13
OMTs
  • Splits incoming radiation into L and R
  • 20 bandwidth
  • Low loss
  • High isolation on the output ports to avoid
    temperature-to-polarization leakage

14
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

15
Module/OMTs
Seven element demonstration array
16
Receiver
17
Calibration and Preliminary Data
18
Calibration Strategy
supplemental measurements
19
Calibration
Beam Shape using Jupiter
20
Calibration
Tau A Gains
Moon Polarization Fits
21
CMB Analysis
22
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
23
Telescope Operation during Q-Band Season
Average 68.1
  • Downtime mainly due to
  • Mechanical Problems
  • Generator problems
  • Bad weather

24
Phase-I, EE Power-spectra Forecasts
Q
W
25
Patch 2a Results (PRELIMINARY)
26
Other Interesting Observations
Galactic Center Polarization Maps with Q-Band
Data (PRELIMINARY)
27
Other Interesting Observations
Galactic Center Temperature Map with Q-Band Data
(PRELIMINARY)
QUIET
WMAP
28
Phase-II
29
Phase-II Summary
30
Phase-II Power-spectra Forecasts
Current Performance
Likely Improvement
(noise, duty cycle, 1/f)
31
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)

32
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

33
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34
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

35
Systematic Errors
E-gtB, Patch geometry
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