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QUIET Q/U Imaging ExperimenT. QUIET Project Miami Physics Conference 2009 December 16 Raul Monsalve for the QUIET Collaboration University of Miami. What is QUIET ?. Radiotelescope that measures intensity and polarization of the CMB Located in Chile - PowerPoint PPT Presentation
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QUIETQ/U Imaging ExperimenT
QUIET Project
Miami Physics Conference 2009December 16
Raul Monsalve for the QUIET CollaborationUniversity of Miami
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
CALTECH
STANFORD
FERMILAB
U. CHICAGO
COLUMBIA
U. MIAMI
JPL
SITE
MANCHESTER
OSLO
MPI-BONN
KEK
PRINCETON
OXFORD
QUIET Collaboration
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
Status and Forecast on the EE and BB characterization
Science Goals
Site and Instrumentation
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%
Q Band W Band
Frequency 40 GHz 90 GHz
N° of HEMT Detectors
17/2 84/6
Resolution 28 arcmin (FWHM) 12 arcmin (FWHM)
Telescope Type Crossed Dragone Crossed Dragone
Module Sensitivity 300 μK s½ 550 μK s½
Array Sensitivity 70 μK s½ 60 μK s½
Observation Period Oct 2008 – June 2009 June 2009 – Mid 2010 ?
Phase-I Summary
Mount
• Inherited from CBI• Alt-Az axes• Rotation about optical axis (boresight axis)• Elevation range limited to 43 deg < el < 87 deg
Optics
• Crossed Dragone design • 1.4 m primary and secondary mirrors• FWHM: 28 (Q) and 12 (W) arcmin
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
OMTs
• Splits incoming radiation into L and R• 20% bandwidth• Low loss• High isolation on the output ports to avoid temperature-to-polarization leakage
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
Module/OMTs
Seven element demonstration array
Receiver
Calibration and Preliminary
Data
Polarization
MOONOnce/7 days,
Relative Gains,Angles
NOISE SOURCEOnce/1.5 hours,Relative Gains,
Angles
TAU AOnce/2 days,
Absolute Gains,Angles, Beams
SKY-DIPOnce/1.5 hours,Relative Gains,
Stability
JUPITEROnce/7 days,
∆T Gains,Beam
Gain Stability
Temperature
Calibration Strategy
+ supplemental measurements
Beam Shape using Jupiter
Calibration
Tau A Gains
Moon Polarization Fits
Calibration
CMB Analysis
Observation Regions
4x(15x15)=900 [deg²]
Patch Centers
• Low foreground regions in coordination with ABS, Polarbear (Multifrequency measurements for galactic foreground removal)• Distribution to allow continuous scanning
Average 68.1%
Downtime mainly due to:-Mechanical Problems-Generator problems-Bad weather
Telescope Operation during Q-Band Season
Phase-I, EE Power-spectra Forecasts
Q W
Patch 2a Results (PRELIMINARY)
Other Interesting ObservationsGalactic Center Polarization Maps with Q-Band Data (PRELIMINARY)
Other Interesting ObservationsGalactic Center Temperature Map with Q-Band Data (PRELIMINARY)
QUIET WMAP
Phase-II
Phase-II Summary
Ka Band Q Band W Band
Frequency 32 GHz 40 GHz 90 GHz
N° of modules (P/T) 16/2 55/6 1389/108
Beamsize (FWHM) 28 arcmin 20 arcmin 8.5 arcmin
Module Sensitivity 165 μK s½ 178 μK s½ 364 μK s½
Beginning operations 2013 ?
N° of telescopes 3
Telescope type Crossed Dragone
Phase-II Power-spectra Forecasts
Current Performance Likely Improvement (noise, duty cycle, 1/f)
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)
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
Systematic Errors
o Overall signal sizeo Overall gain calibrationo Beamsize calibrationo Pointing error
o Fake signal sourceo Instrumental I->Q/U : caused by OMT, 1% for Q-band. Negligible. o Gain fluctuations : up to 20% negligible for phase I.
o E->B mixing sourceo Polarization angle : calibration better than 5% for phase I. o Optics cross polarization : only affects by order of ∆ө²o Q/U gain mismatch : relative gain between Q and U stable.o Patch geometry : finite patch, patch irregularity, pixelization
Systematic Errors
E->B, Patch geometry