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