Title: QUIET
1QUIET Q/U Imaging ExperimenT
2QUIET Project Miami Physics Conference
2009 December 16 Raul Monsalve for the QUIET
Collaboration University of Miami
3What 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
4QUIET Collaboration
5Science 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
6Science Goals
Status and Forecast on the EE and BB
characterization
7Site and Instrumentation
8Site
- 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
9Phase-I Summary
10Mount
- Inherited from CBI
- Alt-Az axes
- Rotation about optical axis (boresight axis)
- Elevation range limited to 43 deg lt el lt 87 deg
11Optics
- Crossed Dragone design
- 1.4 m primary and secondary mirrors
- FWHM 28 (Q) and 12 (W) arcmin
12Horn 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
13OMTs
- Splits incoming radiation into L and R
- 20 bandwidth
- Low loss
- High isolation on the output ports to avoid
temperature-to-polarization leakage
14Detector 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
15Module/OMTs
Seven element demonstration array
16Receiver
17Calibration and Preliminary Data
18Calibration Strategy
supplemental measurements
19Calibration
Beam Shape using Jupiter
20Calibration
Tau A Gains
Moon Polarization Fits
21CMB Analysis
22Observation 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
23Telescope Operation during Q-Band Season
Average 68.1
- Downtime mainly due to
- Mechanical Problems
- Generator problems
- Bad weather
24Phase-I, EE Power-spectra Forecasts
Q
W
25Patch 2a Results (PRELIMINARY)
26Other Interesting Observations
Galactic Center Polarization Maps with Q-Band
Data (PRELIMINARY)
27Other Interesting Observations
Galactic Center Temperature Map with Q-Band Data
(PRELIMINARY)
QUIET
WMAP
28Phase-II
29Phase-II Summary
30Phase-II Power-spectra Forecasts
Current Performance
Likely Improvement
(noise, duty cycle, 1/f)
31Appendix
- 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)
32Summary
- 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(No Transcript)
34Systematic 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
35Systematic Errors
E-gtB, Patch geometry