EBEX The E and B EXperiment
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Transcript of EBEX The E and B EXperiment
EBEXThe E and B EXperiment
Will Grainger
Columbia University
Moriond 2008
CollaborationAPC – ParisRadek Stompor
Brown UniversityAndrei KorotkovJohn MacalusoGreg TuckerYuri Vinokurov
CalTechTomotake Matsumura
CardiffPeter AdeEnzo Pascale
Columbia UniversityAmber MillerBritt Reichborn- KjennerudWill GraingerMichele Limon
HarvardMatias Zaldarriaga
IAS-OrsayNicolas Ponthieu
Imperial CollegeAndrew Jaffe
Lawrence Berkeley National LabJulian Borrill
McGill UniversityFrancois Aubin Eric Bisonnette Matt DobbsKevin MacDermid
OxfordBrad Johnson
SISSA-TriesteCarlo BaccigalupiSam LeachFederico Stivoli
University of California/BerkeleyAdrian LeeXiaofan MengHuan Tran
University of California/San DiegoTom Renbarger
University of Minnesota/Twin CitiesAsad AboobakerShaul Hanany (PI)Clay Hogen-ChinHannes HubmayrTerry JonesJeff KleinMichael MilliganDan PolsgroveIlan SagivKyle Zilic
Weizmann Instituteof Science Lorne Levinson
EBEX in a Nutshell
• CMB Polarization Experiment
• Long duration, balloon borne
• Use 1476 bolometric TES
• 3 Frequency bands: 150, 250, 410 GHz
• Resolution: 8’ at all frequencies
• Polarimetry with half wave plate
• BLAST (+ BOOM, MAXIMA) balloon technologies
Science Goals
• Detect (or set upper bound) in inflationary B-mode – T/S < 0.02 at 2σ
(excluding systematic and foreground subtraction uncertainty)
• Detect lensing B-mode– 5% error on amplitude of
lensing power spectrum• Measure E-E power
spectrum• Determine properties of
polarized dust
EBEX, 14 days
Dust Determination and Subtraction
• Simulate CMB B, dust, noise• Reconstruct dust + CMB maps (using the parametric separation technique) • Less than 1/3 increase in error on recovered CMB over binned cosmic variance and instrument noise due to foreground subtraction for l=20 to 900.
• Reconstruction of dust spectral index within 5%
• Blue = INPUT dust model• Red = INPUT CMB + instrument noise + sample variance• Black dust = data + errors of reconstruction• Black CMB = variance of 10 simulations• No systematic uncertainties
Design
250 cm
Cryostat and Optics
• Polarimetric systematics: Half Wave Plate
• Efficiency: Detection of two orthogonal states
Stop +
• Reflecting Gregorian Dragone telescope
• Control of sidelobes: Cold aperture stop
Focal Planes
738 element array Single TES
Strehl>0.85 at 250 GHz3 mm
• Total of 1476 detectors• Maintained at 0.27 K• 3 frequency bands/focal plane• G = 10 pWatt/K • NEP = 1.1e-17 (150 GHz)• NEQ = 136 μK*rt(sec) (150 GHz)• msec, 3
Meng, Lee, UCB
2.1 mm
150250
410
36 cm
• SQUID arrays (NIST)
• Digital Frequency Domain Multiplexing (McGill)
Detector Readouts
• LDB: 495 Watt for x12; 406 Watt for x16
FPGASynthesizes Comb; Controls
SQUIDs; Demodulates
• 5 stack achromatic HWP• 0.98 efficiency for 120< ν < 420 Ghz• 6 Hz rotation• < 10% attenuation from 3 msec time constant• Driven by motor outside cryostat via Kevlar belt• Supported on superconducting magnetic bearing
Half Wave Plate Polarimetry
EBEX ScanScan is:
• Constant elevation for 4 repeats, one Q,U per 1/3 beam, (0.7 deg/sec).
• Step in elevation, and repeat; 102 times.
• Repeat that 6 hour block on same patch of sky for 14 days.
• Multiple visitations per pixel from various angles (i.e. crosslinking) on various timescales.
• Relatively uniform coverage
• Up to 10^8 samples/beam
17 deg p-p / 0.7 deg/secx4
..... 102 steps6 hours
All 150 GHz detectors, 14 Day
Gondola + Pointing
Cable Suspension (a-la BLAST)Pointing System (BLAST, MAXIMA, Boom)
Gondola integrated at Columbia U.Pointing tests ongoing
EBEX Summary + Schedule• 14 day flight• 420 deg2 • ~24,000 8’ pixels• Low dust contrast (4K rms)
• 796, 398, 282 TES detectors at 150, 250, 410 GHz
• 0.7 K/8’ pixel - Q/U;
0.5 K/8’ pixel – T
•Currently integrating•detectors into cryostat in UMN•Pointing sensors onto gondola in CU
•North American flight: Autumn 2008•Long Duration (Antarctic) flight: Austral Summer 2009
Nothing to see here…
Optics
• Polarimetric systematics: Half Wave Plate• Efficiency: Detection of two orthogonal states
• Reflecting Gregorian Dragone telescope • Control of sidelobes: Cold aperture stop• wide range of ls probed.
Stop +
Design
250 cm
Blue – Synchrotron
Pink – Dust
Minimize synchrotron by going to high frequency, then only one foreground to deal with.