EBEX The E and B EXperiment

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EBEXThe E and B EXperiment

• Will Grainger
• Columbia University
• Moriond 2008

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Collaboration
Columbia University Amber Miller Britt
Reichborn- Kjennerud Will Grainger Michele
Limon Harvard Matias Zaldarriaga IAS-Orsay Nicol
as Ponthieu Imperial College Andrew
Jaffe Lawrence Berkeley National Lab Julian
Borrill
McGill University Francois Aubin Eric Bisonnette
Matt Dobbs Kevin MacDermid Oxford Brad
Johnson SISSA-Trieste Carlo Baccigalupi Sam
Leach Federico Stivoli University of
California/Berkeley Adrian Lee Xiaofan Meng Huan
Tran
University of California/San Diego Tom
Renbarger University of Minnesota/Twin
Cities Asad Aboobaker Shaul Hanany (PI) Clay
Hogen-Chin Hannes Hubmayr Terry Jones Jeff
Klein Michael Milligan Dan Polsgrove Ilan
Sagiv Kyle Zilic Weizmann Institute of Science
Lorne Levinson
APC Paris Radek Stompor Brown
University Andrei Korotkov John Macaluso Greg
Tucker Yuri Vinokurov CalTech Tomotake
Matsumura Cardiff Peter Ade Enzo Pascale
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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

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Science Goals

• Detect (or set upper bound) in inflationary
  B-mode
• T/S lt 0.02 at 2s (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
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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 l20 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

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Design
250 cm
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Cryostat and Optics

• Reflecting Gregorian Dragone telescope
• Control of sidelobes Cold aperture stop

Stop

• Polarimetric systematics Half Wave Plate
• Efficiency Detection of two orthogonal states

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Focal Planes
Single TES
738 element array
150
250
410
2.1 mm
3 mm
Strehlgt0.85 at 250 GHz
Meng, Lee, UCB

• 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 µKrt(sec) (150 GHz)
• msec,

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Detector Readouts

• SQUID arrays (NIST)
• Digital Frequency Domain Multiplexing (McGill)

FPGA Synthesizes Comb Controls SQUIDs
Demodulates

• LDB 495 Watt for x12 406 Watt for x16

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Half Wave Plate Polarimetry

• 5 stack achromatic HWP
• 0.98 efficiency for 120lt ? lt 420 Ghz
• 6 Hz rotation
• lt 10 attenuation from 3 msec time constant
• Driven by motor outside cryostat via Kevlar belt
• Supported on superconducting magnetic bearing

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EBEX Scan

• Scan 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 108 samples/beam

17 deg p-p / 0.7 deg/sec
x4
. . . . .
102 steps
6 hours
All 150 GHz detectors, 14 Day
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Gondola Pointing
Cable Suspension (a-la BLAST) Pointing System
(BLAST, MAXIMA, Boom) Gondola integrated at
Columbia U. Pointing tests ongoing
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EBEX Summary Schedule

• 14 day flight
• 420 deg2
• 24,000 8 pixels
• Low dust contrast (4mK rms)
• 796, 398, 282 TES detectors at 150, 250, 410
  GHz
• 0.7 mK/8 pixel - Q/U
• 0.5 mK/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

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Nothing to see here
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Optics

• Reflecting Gregorian Dragone telescope
• Control of sidelobes Cold aperture stop
• wide range of ls probed.

Stop

• Polarimetric systematics Half Wave Plate
• Efficiency Detection of two orthogonal states

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Design
Blue Synchrotron Pink Dust Minimize
synchrotron by going to high frequency, then only
one foreground to deal with.
250 cm