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.