The EBEX Michele Limon Columbia University Inflation Probe Systematics Workshop Annapolis, MD July 28-30
Collaboration APC Paris Radek Stompor Brown University Andrei Korotkov John Macaluso Greg Tucker Yuri Vinokurov CalTech Tomotake Matsumura Cardiff Peter Ade Enzo Pascale Columbia University Daniel Chapman Will Grainger Seth Hillbrand Michele Limon Amber Miller Britt Reichborn- Kjennerud Harvard Matias Zaldarriaga IAS-Orsay Nicolas 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 Minnesota/Twin Cities Asad Aboobaker Shaul Hanany Hannes Hubmayr Terry Jones Jeff Klein Michael Milligan Dan Polsgrove Ilan Sagiv Kyle Zilic Weizmann Institute of Science Lorne Levinson
Science Goals I 1. Detect or set upper bound on inflation B-mode If r = 0.1, S/N>5 Restrict r to ~x10 better than now: r < 0.02 at 2 (excluding systematic and foreground subtraction uncertainties) EBEX 14 days Planck 1 year Black Curves: EE and BB for r = 0.1
Science Goals II 1. Detect or set upper bound on inflation B-mode 2. Detect the lensing B-mode - 5% error on amplitude of lensing power spectrum 4
Experiment Details Angular resolution 8 Arcminutes Frequency Coverage 150, 250, 410 GHz Sky Coverage 420 Square Degrees Multipole Coverage 20-1500 - Polarization Modulation? Half-Wave Plate - Types of Detectors TES Bolometers - Location Balloon Balloon/Ground/Space Instrument NEQ 5.0 at 150 GHz µk s 1/2 Expected/Current =.1 at 5 - limit on r <.02 at 2 Status Funded Funded
Gondola Design Beam Secondary Mirror Support Inner Frame Tower Primary Mirror Support Cryo Dummy Suspension Cables Reaction Wheel Cable Suspension Designed at SSL (Berkeley) Integration at Nevis Lab at Columbia Outer Frame Table
Optics 1.5 m Aperture Gregorian Dragone telescope allows for sensitivity to lensing B-mode scales Cold aperture stop -- control of sidelobes Achromatic Half Wave Plate on magnetic bearing -- strong rejection of polarimetric systematics Wire Grid Analyzer -- Detection of two orthogonal states
Focal Plane 738 element array 139 element decagon Single TES 250 150 Meng, Lee, UCB 150 410 150 150 250 3 mm 30 cm Strehl>0.85 at 250 GHz Total of 1476 detectors Maintained at 0.27 K 3 frequency bands/focal plane 8.6 cm 2.1 mm G = 10 pwatt/k NEP = 1.1e-17 (150 GHz) NEQ = 136 K*rt(sec) (150 GHz) msec, 8
Scan Profile: Constant elevation Speed: ~5 x (Q,U) per full beam Multiple visitations per pixel Scan + Coverage Scan Map for all (796) 150 GHz, 14 Days (sample/beam in color scale) 4 hours 17 deg p-p at 0.7 deg/sec x2 Then repeat Scan Patch Coverage and Scan Area: Relatively uniform coverage Up to 10 8 samples/beam Scan area 420 deg 2 Low dust contrast (4µK rms) 9
Half Wave Plate Polarimetry Encoder Data vs. Synthetic Wave HWP prototype bonded + thermally cycled ARC prototype bonded + thermally cycled AHWP now being bonded @ Cardiff Magnetic bearing tested end-to-end 0.25 degree angular encoding limited by sampling (0.3 deg required) Volts 20 80 100 Samples 10
Half Wave Plate Polarimetry Half Wave Plate demonstrated successfully on MAXIPOL EBEX 5-stack achromatic HWP 0.98 efficiency for 120<ν<450 GHz single and 3-stack (Hanany et al. 2003) Rotate at 6 Hz Signal at 24 Hz <10% attenuation from 3 msec time constant TES
Systematic Requirements Overall criterion the contamination from systematic effect should be be controlled to 5 less than the 2 sigma upper limit of 0.02 Effect Size Polarization rotation 0.3 Pointing uncertainty 9 arcsec Instrument Polarization 0.05% Polarization efficiency >90% Sidelobes response 85 db
Polarization Rotation Polarization rotation needs to be characterized to better than 0.3 Given our optical system we have to correct for it Code V simulation B (T/S = 0.1 + lensing) 10 1 0.1
Ground-based: Artificial planet Experimental set-up in high bay Artificial planet Cables to crane Box beam structure to support source/ chop/grid ~ 20 m EBEX Cables to ground for az/el position + stability Rotating grid Chopper 1300K Blackbody
Polarization Rotation Flight Data Split PR to overall rotation (common to all detectors) Individual rotation (of each relative to the mean) Overall Rotation Produces specific EB (and TB) cross-correlation (TB comes from TE) EBEX can detect 0.04 degree with s/n=1 Relative Rotation Require that all detectors see same Q,U per pixel: get 0.1 Caveats: Relies on no leakage from EB separation (finite patch) Effects of foregrounds residuals (not quantified)
Pointing B (T/S = 0.1 + lensing) 500 1000 100 Pointing reconstruction needs to be better than 9 arcsec BLAST demonstrated 4 arcsec RMS pointing reconstruction using a similar pointing system
Instrumental Polarization (I) IP needs to be characterized to better than 0.05% B (T/S = 0.1 + lensing).5%.1%.02%
Instrumental Polarization (II)
Instrumental Polarization (III) WMAP (3yr) EBEX w/ 100 x noise EBEX nominal noise B (T/S = 0.1 + lensing) Reflections, Refraction and Emission Dominated by the AR coating of the first lens Can be characterized and removed to 0.01% using measurements of the CMB dipole Differential Absorption, Reflection and Emission HWP differential absorption 0.2% HWP differential reflection ~2% This signal is at 2f o and the leakage at 4f o is calculated to give rise to a negligible 10-7 polarization signal
Concerns HWP phase (Ebert Fastie) Many of the systematics mitigation techniques (dipole IP, pol. Rotation) rely on good e-b separation. (Foregrounds coupling to systematics)
Ebert-Fastie Monochromator x-y translation stage Polarized narrow-band mm-wave light Ebert-Fastie monochromator fold len s Ebert-Fastie EBEX cryostat len s grid Diffraction grating BB chopper mirror EBEX cryostat Relative spectral response + polarization calibration
Ebert-Fastie Monochromator (cont.) 150.0 112.5 Nominal operation: 10 narrow emission bands generated by Ebert-Fastie as function of grating angle (across full EBEX 150 GHz band) signal (mv) 75.0 37.5 0-50 -45-40 -35-30 -25-20 -15-10 -5 0 5 10 15 20 25 30 35 40 45 50 grating angle (deg) Performance confirmation data: Diffraction peaks observed where predicted using discrete 110 GHz source & detector 22
E-B Separation Smith + Zaldarriaga 06010059 10 degree circular patch 5.75 micro*k arcmin
EB Separation
EB separation
EB separation
EB separation
EB separation
EB separation
EB separation
Calibration Error
Calibration Error