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POLAR-1 and the POLAR Array

POLAR-1 and the POLAR Array. Chao-Lin Kuo Physics Department & SLAC PPA, Stanford University Kavli Institute for Particle Astrophysics and Cosmology. Collaborators. Harvard John Kovac Minnesota Clem Pryke. Stanford Chao-Lin Kuo Keith Thompson Ki Won Yoon Kimmy Wu

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POLAR-1 and the POLAR Array

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  1. POLAR-1 and the POLAR Array Chao-Lin Kuo Physics Department & SLAC PPA, Stanford University Kavli Institute for Particle Astrophysics and Cosmology

  2. Collaborators • Harvard • John Kovac • Minnesota • Clem Pryke • Stanford • Chao-Lin Kuo • Keith Thompson • Ki Won Yoon • Kimmy Wu • Sarah Church • Caltech/JPL • Jamie Bock • Roger O’Brient • Howard Hui • Marc Runyan • Hien Nguyen • UBC • Mark Halpern • NIST • Kent Irwin • Gene Hilton Supports from NSF-OPP-MRI C. L. Kuo POLAR Array

  3. The South Pole Station; 2015? Image: C. Sheehy & K. Thompson The POLAR Array: * array of multiple mid-size reflectors for CMB polarization * (a few) arcminte resolution * multi-frequency (distribution TBD) * 10% the survey speed of CMBPOL * ~ 12 kW power, 0.1 TB/day data per element

  4. Unlensed pure E-mode C. L. Kuo POLAR Array

  5. Lensing field C. L. Kuo POLAR Array

  6. Lensed B-mode WH Teng C. L. Kuo POLAR Array

  7. Lensing B-mode measurements as of April 2011 H. Chiang • QUaD/BICEP (50~100 detectors) still miss the B-polarization by ~ 2 orders of magnitude. • To perform high S/N imaging of lensing B-polarization, one must increase the survey speed by 102. C. L. Kuo POLAR Array

  8. LensingB-polarization is a LSS experiment • Deep polarization measurements can significantly improve Planck+WFIRST/Euclid’s constraints on {w, Wk, ∑mn} etc., • If one assumes a prior of w0= -1, wa=0, Wk <10-4 → lensing B provides a constraint on ∑mn <0.04 eV • This will either • Detect a neutrino mass • Rule out inverted hierarchy Lesgourgues and Pastor Physics Reports, 2006 also Astro-2010 Panel Reports C. L. Kuo POLAR Array

  9. Neutrino from Cosmology Abazajian et. al. 2011 (primarily for T)

  10. It is possible to “undo” the lensing (delensing) E-map B-map reconstruction Delensed B-map subtract f(E,B) Hu & Okamota Hirata& Seljak Expected B-map from lensing • The lensing potential f can be reconstructed to predict the expected B-mode from lensing • This procedure is noise limited in principle • With ~1 mK-arcmin noise (target noise level for POLAR Array deep survey), a factor • of 4 reduction in lensing B-mode contamination C. L. Kuo POLAR Array

  11. Two Surveys with the POLAR Array • The Deep Survey • 400 square degrees ; 1 mK-arcmin • Deep search of Primordial B-mode with de-lensing (4×) • Possible to reach well below r~0.01 , depending on dust foreground • The Wide Survey • Tens of thousands of square degrees ; 6-10 mK-arcmin • Neutrino mass (~0.06 eV) • ns, Wk, dark energy from lensing and EE/TE • Precise measurements of r or nt(in the event that r is large) 1.6m 2000×2 400 (funded)

  12. POLAR-1, a technological/scientific pathfinder • Feeding 2,000 detector pairs (2.1 Fl) with a 1.6m telescope @150 GHz • 5% spillover scattered toward the cold sky (15 K) – actively cooling avoided • Twenty 4” silicon detector tiles (BICEP-2 has 4, Keck-2011 has 12) • Large-aperture infrared filters (50cm) and vacuum window (60cm) • Mitigation of beam/polarization systematics • POLAR-1 will reach the survey depth of CMBPOL in 1% of the sky Scatterer (K. Yoon) High order-corrected crossed-Dragone optics Large, flat, telecen. focal plane

  13. Antenna development R. O’Brient • Lead: JPL / Caltech • Planar antennas in BICEP2/Keck have • uniform excitation & -15dB sidelobe • Planar antenna with tapered excitation • reduces spillover power • Tapered antennas with 2.5, 2.1, 1.7 Fl being developed • Testing throughout 2011 C. L. Kuo POLAR Array

  14. POLAR-1 focal plane camera Caltech: M. Runyan BICEP-2 Focal plane, 512 detectors (fielded 2009) Keck Array = BICEP-2 x 3(5) (fielded 2010/2011) • POLAR-1 Focal plane • ~4,000 detectors (2,000 pairs) • Modular tile design • 21 tiles with POLAR-1’s crossed-Dragone • A technology pathfinder for POLAR Array • 33,600 wirebonds per receiver for POLAR? • Or, should we look for a monolithic technology? • Bump bonding hybridization ? C. L. Kuo POLAR Array

  15. POLAR-1 experiment K. Thompson C. L. Kuo POLAR Array

  16. POLAR Array Optimization • What is the appropriate aperture/resolution? • What is the appropriate sky coverage for each survey? • What is the appropriate frequency coverage? C. L. Kuo POLAR Array

  17. Aperture vs # of elements • For a given project cost – POLAR Array can have more smaller (2m) elements or fewer larger (5m) elements • Assuming the cost of the telescope scales as D2.5 power and a fixed cost per receiver, we compare these options: • These are all assumed to be crossed-Dragone systems (~2,000 TES pairs each), at 150 GHz C. L. Kuo POLAR Array

  18. Survey assumptions • 450uK∙√s ; 20,000 TES pairs @ 150 GHz with 75% yield; observing for 3×107 s (30% efficiency for 3 yrs) • Deep survey • 10% time from the 150 GHz channel • Assume that the foreground channels reach the same sensitivity • Wide survey • Foreground unlikely an issue for lensing science • “Throughput” might loose to foreground channels for the deep survey • Can be reconfigured if a tensor mode is detected C. L. Kuo POLAR Array

  19. Neutrino mass uncertainty in neutrino mass SPTPOL proposed survey Planck only s(Mn)=0.46 eV Fraction of sky to cover Kimmy Wu, 2011 C. L. Kuo POLAR Array

  20. TE/EE, or lensing? Lensing from POLAR Array TT/TE/EE from Planck uncertainty in neutrino mass TE/EE/Lensing from POLAR Array TT from Planck, also TE/EE in 1-fsky Planck only s(Mn)=0.46 eV Fraction of sky to cover Kimmy Wu, 2011 C. L. Kuo POLAR Array

  21. Neutrino mass, with degraded survey speed uncertainty in neutrino mass 2500 sq deg@ 25uK (P) (1’) Planck only s(Mn)=0.46 eV Fraction of sky to cover Kimmy Wu, 2011 C. L. Kuo POLAR Array

  22. Scalar spectral index uncertainty in scalar index ns Planck w/ H0 s(ns)=0.0072 Fraction of sky to cover Kimmy Wu, 2011 C. L. Kuo POLAR Array

  23. Spatial curvature uncertainty in curvature Wk Planck w/ H0 s(Wk)=0.0115 Fraction of sky to cover Kimmy Wu, 2011 C. L. Kuo POLAR Array

  24. Sensitivity to tensor mode WH. Teng C. L. Kuo POLAR Array

  25. Sensitivity to tensor mode WH. Teng C. L. Kuo POLAR Array

  26. Sensitivity to tensor mode WH. Teng Foreground ignored, otherwise optimal width will shift further to smaller coverage (~10-20 deg) C. L. Kuo POLAR Array

  27. If r=0.1, 1-s uncertainty on (r,nt) ? C. L. Kuo POLAR Array

  28. C. L. Kuo POLAR Array

  29. Foregrounds dust (model) synchrotron (model) At l=80-120 for r =0.01 Lines indicate different sky coverage: full-sky, |b| > 10, |b| > 30, |b| > 50, and a circular patch of radius 10 in the cleanest part of the sky Dunkley et al., 2009 CMBPOL Foreground study (1–2% dust polarization) C. L. Kuo POLAR Array

  30. Foreground Dunkley et al. 2009

  31. Remaining questions on defining the POLAR Array • Frequency distribution • Sky coverage and lowest elevation • Cross correlation with optical surveys • Technology • …. C. L. Kuo POLAR Array

  32. Conclusion • POLAR Array attempts to extract most of the science with lensing fro the ground (speed ~ 10% of CMBPOL) • Inflation energy scale (r<0.01) • Neutrino mass (∑mn<0.06 eV) • Significant improvements over Planck on spatial curvature, dark energy, spectral index • POLAR-1, a pathfinder for POLAR Array is under construction – first light in 2012/13 C. L. Kuo POLAR Array

  33. Thank you ! The South Pole Station; 2015? Image: C. Sheehy & K. Thompson The POLAR Array: * array of multiple mid-size reflectors for CMB polarization * (a few) arcminte resolution * multi-frequency (distribution TBD) * 10% the survey speed of CMBPOL * ~ 1.2 kW power, 0.1 TB/day data per element

  34. Backup slides

  35. Neutrino & the LSS Tegmark 2005 neutrino mass @ 1eV structures are damped by 2×

  36. B-mode is forbidden for density perturbations (Seljak& Zaldarriaga, 1997; Kamionkowski et al., 1997) point source observer e- for an arbitrary circle on the sky

  37. Lensing can generate B-mode (Zaldarriaga & Seljak, 1999) point source observer e- for an arbitrary circle on the sky

  38. B-mode theorem • Polarization fields can be linearly decomposed to E and B mode • Linear, scalar perturbation cannot generate B-mode polarizations • No cosmic variance (Seljak & Zaldarriaga; Kamionkowski et al, 1997) E B

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