polar-1 and the polar array

Chao-Lin KuoChao-Lin KuoPhysics Department & SLAC PPA, Stanford UniversityPhysics Department & SLAC PPA, Stanford University

Kavli Institute for Particle Astrophysics and CosmologyKavli Institute for Particle Astrophysics and Cosmology

POLAR-1 and the POLAR ArrayPOLAR-1 and the POLAR Array

Collaborators Collaborators StanfordStanford

Chao-Lin KuoChao-Lin Kuo Keith ThompsonKeith Thompson Ki Won Yoon Ki Won Yoon Kimmy WuKimmy Wu Sarah Church Sarah Church

Caltech/JPLCaltech/JPL Jamie Bock Jamie Bock Roger O’BrientRoger O’Brient Howard Hui Howard Hui Marc RunyanMarc Runyan Hien NguyenHien Nguyen

UBCUBC Mark HalpernMark Halpern

NISTNIST Kent IrwinKent Irwin Gene HiltonGene Hilton

HarvardHarvard John Kovac John Kovac

MinnesotaMinnesota Clem Pryke Clem Pryke

C. L. Kuo POLAR ArraySupports from NSF-OPP-MRI

The South Pole Station; 2015?

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

Image:C. Sheehy & K. Thompson

Unlensed pure E-mode

C. L. Kuo POLAR Array

Lensing field


Lensed B-mode

WH TengC. L. Kuo POLAR Array

Lensing Lensing BB-mode measurements as of April 2011 -mode measurements as of April 2011

• 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.

H. Chiang


Lensing Lensing BB-polarization is a LSS experiment-polarization is a LSS experiment Deep polarization measurements can significantly improve Deep polarization measurements can significantly improve

Planck+WFIRST/Euclid’sPlanck+WFIRST/Euclid’s constraints on {w, constraints on {w, kk, ∑m, ∑m} etc., } etc., If one assumes a prior of If one assumes a prior of

ww00= -1, w= -1, waa=0, =0, k k <10<10-4 -4 → lensing → lensing BB provides a constraint on ∑m provides a constraint on ∑m<0.04 eV <0.04 eV

This will eitherThis will either DetectDetect a neutrino mass a neutrino mass Rule out inverted hierarchyRule out inverted hierarchy

Lesgourgues and PastorPhysics Reports, 2006

alsoAstro-2010 Panel Reports


Neutrino from CosmologyNeutrino from CosmologyAbazajian et. al. 2011

(primarily for T)

It is possible to “undo” the lensing (delensing)It is possible to “undo” the lensing (delensing)

E-map B-map

(E,B)

Expected B-map from lensing

reconstructionsubtract Delensed

B-map

• The lensing potential can be reconstructed to predict the expected B-mode from lensing• This procedure is noise limited in principle• With ~1 K-arcmin noise (target noise level for POLAR Array deep survey), a factorof 4 reduction in lensing B-mode contamination

Hu & OkamotaHirata& Seljak


Two Surveys with the Two Surveys with the POLAR ArrayPOLAR Array

• The Deep Survey • 400 square degrees ; 1 K-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 K-arcmin• Neutrino mass (~0.06 eV) • ns, k, dark energy from lensing and EE/TE

• Precise measurements of r or nt (in the event that r is large)

(funded) 1.6m 2000×2 400

POLAR-1, a technological/scientific pathfinderPOLAR-1, a technological/scientific pathfinder

• Feeding 2,000 detector pairs (2.1 F) 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

High order-correctedcrossed-Dragone optics

Scatterer (K. Yoon)

Large, flat, telecen. focal plane

Antenna developmentAntenna development

• 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 F

being developed

• Testing throughout 2011

R. O’Brient


POLAR-1 focal plane camera

BICEP-2Focal 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 ?

Caltech: M. Runyan


POLAR-1 experimentPOLAR-1 experiment

K. Thompson C. L. Kuo POLAR Array

POLAR Array OptimizationPOLAR Array Optimization

• What is the appropriate aperture/resolution?What is the appropriate aperture/resolution?

• What is the appropriate sky coverage for each survey? What is the appropriate sky coverage for each survey?

• What is the appropriate frequency coverage? What is the appropriate frequency coverage?


Aperture vs # of elementsAperture vs # of elements For a given project cost – POLAR Array can have more For a given project cost – POLAR Array can have more

smaller (2m) elements or fewer larger (5m) elementssmaller (2m) elements or fewer larger (5m) elements Assuming the cost of the telescope scales as DAssuming the cost of the telescope scales as D2.52.5 power and a power and a

fixed cost per receiver, we compare these options:fixed cost per receiver, we compare these options:

These are all assumed to be crossed-Dragone systems (~2,000 These are all assumed to be crossed-Dragone systems (~2,000 TES pairs each), at 150 GHzTES pairs each), at 150 GHz

Aperture Dia. (m)

Beam (arcmin) Approx. unit cost ($m)

# of tel. w/ fixed budget

2 5 2 10

3 3.3 3.8 5

4 2.5 6.7 3

5 2 10.9 2


Survey assumptions Survey assumptions 450uK∙√s ; 20,000 TES pairs @ 150 GHz with 75% yield; 450uK∙√s ; 20,000 TES pairs @ 150 GHz with 75% yield;

observing for 3×10observing for 3×1077 s (30% efficiency for 3 yrs) s (30% efficiency for 3 yrs)

Deep surveyDeep survey

10% time from the 150 GHz channel10% time from the 150 GHz channel

Assume that the foreground channels reach the same sensitivity Assume that the foreground channels reach the same sensitivity

Wide survey Wide survey

Foreground unlikely an issue for lensing science Foreground unlikely an issue for lensing science

““Throughput” might loose to foreground channels for the deep surveyThroughput” might loose to foreground channels for the deep survey

Can be reconfigured if a tensor mode is detected Can be reconfigured if a tensor mode is detected


Neutrino massNeutrino mass

Kimmy Wu, 2011Fraction of sky to cover

uncertainty in neutrino mass

Planck only(M)=0.46 eV

SPTPOL proposed survey


TE/EE, or lensing?TE/EE, or lensing?




Lensing from POLAR ArrayTT/TE/EE from Planck

TE/EE/Lensing from POLAR ArrayTT from Planck, also TE/EE in 1-fsky





2500 sq deg@ 25uK (P) (1’)

Neutrino mass, with degraded survey speedNeutrino mass, with degraded survey speed


Scalar spectral indexScalar spectral index


uncertainty in scalar index ns

Planck w/ H0

(ns)=0.0072


Spatial curvatureSpatial curvature


uncertainty in curvaturek

Planck w/ H0

(k)=0.0115


Sensitivity to tensor modeSensitivity to tensor mode

WH. Teng


Sensitivity to tensor modeSensitivity to tensor mode

WH. Teng

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

If If rr=0.1, 1-=0.1, 1- uncertainty on ( uncertainty on (r,nr,ntt) ?) ?


Foregrounds

Dunkley et al., 2009CMBPOL Foreground study(1–2% dust polarization)

dust(model)

synchrotron(model)

At l=80-120for 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


ForegroundForeground

Dunkley et al. 2009

Remaining questions on defining the Remaining questions on defining the POLAR ArrayPOLAR Array

Frequency distribution Frequency distribution Sky coverage and lowest elevation Sky coverage and lowest elevation Cross correlation with optical surveys Cross correlation with optical surveys Technology Technology ……..


ConclusionConclusion

POLAR Array attempts to extract most of the science with POLAR Array attempts to extract most of the science with

lensing fro the ground (speed ~ 10% of CMBPOL) lensing fro the ground (speed ~ 10% of CMBPOL)

Inflation energy scale (Inflation energy scale (rr<0.01)<0.01)

Neutrino mass (∑mNeutrino mass (∑m<0.06 eV)<0.06 eV)

Significant improvements over Planck on spatial curvature, dark Significant improvements over Planck on spatial curvature, dark

energy, spectral index energy, spectral index

POLAR-1, a pathfinder for POLAR Array is under POLAR-1, a pathfinder for POLAR Array is under

construction – first light in 2012/13construction – first light in 2012/13


The South Pole Station; 2015?

Image:C. Sheehy & K. Thompson

Thank you !Thank you !

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

Backup slidesBackup slides

Neutrino & the LSSNeutrino & the LSS

Tegmark 2005

neutrino mass @ 1eV structures are damped by 2×

B-mode is B-mode is forbiddenforbidden for density perturbations for density perturbations(Seljak& Zaldarriaga, 1997; Kamionkowski et al., 1997)

e-observer

for an arbitrary circleon the sky

point source

Lensing can generate B-modeLensing can generate B-mode(Zaldarriaga & Seljak, 1999)

e-observer

for an arbitrary circleon the sky

point source

B-mode theoremB-mode theorem

Polarization fields can be linearly Polarization fields can be linearly

decomposed to E and B modedecomposed to E and B mode

Linear, scalar perturbation cannot Linear, scalar perturbation cannot

generate B-mode polarizations generate B-mode polarizations

No cosmic varianceNo cosmic variance

(Seljak & Zaldarriaga; Kamionkowski et al, (Seljak & Zaldarriaga; Kamionkowski et al,

1997)1997)

E

B

polar-1 and the polar array

Documents

kuo polar arraysupports

kuo polar arraypolar

polar array deep survey

kuo polar arraylensing

kuo polar arraytwo surveys

expected bmode

bexpected bmap

keck array