Feedhorn-Coupled Polarimeters for the Next Generation of CMB Polarization Experiments

Transcription

1 Feedhorn-Coupled Polarimeters for the Next Generation of CMB Polarization Experiments Jason Austermann NIST-Boulder USA Moriond -- March 22 nd, 2016 Photo Credit: Jonathan Ward

2 Generations of Ground Based Bolometric CMB Observations GEN 0: O(1) - O(10) detectors Gen 1: O(100) O(10 3 ) Gen 2: O(10 3 ) + polarization Gen 3: O(10 4 ) + multi-chroic + polarization ACBAR Example: 2007: SPT-SZ 960 detectors Example: 2012: SPTpol ~1600 detectors All detectos roughly background-limited, therefore: More Detectors Added capability (polarization, spectral coverage) Control of systematics 2016

3 Generations of Ground Based Bolometric CMB Observations GEN 0: O(1) - O(10) detectors Gen 1: O(100) O(10 3 ) Gen 2: O(10 3 ) + polarization Gen 3: O(10 4 ) + multi-chroic + polarization ACBAR 2007: SPT-SZ 960 detectors Stage-4: Coordinated Community effort: O(500,000) detectors 2012: SPTpol ~1600 detectors 2016 Vision: Early 2020 s

4 NIST CMB Technology Development Detectors Feedhorns Readout TES and MKIDs Stacked Si platelet array SQUIDS: TDM, FDM, µwave-mux Heritage includes ACTPol, SPTpol, ABS (many more for readout) Ongoing/future: BLAST-Pol, Advanced ACTPol, Mustang-2, SPIDER, Litebird, TolTEC

5 Polarimeter Development NIST J. Austermann J. A. Beall D. Becker S. M. Duff J. Gao A. Grigorian G.C. Hilton J. Hubmayr C. McKenney O. Quaranta J. Ullom J. Van Lanen M. Vissers UC Berkeley E.M. George N. Harrington W.L. Holtzapfel Stanford H.M. Cho D. Li K. Irwin K.W. Yoon UMich R. Datta J. McMahon C. Munson UPenn M.D. Devlin M. Lungu B.L. Schmitt J. Ward Case Western J. Ruhl Cornell S. Henderson B.J. Koopman M.D. Niemack Princeton S. Choi K. Crowley E. Grace P. Ho L. Page C. Pappas L. Parker S. Simon S.T. Staggs U of Colorado W. Everett N. Halverson J.T. Sayre NASA Goddard H. Moseley E. Wollack U Chicago L. Bleem J. Carlstrom J. W. Henning T. Natoli Johns Hopkins J. Appel T. Essinger-Hileman ANL C.L. Chang U Toronto L. Newburgh FermiLab B. A. Benson

6 Measurement Summary Figure courtesy of Lyman Page

7 Looking to the future

8 Looking to the future Raw Sensitivity: More Detectors More Bandwidth

9 Looking to the future Raw Sensitivity: More Detectors More Bandwidth Spatial Resolution: Lensing B-modes De-Lensing

10 Looking to the future Raw Sensitivity: More Detectors More Bandwidth Spatial Resolution: Lensing B-modes De-Lensing Spectral Resolution: Separate foregrounds & CMB BK/Planck Joint Analysis ( v2)

11 Looking to the future Raw Sensitivity: More Detectors More Bandwidth Spatial Resolution: Lensing B-modes De-Lensing Spectral Resolution: Separate foregrounds & CMB Systematic Control: Beams, sidelobes, crosstalk, etc

12 Silicon Feedhorn-Coupled Arrays Feedhorn Stack Waveguide Interface Detector Array Quarter-Wave Backshort Yoon et al. AIP 2009 Hubmayr et al. JLTP 2012

13 Silicon Feedhorn-Coupled Arrays Yoon et al. AIP 2009 Hubmayr et al. JLTP 2012

14 Silicon Feedhorn-Coupled Arrays corrugation profile Yoon et al. AIP 2009 Hubmayr et al. JLTP 2012

15 Silicon Feedhorn-Coupled Arrays Why Si Platelet Feedhorns? Convenient & Flexible Design: Creates room for detectors/wiring CTE matched to Si detector wafer Planar interface (e.g. filtering) Flexible optical design for matching telescope Frequency Scalable Yoon et al. AIP 2009 Hubmayr et al. JLTP 2012 Low Systematics Near Gaussian beams Symmetric beams (inc. polarization) Micromachining results in nearly identical horns No AR coating required Waveguide high-pass & Natural RF shielding

16 Silicon Feedhorn-Coupled Arrays Hubmayr et al. JLTP 2012

17 Silicon Feedhorn-Coupled Arrays

18 Silicon Feedhorn-Coupled Arrays Yoon et al. AIP 2009 Hubmayr et al. JLTP 2012

19 Multichroic CMB polarimeters 7mm McMahon et al. JLTP (2011) Four TES per spatial pixel: two frequency bands, X/Y polarization per band

20 Multichroic CMB polarimeters 7mm McMahon et al. JLTP (2011) Four TES per spatial pixel: two frequency bands, X/Y polarization per band

21 Multichroic CMB polarimeters 7mm McMahon et al. JLTP (2011) Four TES per spatial pixel: two frequency bands, X/Y polarization per band

22 Multi-Chroic Pixels Why? 90/150 GHz Pixel sensitivity Focal plane efficiency Simple and compact design 220/350 GHz

23 Response Deployed 90/150 GHz multichroic array Installed on ACTPol early 2015 Array sensitivity significantly improved 255 spatial pixels 1020 TES 85% end-to-end yield Well Matched Beams and Bands 90 GHz Beams 90 GHz band 150 GHz band 150 GHz Beams Frequency (GHz)

24 Deployed 90/150 GHz multichroic array 1 st light measurements of Centaurus A

25 Deployed 90/150 GHz multichroic array

26 In Development Low Frequency ( GHz) Scaling to other frequency bands Deployed ACTPol /150 GHz Multi-Chroic Deploying Adv ACT Spring /230 GHz Multi-Chroic Space & Balloon High Frequency 280+ GHz In Development For SPIDER & LITEBIRD 3.3:1 Bandwidth

27 Fabrication Development for the next generation Efficiency Uniformity Simplicity Yield

28 150 mm ACTPol 90/150 GHz Wafer size: 75mm to 150mm diameter Advanced ACTPol 150/230 GHz More efficient use of focal plane area Simpler integration and wiring More efficient fabrication (once established)

29 15 µm Stepper Lithography based wiring old Simplifications new Microwave Cross-unders W2 W1 cross-under

30 Normalized Resistance High Uniformity: AlMn T c 150mm aluminum manganese film 140 mk 2mK D. Li et al. JLTP 2016 Temperature (mk) 2 mk peak-to-peak variation across a 150 mm diameter wafer 30

31 AlMn Tunable T c Li et al JLTP 2016

32 Loss Index SiN Dielectric: Low Loss & Uniformity Silane/Oxygen ratio Silane/Oxygen ratio Lower loss microwave loss tangent: tan δ = 8 x 10-4 ACTPol SiOx dielectric tan δ = 2.4 x 10-3 Good optical efficiency measurements Dielectric constant is more stable and uniform across arrays easier to hit passband target

33 Repeatable and well matched spectra across 150mm wafer 33

34 MKID Polarimeters Microwave Kinetic Inductance Detectors TiN/Ti multilayer absorbers Primary Advantages: Simple (single layer) Robust Naturally Multiplexable

35 MKID Polarimeters Microwave Kinetic Inductance Detectors Single Layer Design: No Crossovers Dober et al. LTD-16

36 MKID Polarimeters Microwave Kinetic Inductance Detectors BLAST-Pol 250µm prototype P > 0.5 pw TiN/Ti multilayer absorbers η opt = 75% relative to 1-1.4THz top hat band This matches HFSS coupling simulations

37 MKID Polarimeters Microwave Kinetic Inductance Detectors Response BLAST-Pol 250µm prototype Polarization response TiN/Ti multilayer absorbers Angle (deg)

38 MKID Polarimeters Microwave Kinetic Inductance Detectors Response BLAST-Pol 250µm prototype Passbands TiN/Ti multilayer absorbers Frequency (GHz) Difference due to ellipticity in waveguide from direct machining of metal prototype waveguide

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40 Microwave Readout: High Multiplexing Factors Roach-based readout MKID BLAST-Pol 250µm Array Microwave Squids: 32x MUX chip ~ 500 MKID resonators

41 Summary NIST is providing scalable polarimeter solutions covering GHz Also developing to lower frequencies Multi-chroic pixels have been successfully fielded increase per-pixel sensitivity and focal plane efficiency Rapidly maturing microwave readout towards high multiplexing factors Significant fabrication development is paving the way for the next generation of large scale arrays