POLARBEAR-2 SIMONS ARRAY Project

Aritoki SuzukiUniversity of California, Berkeley

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POLARBEAR Collaboration

97 collaborators, 8 countries, 20 institutions 2

POLARBEAR Project

POLARBEAR-1 on Huan Tran Telescope

• Cosmic Microwave Background (CMB) polarimetry experiment• Inflationary and lensing B-mode• Primordial magnetic field and cosmic birefringence

• POLARBEAR-1 • Observing in Atacama, Chile since January, 2012 with 1274 bolometers @ 150 GHz• Released two measurements of lensing B-mode with CMB polarization data alone

• Auto-correlation• Lensing power spectrum

• Released evidence of lensing B-mode from cross-correlation with CIB• Season 1 release: Combined 4.7 σ for lensing B-mode measurement• Season 2 and season 3 data are being analyzed 3

Simons Array

Funded Expansion(Artist’s conception)

POLARBEAR-1

• Increase number of detectors for higher sensitivity• Expand frequency coverage for foreground removal• Three telescopes (two telescopes under construction)• 7,588 bolometers per receiver, factor of 6 increase from POLARBEAR-1 receiver• Deploy first POLARBEAR-2 receiver (PB2A) in 2016 • Deploy two more POLARBEAR-2 receivers (PB2B, PB2C) in 2017

POLARBEAR-2 Receiver Frequency Plan Simons Array, Artist’s Conception

POLARBEAR-2A 95/150

POLARBEAR-2B 95/150

POLARBEAR-2C 150/220

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Huan Tran TelescopeHuan Tran TelescopePrimary Mirror

Primary baffle

CryogenicReceiver

Secondary Mirror

• Offset Gregorian telescope, high polarization fidelity and small side lobe

• 3 meter diameter primary. 3.5 arcmin @ 150 GHz

• Telescope sized for B-mode lensing and inflationary science 5

Polarization Modulation

• POLARBEAR-2 will use three plates of birefringent sapphire to achieve broadband polarization modulation performance

Primary Mirror

Primary baffle

Cryogenic Receiver

Secondary Mirror

HWP Pola

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ula

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n E

ffic

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cyFrequency [GHz]

1801601401201008060

1.0

0.9

0.8

0.7

0.6

0.5

Optimized polarization modulation efficiency for three plates of sapphire

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Receiver

• Two pulse tube coolers provide 50 Kelvin and 4 Kelvin stages to optics tube and receiver backend

• Simon-Chase helium fridge cools focal plane to 270 milli-Kelvin

• High purity aluminum (6N) strips were used to increase thermal conductivity

POLARBEAR-2 Receiver 2 meters

500 mm

Pulse tube coolers

Optics tube

Receiver backendFocal plane

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Optics

• High purity alumina ceramic infrared absorbing filter and reimaging lenses

• High thermal conductivity and less optical aberration

• Epoxy, expanded polyimide and ceramic plasma spray anti-reflection coating

• Oliver Jeong 4.2 mm & sub-mm astronomy poster session“Broadband plasma sprayed anti-reflection coating for millimeter-wave astrophysics experiments”

2 meters

500 mm

Alumina lenses (4 K) Zotefoam Window (300 K)

Metal Mesh Filter (4 K) Alumina IR Filter (50 K)

Focal Plane

Alumina lens

500 mm

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95 GHz: Angular response 150 GHz: Angular responseSpectral responseSi lenslet coupled sinuous antenna

5.346 mm

• Lenslet coupled broadband sinuous antenna

• Diplexer filter partitions signal into frequency bands

• Aluminum-manganese TES bolometer.

• 100 um pitch fully automated wire bond

Detector

1.5 mm

Detector wafer in an invar holder

130 mm

Detector wafer and wire bondsSinuous antenna and TES bolometers

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Focal Plane

• 7 Detector modules

• Detector module:

• Lenslet Array, Detector Array, Readout electronics

• Praween Siritanasak 3.2 mm-wave devices at low temperature poster session“The broadband anti-reflection coated extended hemispherical silicon lenses for Polarbear-2 experiment.”

365 mm 150 mm

150 mm

POLARBEAR-2 Focal Plane CAD

Lenslet Array

Readout Components

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Detector wafer (inside)

Detector Module Photograph

SQUID Printed Circuit Board (4 K)

Lithographed Superconducting Inductors and Capacitors (250 mK)

NbTi Cable

Readout

Current measurement through comb of superconducting resonators

• Digital Active Nulling (DAN) frequency multiplexed SQUID readout

• Lithographed superconducting resonators (x40 mux)Kaja Rotermund 3.1 Readout electronics & signal processing II Special Poster Session“Planar Lithographed Superconducting LC Resonators for Frequency-Domain Multiplexed Readout Systems”

• Custom NbTi cable for reduced inductance and thermal loading

• DAN to increase available bandwidth (PB2: 4 MHz)

• POLARBEAR-2 readout presentation Kaori Hattori 2.4 Readout electronics & signal processing I“Development of readout electronics for POLARBEAR-2 Cosmic Microwave Background experiment”Mod/Demod (ICE) Boards 11

Forecast

Simons Array combined with Planck, C-Bass, DESI BAO (3-years)

• Inflation: 𝜎 𝑟 = 0.1 = 4 ⋅ 10−3(stat), 6 ⋅ 10−3(stat + foreground cleaning)

• Sum of neutrino mass: 𝜎 Σ𝑚𝜈 = 19 meV (stat), 40 meV (stat + FC)

• Neff constrain to +/- 0.04

• Scalar tilt: 𝜎(𝑛𝑠) = 6 ∙ 10−3

• Primordial magnetic field to μ-gauss scale

POLARBEAR-2A (1 telescope, 2016):95 GHz: 3794 TESes, 5.8 µK · √s150 GHz: 3794 TESes, 5.8 µK · √s

Simons Array full configuration (3 telescopes)95 GHz: 7,588 TESes, 4.1 µK · √s150 GHz: 11,382 TESes, 3.4 µK · √s220 GHz: 3,794 TESes, 11.5 µK · √s

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(current forecast)

Expanding Frequency Coverage

• CMB and foregrounds. Synchrotron radiation and dust emission

• Ben Westbrook 2.2 Macrobolometers “Development of the Next Generation of Multi-chroic Antenna Coupled Transition Edge Sensor Detectors for CMB Polarimetry”

20 mm

40/60/90 GHz

90/150/220/280 GHz

220/280/350 GHz

Polarization Beam maps

40 60 90

90 150 220 280

220 280 35013

Summary

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Simons Array = Funded expansion for multi-chroic telescope array• 23,000 optical bolometers• POLARBEAR-2 A (95GHz and 150 GHz) in 2016 • POLARBEAR-2 B (95GHz and 150 GHz) in 2017• POLARBEAR-2 C (150 GHz and 220 GHz) in 2017 • Inflation: 𝜎 𝑟 = 0.1 = 4 ⋅ 10−3 (stat), 6 ⋅ 10−3(stat + FC)• Sum of neutrino mass: 𝜎 Σ𝑚𝜈 = 19 meV (stat), 40 meV (stat +FC)

Site upgrade for Simons Array

Thank you

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Back Up

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Sky Area

• 80 % of sky is available from Atacama site• Cross-correlation study with other surveys for better calibration and tighter constraint

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(2) Broadband Antenna

1. Anti-reflection coated silicon lenslet focuses beam to antenna

2. Sinuous antenna collects photon over wide frequency range

3. On chip RF filter (diplexer) splits signal into frequency bands

4. Superconducting TES bolometers detect signal

(3) RF Filters

(4) TES Bolometers

(1) Si Lenslets with anti-reflection coating

Photo taken by Dan Schmidt

Multi-Chroic Pixel

5.346 mm

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Detector Module

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Lenslet Array

Detector Array

LC BoardFlex Cable

Detector Module Assembly

• Silicon lenslets (φ 5.346 mm) focus light to antennas on detector wafer

• Antenna, filter, and bolometer make detection on a detector wafer

• Wire bond to make connection from detector wafer to wire bond flex cable

• Invar clamps lenslet array and detector array together

150 mm

Lenslets

Detector waferInvar holder

AN-72 Eccosorb back short

LC B

oar

ds

Seating wafer

Wire bond

Flex cable

Copper back plate

7/14/2015 20

optical signal

LC Chip

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Digital m

od

ulato

rd

em

od

ulato

rL LLL

C1 C2 C3 C40

RboloRboloRbolo Rbolo

Rbias

Lwire

Readout Schematics

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