William Jones

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William Jones Princeton University for the Spider
Collaboration The Path to CMBpol June 31, 2009
Suborbital Polarimeter for Inflation Dust and the
Epoch of Reionization
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Spider A Balloon Borne CMB Polarimeter
Suborbital Polarimeter for Inflation Dust and the
Epoch of Reionization

• Long duration (30 day cryogenic hold time)
  balloon borne polarimeter
• Surveys 60 of the sky each day of the flight,
  with 0.5 degree resolution
• Broad frequency coverage to aid in foreground
  separation
• Will extract nearly all the information from the
  CMB E-modes
• Will probe B-modes on scales where lensing does
  not dominate
• Technical Pathfinder solutions appropriate for
  a space mission

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Carbon Fiber Gondola
Six single freq. telescopes
30 day, 1850 lb, 4K / 1.4 K cryostat

• Attitude Control
• flywheel
• magnetometer
• rate gyros
• sun sensor

• Pointing Reconstruction
• 2 pointed cameras
• boresight camera
• rate gyros

• Flight Computers/ACS
• 1 TB for turnaround
• 5 TB for LDB

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Gondola and Sunshields
4600 lb Science Mass
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Spider Instrument Insert
Cryogenic Stepped HWP (not shown)
AR-coated HDPE lenses
4K Aperture Stop
Superconducting shield (array and squids inside)
Carbon Fiber Truss
Squid series arrays
High efficiency closed-cycle cooler
2-layer high µ magnetic shield (not shown)
Marc Runyan Bill Jones
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Spider Fabrication and Integration
lightweight / low cost mechanical and thermal
truss structure
cryogenic half waveplate assembly (single plate
sapphire)
John Ruhl
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Spider Fabrication and Integration

• Sub-Kelvin Stage
• Graphite standoffs for rapid cooldown
• Passive thermal lowpass filter
• G-10 backed niobium shield

• Focal Plane Assembly
• Niobium backshort/shield
• 300 mK array enclosure
• Copper thermalizing plate

• High efficiency sub-K cooler
• 10 STP Liters of 3He
• 556 J applied (500J to 4K, 50J to 1.4K)
• Cooling capacity gt3.8 J
• Cooling Power 0.2 mK/µW _at_ 280 mK

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Spider Fabrication and Integration

• Sub-Kelvin Stage
• Graphite standoffs for rapid cooldown
• Passive thermal lowpass filter
• G-10 backed niobium shield

• Focal Plane Assembly
• Niobium backshort/shield
• 300 mK array enclosure
• Copper thermalizing plate

• High efficiency sub-K cooler
• 10 STP Liters of 3He
• 556 J applied (500J to 4K, 50J to 1.4K)
• Cooling capacity gt3.8 J
• Cooling Power 0.2 mK/µW _at_ 280 mK

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Planar Array Focal Plane Performance

• Excellent efficiency
• Good uniformity of device parameters
• High device yield

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Planar Array Focal Plane Performance

• Excellent efficiency
• Good uniformity of device parameters
• High device yield

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Spider Flight Cryostat

• Aluminum construction
• 1100 L LHe
• Seven instrument bays
• 35 day holdtime
• 120 / 20 / 4 / 1.4K stages
• 1850 lb dry weight

Deployable window Minimizes the amplitude of
spurious polarization skyward of waveplate
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Spider Flight Cryostat

• Cold right now
• Seems to work as expected

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• Spiders Flight Schedule
• Sep 2010 Alice Springs 5-day turnaround flight
• Achieve E-mode science goals
• Establish competitive limits on scalar to tensor
  ratio
• 20 day LDB flight the following season (Raccoon
  or Antarctic LDB)
• Characterize the B-mode spectrum
• Map the Galactic polarized emission

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Spider Turnaround Flight
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Spider Long Duration Balloon Flight
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Spiders Scan Strategy

• 36 deg/s gondola spin rate at night
• HWP stepped 22.5 degrees once per day
• paired telescopes clocked by 45 deg
• pointed sinusoidal scanning during the day

Galactic Coordinates
Celestial Coordinates
Note coverage shown for Austral Summer launch
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Spider Turnaround FlightExperiment Details
Angular resolution 60 / 42 Arcminutes
Frequency Coverage 96 / 145 GHz
Sky Coverage 60 24800 deg2
Multipole Coverage 8 - 300 -
Polarization Modulation? Stepped HWP -
Types of Detectors Antenna coupled TES (tMUX)
Location Balloon -
Instrument NET 4 / 3 ?K s1/2
Limit on r lt 0.15 3 ?
Status September 2010 -
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Spider LDB FlightExperiment Details
Angular resolution 60 / 40 / 30 Arcminutes
Frequency Coverage 96 / 145 / 220 GHz
Sky Coverage 60 24800 deg2
Multipole Coverage 8 - 300 -
Polarization Modulation? Stepped HWP -
Types of Detectors Antenna coupled TES -
Location Balloon -
Instrument NET 4 / 3 / 9 ?K s1/2
Limit on r lt 0.05 5 ?
Status (Sep/Dec) 2011 -
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Systematic Requirements Known Unknowns

• Method
• Choose your poisons
• Introduce them to your timestream
• See what couples to the Q/U maps
• Derive impact on the BB spectrum

MacTavish et al., The Astrophysical Journal
(2008) Volume 689 Issue 2 Pages 655-665
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Systematic Requirements Known Unknowns
(poisons)
No Problem!
MacTavish et al., The Astrophysical Journal
(2008) Volume 689 Issue 2 Pages 655-665
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Systematic Requirements Unknown Unknowns

• Magnetic Shielding Requirements
• Non-idealities in the optical system
• HWP spectral transmission
• limited common mode rejection

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Foreground Mitigation
we pack them as closely as possible
Watch for Veneziani et al
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Spiders Science Goals

• Test Flight
• E-mode science (preemptively) complementary to
  Planck
• Competitive Limit on r (lt0.15)
• Galactic dust polarization (100/150 GHz)
• Long Duration Flight
• Limit on r (lt0.05)
• T/S limit extremely complementary to Planck
• (regardless of HFIs performance on large scales)
  

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Large Scale E-modes

• Mortenson Hu arxiv0705.1132
• Colombo Pierapoli arxiv0804.0278
• Lewis, Weller Battye astro-ph0606552
• Mortenson Hu astro-ph0607652 (patchy
  reionization)
• Zaldarriaga, et al. arxiv0811.3918 (sections
  34)
• Li Zhang arxiv0810.0403 (CPT violations)
• Cabella, Natoli Silk arxiv0705.0810

Dark Matter

• Peebles, Seager, Hu ApJ 539, 2000
• Padmanabhan Finkbeiner astro/ph0503486
• Mapelli, Ferrara, Pierapoli astro/ph0603237

Probes of Inflation

• Baumann, et al. arxiv 0811.3919
• Mortenson Hu arxiv 0710.4162

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Science from Turnaround Flight

• Readily achievable E-mode science goals
• measurement of tau nearly cosmic variance
  limited
• break parameter degeneracies / probe
  cosmological models
• first direct probe of recombination history
• enable limits on inflationary parameters

• Competitive BB measurement
• limit r 0.15 (ie, do better than TTlow z)

• Accurate polarimetry of Galactic emission
• high fidelity reconstruction of emission
  (minimal spatial filtering)
• improved understanding of emission mechanisms
  and magnetic fields
• polarized sources provide important calibration
  data for Planck

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Science from Turnaround Flight
The marginalized likelihood for the optical depth
to reionization as measured by WMAP 8-yr (beige)
and by Spiders turnaround flight. The factor of
2 improvement on the measurement of the optical
depth to reionization lifts much of the
degeneracy that limits our knowledge of the
scalar index as well as that of the standard
cosmological parameters.
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B-mode Science from LDB flight
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B-mode Science from LDB flight
LDB McMurdo
LDB Alice Springs
Turnaround Alice Springs
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Current State-of-the-Art
r - ?
Carrie MacTavish, Daniel ODea
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WMAP and Planck
r - ?
r0.05
r0.10
Carrie MacTavish, Daniel ODea
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WMAP and Planck
r - ?
r0.05
r0.10
Carrie MacTavish, Daniel ODea
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WMAP and Planck
r - ns
r0.05
r0.10
Carrie MacTavish, Daniel ODea
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Pixel Based Parameter Likelihoods
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Marzieh Farhang
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