Title Here
Experimental Probe of Inflationary Cosmology (EPIC)
Jamie Bock
JPL / Caltech
JPL
Peter Day
Clive Dickenson
Darren Dowell
Mark Dragovan
Todd Gaier
Krzysztof Gorski
Warren Holmes
Jeff Jewell
Bob Kinsey
Charles Lawrence
Rick LeDuc
Erik Leitch
Steven Levin
Mark Lysek
Sara MacLellan
Hien Nguyen
Ron Ross
Celeste Satter
Mike Seiffert
Hemali Vyas
Brett Williams
The EPIC Consortium
Caltech/IPAC
Charles Beichman
Sunil Golwala
Marc Kamionkowski
Andrew Lange
Tim Pearson
Anthony Readhead
Jonas Zmuidzinas
UC Berkeley/LBNL
Adrian Lee
Carl Heiles
Bill Holzapfel
Paul Richards
Helmut Spieler
Huan Tran
Martin White
Cardiff
Walter Gear
Carnegie Mellon
Jeff Peterson
U Chicago
John Carlstrom
Clem Pryke
UC Irvine
Alex Amblard
Asantha Cooray
Manoj Kaplinghat
U Colorado
Jason Glenn
U Minnesota
Shaul Hanany
Tomotake Matsumura
Michael Milligan
UC Davis
Lloyd Knox
NIST
Kent Irwin
Dartmouth
Robert Caldwell
UC San Diego
Brian Keating
Tom Renbarger
Fermilab
Scott Dodelson
IAP
Ken Ganga
Eric Hivon
IAS
Jean-Loup Puget
Nicolas Ponthieu
Stanford
Sarah Church
Swales Aerospace
Dustin Crumb
TC Technology
Terry Cafferty
USC
Aluizio Prata
Title Here
US Activities
and Opportunities
NASA funded 3 mission studies for the Einstein “Inflation Probe” in 2003
• Envisioned as $350-$500M mission, launch 2010 & every 3 years
• Since 2003 there have been some programmatic changes at NASA…
• Oral reports were given at NASA HQ this month
• Written reports are still being drafted
Task Force For CMB Research (Weiss Committee) in 2005
• Programmatic and technical roadmap to a 2018 launch for US agencies
• Two mission options described
• Sets mission guidelines: r = 0.01 is science goal
NRC panel to recommend first Beyond Einstein mission to NASA
• First Beyond Einstein mission funding is to turn on 2008-9
• CMBPOL, Con-X, LISA, JDEM (aka SNAP), and Black Hole Finder
• Recommendation based on “scientific merit and technical readiness”
• NRC also to recommend areas for technology funding for next 4 BE missions
• Three CMBPOL study teams will organize a single presentation to NRC
MIDEX call expected in October 2007
• Expected cap $220 - $260M including launch vehicle and 30 % cost reserve
• Launch 2013 - 2015
• International participation in MIDEX’s limited in the past (~30 %)
• Unknown if NASA would change the rules for this AO... probably unlikely
Here
Two MissionTitle
Scenarios
for CMBPOL
Gravitational-Wave BB Polarization
Clear Justification for Space Mission
- Large angular scales required
T
Modest Mission Parameters
- Enough sensitivity to hit lensing limit
- Angular resolution to probe ℓ = 100
- Broad frequency coverage
Scalars
Dust
High-ℓ Science
Lensing BB signal
- How deeply can we remove lensing?
- Will foregrounds limit us first?
- How much more science do we get?
- Do we need to go to space for this?
EE power spectrum to cosmic variance
- Much will be done from the ground
E
B
B
Synch
IGWs
Title Here
EPIC is a Scan-Imaging
Polarimeter
Scan detectors across sky to build CMB map
Simple technique. Established history in CMB.
Scaling to higher sensitivity → Only need better arrays
Adapt this technique for precision polarimetry
Two mission concepts*
Low Cost: High-TRL, low-resolution, sufficient capability
Comprehensive Science: Larger aperture, new arrays
*See Weiss Committee TFCR Report: astro-ph 0604101
Boomerang
BICEP
Planck
Polarbear
Maxipol
QUaD
EBEX
Spider
PAST
ACTIVE
PLANNED
FUTURE
Title Here
Orbit
55°
Moon
45°
Sun-Spacecraft Axis (~1 rph)
Sun
Earth
Why Space?
- All-Sky Coverage
- High Sensitivity
- Systematic Error Control
- Broad Frequency Coverage
SE L2
Title Here
Title Here
Scan
Strategy
55˚
Precession
(~1 rph)
1 minute
Scan Coverage
Downlink
To Earth
1 hour
Sun-Spacecraft Axis
3 minutes
45˚
Title Here
Scan
Strategy
1 Day Maps
55˚
Precession
(~1 rph)
45˚
Sun-Spacecraft Axis
Spatial Coverage
Downlink
To Earth
Angular Uniformity
More than half the sky in a single day!
Title
Here Scan Coverage
Redundant &
Uniform
N-hits (1-day)
Angular Uniformity* (6-months)
Planck
WMAP
EPIC
*<cos 2b>2 + <sin 2b>2
0
1
TitleMission
Here
EPIC Low Cost
Architecture
Liquid Helium Cryostat (450 ℓ)
Deployed
Sunshield
Six 30 cm Telescopes
30/40
60
2 x 90
135
200/300
GHz
GHz
GHz
GHz
GHz
Commercial
Spacecraft
Solar Panels
40 K
Absorbing Forebaffle
Half-Wave Plate
2 K Refracting Optics
100 K
100 mK Focal Plane Array
155 K
295 K
8m
3-Stage V-Groove Radiator
Delta 2925H 3-m
Toroidal-Beam Antenna
Title Here
Low-Cost Sunshield
Deployment Sequence
Title Here
Low-Cost Sunshield
Deployment Sequence
Title Here
Low-Cost Sunshield
Deployment Sequence
Title Here
Low-Cost Sunshield
Deployment Sequence
Title Here
Low-Cost Sunshield
Deployment Sequence
Title Here
Low-Cost Sunshield
Deployment Sequence
HereMission Architecture
Comprehensive Title
Science
40 K
Passively Cooled Mirrors
Receiver & Lenses
85 K
155 K
293 K
3-Axis S/C
Solar Panels
Gimballed Antenna
3-Stage Sunshield
Wrap-Rib Deployment
LHe Dewar
or Cryocooler
3-Stage V-Groove
Atlas V 551
20 m
TitleExisting
Here Detector Arrays
Sensitivity with
Half-Wave
Plate (2 K)
30 cm
Aperture
Stop (2 K)
NTD Ge Bolometers
Freq FWHM
#
NET/det* NET*
[GHz] [arcmin] [det’s] [mKs]
[mKs]
Planck
NET/det†
[mKs]
155
8
69
24.5
40
116
54
60
8.2
60
77
128
49
4.4
90
52
256
42
2.6
102
135
34
256
38
2.4
83
200
23
64
41
5.1
134
300
16
64
95
11.8
404
Total
830
†Goal
30
1.5
Note modest detector improvement over Planck due
to relaxed time constant specification & 2 K optics
Polyethylene
Lenses (2 K)
Planck Projected Sensitivities
Telecentric
Focus
Instrument
Technology
NET [mKs]
Value
HFI
NTD Ge
Bolometer
20.3
Design Goal
< 16.7
Measured
HEMT
68.9
Req’t
100 – 850 GHz
Focal Plane
Bolometer Array
(100 mK)
*Design Sensitivity
Absorbing
Baffle (40 K)
Sensitivity
EPIC Projected Bands and Sensitivities
LFI
30 – 70 GHz
Titlefor
Here
NTD Bolometers
Planck & Herschel
143 GHz Spider-web Bolometer
Planck/HFI focal plane (52 bolometers)
NTD Germanium
SPIRE Low-power JFETs
Herschel/SPIRE Bolometer Array
Title Here
Antenna-Coupled
Bolometers for EPIC
Measured Beam Patterns
X-polarization
Y-polarization
8 mm
Measured Spectral Response
Single Pixel – Dual Pol at 150 GHz (JPL/CIT)
High Optical
Efficiency!
Advantages
Small active volume.. 30 – 300 GHz operation
Beam collimation…... Eliminates discrete feeds
Reduced focal plane mass
Intrinsic filters…….... No discrete components
Kuo et al. SPIE 2006
TitleHigh
HereTechnology Readiness
Low-Cost Mission:
Technology
TRL
Heritage
Focal Plane Arrays (NTD Ge bolometers)
NTD thermistors and readouts
Antennas
8
4
Planck & Herschel
Wide-Field Refractor
6
BICEP
Waveplate (stepped every 24 hours)
Optical configuration
Cryogenic stepper drive
6
9
SCUBA, HERTZ, etc.
Spitzer
LHe Cryostat
9
Spitzer, ISO, Herschel
Sub-K Cooler: Single-shot ADR
9
ASTRO-E2 (single-shot)
Deployable Sunshield
4-5
TRL=9 components
Toroidal-Beam Downlink Antenna
4-5
TRL=9 components
New technologies bring enhanced capabilities…
Antenna-Coupled TES / MKID detectors
Continuously rotating waveplate
Continuous ADR
Higher sensitivity, less mass & power
Better beam control
Less mass, no interruptions
…but we have the technology to do this mission today
Here Arrays
TES Title
Bolometer
SQUID Multiplexing
Advantages
Multiplexing……. Larger array formats
Higher sensitivity
Fewer wires to 100 mK
Low cryogenic power disp.
Faster response... Useful for larger aperture
Freq. Domain (UCB/LBNL)
SCUBA2 Focal Plane (10,000 TES Bolometers)
Time Domain (NIST)
Antenna-Coupled TES Bolometers (UCB/LBNL)
Title Here
Low-Cost Mission
Focal Plane Options
Input Assumptions
Fractional bandwidth Dn/n = 30 %
Focal plane temperature = 100 mK
Waveplate temperature = 20 K, with 2 % coupling
Psat/Q = 5 for TES bolometers
Optical efficiency h = 40 %
Optics temperature = 2 K, with 10 % coupling
Baffle at 40 K with 0.3 % coupling (measured)
G0 = 10 Q / T0 for NTD bolometers
NTD Bolometer Option
30
40
155
116
8
54
60
77
128
70
6.2
18.9
110
49
4.4
9.5
56
90
135
200
300
Total7
52
34
23
16
256
256
64
64
830
59
53
58
135
3.7
3.3
7.2
16.7
2.1
11.3
10.2
22.1
51.4
6.5
67
61
130
310
39
42
38
41
95
2.6
2.4
5.1
11.8
1.5
5.6
5.1
11.0
25.7
3.3
34
30
66
150
19
dTpix6
[nK]
630
210
TES Bolometer Option
Required Sensitivity1
NET4 [mKs]
dT-q5
[mK ′]
bolo
band
87
30.8
66.7
77
10.4
22.7
66
5.8
12.7
Design Sensitivity2
NET4 [mKs]
dT-q5
dTpix6
[mK ′]
[nK]
bolo
band
62
22
33.4
280
54
7.4
11.3
95
47
4.1
6.3
53
Freq
[GHz]
qFWHM
[′]
Nbol3
[#]
30
40
60
155
116
77
8
54
128
90
52
512
59
2.6
5.6
47
41
1.8
2.8
24
135
200
300
Total7
34
23
16
512
576
576
2366
59
72
145
2.6
3.0
6.0
1.5
5.7
6.5
13.0
3.2
48
55
110
27
42
51
100
1.9
2.1
4.2
1.0
2.8
3.2
6.5
1.6
24
27
55
13
dTpix6
[nK]
560
190
107
2Calculated
Nbol3
[#]
with 2 noise margin in a 1-year mission
sensitivity in 2-year design life
3Two bolometers per focal plane pixel
4Sensitivity of one bolometer in a focal plane pixel
5Sensitiivity dT in a pixel q
FWHM x qFWHM times qFWHM
6Sensitivity dT in a 120′ x 120′ pixel
7Combining all bands together
Design Sensitivity2
NET4 [mKs]
dT-q5
dTpix6
[mK ′]
[nK]
bolo
band
69
24.5
53.1
315
60
8.2
17.7
105
qFWHM
[′]
1Sensitivity
Required Sensitivity1
NET4 [mKs]
dT-q5
[mK ′]
bolo
band
98
34.6
106
85
11.5
35.4
Freq
[GHz]
Here
SystematicTitle
Error
Mitigation Strategy
Instrument Design Goal
Suppress raw systematic effect
below statistical noise level
Systematic Effect
Main Beam
Effects
DBeamsize
DGain
DBeam Offset
DEllipticity
Pol. Beam Rot’n
Polarized Sidelobes
Design Goal
1e-4
8e-5
5e-5
1e-3
3e-4
1 nKrms
Instrument Requirement
Suppress systematic errors
below r = 0.01 after correction
Mitigations
Heritage
• Refracting telescope
BICEP†
• Waveplate before telescope
• Scan crossings & CMB dipole
• Refractor + baffle
• Drift-scanned NTD bolometers
1/f Noise
16 mHz
• Or TES + modulator
• Scan crossings
Scan-Synch Signals
Optics Temp. Stability
Focal Plane
Temp. Stability
1 nKrms
10 mKrms s/s
300 mK/Hz
3 nKrms s/s
150 nK/Hz
• Scan redundancy
SPIDER‡
---
BICEP*
BOOMERANG*
EBEX/SPIDER/
POLARBEAR‡
-----
• Dual analyzers
Planck*
• Temperature monitoring &
control of all critical stages
Planck*
* = Already demonstrated to EPIC requirement
† = Proof of operation but needs improvement
‡ = Planned demonstration to EPIC requirement
Here
Wide-FieldTitle
Refracting
Optics
• Wide unaberrated FOV
• Excellent main beams
• Telecentric focus
• Waveplate = first optic
• Ultra-low sidelobes
• Field tested in BICEP
BICEP
Here
Wide-FieldTitle
Refracting
Optics
BICEP
Freq Band
[GHz]
FWHM
[arcmin]
FOV*
[deg]
30 / 40
155 / 116
28
60
90
135
200 / 300
77
52
34
23 / 16
25
22
19
17
*Strehl ratio > 0.95
Title Here
Polarization Systematics:
Main Beams
Main Beam Instrumental Polarization Effects
Calculation
- Difference PSB beam pairs
- Parameterize main beam effects
- Convolve w/ scan pattern
- Calculate resulting power spectrum
Differential Gain, Rotation
Differential FWHM
Caveats
- Calculation is conservative → single pixel
- We can always apply post facto correction
- Waveplate eliminates these effects
Differential Beam Offset
Differential Ellipticity
Title Here
Main Beam Systematic
Errors - Requirement
Title Here Errors - Goal
Main Beam Systematic
Here
Main BeamTitle
Properties
at 135 GHz
Systematic
Goal*
Req’t*
Calc†
Meas‡
D Gain
(g1-g2)/g
8e-5
3e-4
2e-4
< 5e-3
D Beam Size
(s1-s2)/s
1e-4
3e-4
1e-4
< 2e-3
D Beam Offset
Dq/2s
5e-5
2e-4
4e-6
6e-3
D Ellipticity
(e1-e2)/2
1e-3
3e-3
1e-4
< 1e-3
Pol. Rotation
Dq/2p
3e-4
1e-3
5e-6
8e-4
*Goal:
**Req’t:
†Calc:
‡Meas:
Performance at FOV Center
Suppress effect without correction below noise
Suppress effect with correction below r = 0.01
Worst performance over the FOV at 135 GHz
Median value measured in BICEP receiver
PSF
Performance at FOV Edge
Difference Beam
PSF
Difference Beam
Title
HereOffsets in BICEP
Measured D
Beam
Title Here
Far-Sidelobe
Performance
BICEP Measurements
Sky at 100 GHz
1e5
1e4
1e3
100
10
1 mK
Sidelobe Map at 100 GHz
100
~ 20% polarized
30
10
3nK
Levels below 3 nK for most of the sky!
HereWe Know Today
ForegroundsTitle
- What
Input Sky Model
Sensitivity per 14′ Pixel
EPIC
WMAP-8
Planck
Spectrum
(I nb)
Amplitude
(Stokes I)
Pol.
fraction
b=0
70mK
1%
Synchrotron
b=-3.0
40mK @ 23GHz
10%
Free-free
b=-2.15
20mK @ 23GHz
1%
FDS model 8
10mK @ 94GHz
(b~+1.7)
5%
Spinning Dust DL98 (WNM) 50mK @ 23GHz
2%
Component
CMB
Thermal Dust
2. Multi-band Removal
1. Input Sky Model
• All components we
know about today
• Fit only synch & thermal dust
• Fit components spectrally
• Let indicies float spatially
Eriksen et al. 2006
Resulting Sensitivity After Subtraction
Case
3. Results
• Removal gives a modest sensitivity loss
• Better sensitivity → better subtraction (model is linear)
4. Conclusion: FGs Look Manageable!
• Preliminary. We might find a new component tomorrow
• We don’t know where a linear model fails
Required Sens.
Design Sens.
No foregrounds
35
12
bs and bd fixed
50
17
bs and bd fitted
in 30˚ patches
55
18
bs and bd fitted
in 30˚ patches
70
22
nKCMB in 2˚ pixels
Title Here
Conclusions
Exciting CMB science in the post-Planck era
§ Clear role for gravitational-wave polarization science in space
§ High-ℓ science compelling but need for space is less robust
Imaging polarimeter approach
§ Technically and scientifically feasible
§ Simple technique, established history.
§ Simple scaling to higher sensitivity: improve the focal plane.
§ Design in extensive control of systematics from the beginning
§ Low-Cost option → meets Weiss Committee guidelines for GW science
§ Comprehensive Science option → more capable, more science, more $
Foregrounds
§ What we know today about polarized foreground shows they can
be subtracted below r = 0.01
Technologies
§ We can build a very capable mission today with existing technology
§ New technologies will improve the mission & reduce technical risk