Transcript ppt

UK contribution to B-Pol
Lucio Piccirillo
for the UK B-Pol team
Paris, 25 October 2006
The UK collaboration:
University of Manchester
Oxford University
Cambridge University
Cardiff University
Imperial College
RAL
Edinburgh
UK institutions  main involvements in WGs
Manchester:
Theory/Foreground/Instrument
Cambridge:
Theory/Foreground/Instrument
Cardiff:
Instrument
Edinburgh:
Theory
Imperial:
Theory
Oxford:
Theory/Foreground/Instrument
RAL:
Instrument
UK institutions and people (partial list):
Manchester
Oxford
Cambridge
Cardiff
Lucio Piccirillo (I)
Ghassan Yassin (I)
Stafford Withington (I)
Phil Mauskopf (I)
Giampaolo Pisano (I)
Joe Silk (T)
Anthony Lasenby (T)
Giorgio Savini (I)
Bruno Maffei (I)
Pedro Ferreira (T)
George Efstathiou (T)
Walter Gear (I)
Simon Melhuish (I)
Angela Taylor (F)
Mike Hobson (F)
Peter Ade (I)
Richard Battye (T)
Michael Jones (I)
Michael Brown (I)
Richard Davis (I)
A & P Wilkinson (I)
Paddy Leahy (F)
Rod Davies (F)
Bob Watson (I)
Neil Roddis (I)
Danielle Kettle (E&E) (I)
Mo Missous (E&E) (I)
Anthony Challinor (T)
UK institutions:
Imperial C.
Edinburgh
RAL
Andrew Jaffe (T)
Andy Taylor (T)
Brian Ellison (I)
Carlo Contaldi (T)
John Peacock
Patricia Castro (T)
Alan Heavens
B-Pol will be a satellite mission attempting the detection of
CMB (curl) B–modes polarization.
B–modes are generated by the primordial background of
gravitational waves.
Inflation (so far) is the only mechanism able to generate these
long-wavelength gravity waves (IGWs – Inflationary
Gravitational Waves)
Amplitude of IGW  V() – value of inflaton potential during
inflation
Amplitude of B-modes directly constraints the energy scale of
inflation  link cosmology – particle physics
Instrument
specifications
(parameters)
Theoretical studies
(science)
test design
Technology
Instrument
performances
(tolerances)
Prototypes
Final Instrument
testing
UK is interested in all working groups:
Science Working Group
Foreground Working Group
Instrument Working Group
UK is interested in all working groups:
Science Working Group
Foreground Working Group
Instrument Working Group
will learn more about UK contribution in
these areas the next two days
Track Record
UK led:
VSA (CAM, MAN)
QuAD (CAR) (2nd gen.)
CLOVER (CAR, CAM, MAN, OX) (3rd gen.)
Significant UK contribution: Planck LFI & HFI,
Boomerang, MAXIMA/MAXIPOL, CBI, Archeops
1st gen. CMB polarimetry: POLAR, COMPASS
RAL  biggest UK / one of European largest space science
department. Excellent mm/sub-mm wave technical expertise
and heritage
CAM, OX, Imperial, MAN etc.  strong theory groups
potential UK role in European B-Pol
1. Experience (hardware) for major state-of-the-art CMB
polarization experiments
2. Detector design, manufacturing & testing facilities in
CAM/OX/MAN/CAR. Planar devices
3. sub-K cryogenics
4. RF components (Horns, OMTs, Phase switches, etc.)
5. Software: instrument simulations, observing strategies, data
analysis pipeline, parameter estimations, etc.
UK strength in Instrument Design
• Heterodyne and bolometric interferometry, imaging
arrays
• Telescope design: physical optics simulations,
experience in mirror and mount fabrication
• Microwave components (horns, OMTs,
polarimeters)
• Superconducting planar circuits (phase switches,
filters, radial probes, finlines)
• Detector physics and fabrication (TES, KIDS, SIS)
• Integrated Low Noise Amplifiers
UK interest in the Instrument Working Group:
1. Theoretical studies of systems and sub-systems
(optics, cryogenics, antennas, detectors & read-out, etc.)
2. R&D/prototyping of key technologies
(polarimeter components, detectors, etc.)
3. Testing from prototypes to flight hardware
(optics, cryogenics, RF, etc.)
4. Level 1 data handling
Specialized manufacturing facilities in UK
1. Cambridge detector lab: superconducting devices (TES, SIS,
KIDs, SQUIDs, etc.)
2. Manchester E&E semiconductor facilities (InP, GaAs, etc.)
3. Cardiff filter lab
4. Manchester/Chase Res.: Sub-K closed-cycle sorption
coolers (3He, 3He/ 4He, 3He/ 4He/ 3He, mini-dilutors, gas
switches, etc.)
5. RAL: precision CNC machining
An example of of mm/sub-mm UK capability/facilities: RAL
1. Electroplating & electroforming (space qualified)
2. Microwave calibration loads
3. Lapping
4. Interferometer Grids
5. Micro-drilling
6. Non contact metrology
see http://www.mmt.rl.ac.uk/
Superconducting TES Detector Arrays for B-Pol
Full superconducting detector development facility available in UK: currently
being used to manufacture microstrip-coupled TES detector arrays for CLOVER.
TES development for CLOVER
97GHz Finline microstrip-coupled TES
detector for CLOVER. The device was
designed, manufactured, and tested by the
UK CLOVER consortium. Radial-probe
detectors are being developed for the shortwavelength channels. High yields with well
controlled device parameters are being
achieved. DRIE is used to achieve the Si
micromachining.
Molecular Beam Epitaxy
facility in Manchester
Specialised testing facilities in UK:
1. Man (E&E + Physics) – Agilent lab for VNA RF (up to Wband) testing – on chip and in wave-guide – room temperature
to 4K
2. Cardiff FTS lab + 90/150 mm VNA
3. 100 mK Cam/Man/Car detector test beds
4. Car/Man mm/sub-mm anechoic chambers
micro/mm-wave Agilent labs in Manchester
Summary of main experimental UK activities:
1. detector manufacturing
2. quasi optical filters
3. e.m. simulations and manufacturing of optics
4. e.m. simulations and manufacturing of RF
components (waveguide & u-strip)
5. design and realization of sub-K cryogenics
6. test beds for large format arrays
7. cryogenic test beds for mm/sub-mm components
Summary of some (not all!) relevant UK research
activities:
1. superconducting planar phase switches
2. InP HEMT polarimeter on chip
3. Finlines and radial probes
4. sorption (0.25K) and dilution (0.05K) systems
5. CEB, KIDs detector development
6. RF components (OMTs, Horns, etc.)
... and much more ...
Some final considerations:
1. Detecting B-modes will be hard – even from space
2. A complementary ground-based/balloon experiments
at the high/low frequency range might be needed on
some selected sky regions with high sensitivity and
high angular resolution
3. Sensitivity but control of systematic effects (not only
instrumental) will be a key factor  these two
requirements somehow compete with each other...
4. When the first generation B-modes experiments will
start producing data we will probably have a much
better idea (2-3 years from now?)
5. Calibration.... data analysis!?!
END
Possible B-Pol
architecture:
• one telescope per
frequency
• uses mirrors instead of
lenses
• can “hide” components
behind the large 70 GHz
primary
• re-use a lot of design
studies carried for
CLOVER
• Somehow large
cryostat (1.6 m diam.)
• might be same weight
(or lighter) than lenses
option
• mirrors can be
radiatively cooled (?)
• ... ?
• can correct XPol
because of 2 mirrors
drawing by A. Cevolani
Ultrasensitive Cold-Electron Bolometer (CEB)
Chalmers University, Leonid Kuzmin
Collaborators: Cambridge University, Oxford University, Cardiff University, IPHT, Jena
We have achieves a record sensitivity
of the Cold-Electron Bolometer (CEB):
the noise equivalent power (NEP) of
better than 10-18 W/Hz1/2 has been
measured.
Theoretical estimations:
NEP=10-19 W/Hz1/2
The CEB consisting of two SIN tunnel
junctions and a nano-absorber has
been fabricated using nano-facilities of
MC2.
A new generation of supersensitive
detectors is to understand the
mysterious nature of Dark Matter and
Dark Energy.
We participate in balloon projects
OLIMPO and CLOVER and balloon
project PILOT led by CESR (Toulouse).
We are invited to demonstrate CEB for
ESA Space project SPICA: an ultimate
NEP= 10-19 W/ Hz1/2 for spectroscopy
should be realized for this purpose.
Figure..
Strip width = 0.2 mm
Data…
I. Agulo, L. Kuzmin, and M. Tarasov, “Attowatt
Sensitivity of the Cold-Electron Bolometer”, subm.
to Appl. Phys. Lett (2006)
Cold-Electron Bolometer (CEB) with Capacitive Coupling
to the Antenna
100 nm
CLOVER path from theory to instrument manufacturing
ClOVER is a ground-based experiment
that will attempt to measure the
primordial B-mode polarization power
spectrum of the CMB for r > 0.01
covering a multipole range 20 < l < 1000.
ClOVER will:
1.
Map the Stokes parameters over around 700 deg2 of the sky
2.
Observe at 97, 150 and 225 GHz with a 10-arcmin FWHM beam
3.
Make sample-variance-limited measurements of the <TT>, <EE> and
<TE> power spectra up to multipoles l ~ 1000
4.
Measure at high significance the B-mode power spectrum due to weak
gravitational lensing
5.
Characterize the polarization properties of galactic foregrounds
Control of systematic errors
1.
Achieve the necessary raw sensitivity. Number of photons collected  number of
horns & detectors  large focal plane arrays (160 horns at 97 GHz, 256 horns at
150 GHz, 256 horns at 225 GHz)
2.
Develop experimental techniques to keep systematic errors below the statistical
errors
3.
Build from the experience in <TT>, <TE> and <EE>. <BB> power spectrum
determination has never been attempted down to the required level for a
significant detection.
4.
The <BB> signal is small, really small! r = T/S = 0.01 means that we are looking for
rms signals of the order of 30 nK.
5.
We are designing Clover to keep systematic effects at a level of 10% (3 nK.....)
6.
DASI, CBI and CAPMAP have observed from the ground <EE> to a level of 1 mK
rms. We need to do 30 times better!
7.
900 times more sensitive is achievable considering Clover number of detectors
(1184) with better intrinsic noise (about 200 mK s1/2)
Characteristic
r
l coverage
Observing (integration time)
Beamsize for all frequency bands
Survey area
Requirements
0.01
20 < l < 1000
2 (1) year
10 arcmin (or  15 arcmin)
700 deg2
Final map shape
Minimize E – B mixing
Frequency bands
97, 150, 225 GHz
Required scan/modulation type
Single detector measure
Noise limit
intrinsic NET at 97, 150, 225 GHz
Ratio of detectors at three frequency
bands
(Polarized) ground signal rejection
Polarization, az/el/pol axis
T, Q and U
Photon noise from sky  intrinsic noise
125, 195 and 619 mK sec
160 : 256 : 256
< -100 dB wrt main beam
Spillover limit at 97, 150, 225 GHz
1.4%, 2%, 3.5%
Beam ellipticity
eccentricity < 0.3
Residual cross-polarization
- 50 dB
Polarimeter efficiency
> 90%
Residual instrument polarization
< 0.03%
Additional systematic effects:
1. Polarized side-lobes (response at Galactic emission)  z-axis
rotation, polarization modulation  (dT  B) must be kept <
10-6
2. Polarization angle  (dT  B) must know angle better than a
fraction of degree
3. Sources of optical power within the field of view must be
kept constant <3 mK (assumes 10-3 difference in emissivities)
4. Dilution fridge temperature stability < 1 nK
5. Relative pointing between different horns in the same focal
plane. It has to be better than 0.1 arcsec to keep dTB below
3 nK
Very general plan:
1. Theoretical studies (mostly done) on how to build the
instrument to satisfy the requirements
2. Build a test instrument (Single-Pixel Demonstrator) to test
mostly the detectors and cold optics, cryogenics, read-out and
electronics
3. Integrate the Clover prototype (SPD + mount) and extended
tests
4. Move Clover prototype to Atacama  test site
5. Final development of the 3 instruments
Clover SPD
3 focal planes
WG polarization
rotation
Wave plate options
Single-shot miniature selfcontained dilution refrigerator.
• 3 mW cooling power at 100 mK
• Electrically operated with sorption
pumps and gas heat-switches
• No external gas-handling system
• Fast pre-cooling times
Clover optical assemblies
97 GHz
225 GHz
150 GHz
Clover on a single mount
Clover radiation shielding