Download ET: Einstein Telescope

ET: Einstein Telescope
Michele Punturo
INFN Perugia
On behalf of the ET design study team
ILIAS General meeting, Jaca Feb 2008
1
Evolution of the current GW detectors
• Current Gravitational Wave interferometric detectors
have a well defined evolution line in the next 5-7
years
– LIGO just completed its S5 scientific run
– Virgo completed in October 07 its first long scientific run
in parallel with LIGO
• Both the detectors are in upgrade/commissioning mode to
implement their 1.5 generation upgrade step (Virgo+, enhanced
LIGO)
– GEO is covering (“astrowatch” mode) the down time of
LIGO and Virgo in collaboration with the resonant bar
detectors
• … see G.Losurdo Talk
ILIAS General meeting, Jaca Feb 2008
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h (Hz-1/2)
1st generation GW detectors sensitivities
-18
10
1st generation detectors
Pulsars
hmax – 1 yr integration
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10
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LIGO
Credit: P.Rapagnani
Virgo
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BH-BH Merger
Oscillations
@ 100 Mpc
GEO
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10
Core Collapse
@ 10 Mpc
QNM from BH Collisions,
100 - 10 Msun, 150 Mpc
QNM from BH Collisions,
1000 - 100 Msun, z=1
Resonant
antennas
BH-BH Inspiral, 100 Mpc
-22
NS-NS Merger
Oscillations
@ 100 Mpc
10
BH-BH Inspiral,
z = 0.4
NS, e=10-6 , 10 kpc
-23
10
NS-NS Inspiral, 300 Mpc
-24
10– May 2, 2006
ESO
1
10
ILIAS General meeting, JacaG.Losurdo
Feb 2008 – INFN Firenze
100
3
1000
3
Hz
4
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“1.5 generation” sensitivities
Laser amplifier
Higher finesse, lower mirror TN
ILIAS General meeting, Jaca Feb 2008
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Advanced detectors
• Enhanced detectors are a step toward the realization of the 2nd
generation detectors (“advanced”)
– Also GEO will participate to the network of enhanced detectors with an
upgraded version, “specialized” in the high frequency regime thanks
(mainly) to the signal recycling technology
• GEO HF
– They are based on “small” changes of the current detectors with available
technologies that anticipate the next step
• Advanced detectors will be online in the >2013 timeslot
– They will be based on known technologies currently under preliminary
engineering phase
•
•
•
•
High power laser (~200W) and compliant optics
Lower thermal noise mirrors (substrates and coatings)
Lower thermal noise suspensions (FS monolithic suspensions)
Better seismic isolation
– Active filtering in LIGO
– Focused improvements of the Virgo Super-Attenuator
• Signal recycling
ILIAS General meeting, Jaca Feb 2008
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Credit:
Detection
progresses
Richard Powell,
Beverly Berger.
From LIGO presentation
G050121
NS-NS (1.4MS):
13  15/50  120/170 Mpc
10
-18
h(f) [1/sqrt(Hz)]
st
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1 generation:
Virgo
LIGO
1.5 generation:
Virgo+
eLIGO
nd
2 generation
advVirgo
advLIGO
10
100
NS-NS
1000
Frequency [Hz]
10000
3rd generation detectors
• Second generation detectors:
– Will permit the detection of Gravitational Waves (GW)
– Will open the era of the GW astronomy
– Will be the “core business” of the next decade in
experimental GW research
• But can we look beyond?
– Precision GW astronomy needs high SNR to determine
the parameters of the astrophysical process
– Interesting phenomena involves massive bodies that
requires low frequency sensitivity in GW detectors
– We need to think to 3rd generation GW detectors
ILIAS General meeting, Jaca Feb 2008
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Objectives of a 3 rd generation GW detectors
From detection and initial GW astronomy to precision GW astronomy
• Fundamental Physics: Test general relativity in the strongly non-linear
regime
– Initial and advanced detectors won’t have the sensitivity required to test
strong field GR (too low SNR)
• Most tests are currently quoted in the context of LISA, but in a different frequency range
– We need to have good enough SNR for rare BBH mergers which will
enable strong-field test of GR
• Black hole physics:
•
– What is the end state of a gravitational collapse?
Astrophysics: Take a census of binary neutron stars in the high red-shift
Universe
– Adv VIRGO/LIGO might confirm BNS mergers, possibly provide links to g-ray
bursts
– 3rd generation GW detectors could do much more: see different classes of
sources (NS-NS, NS-BH) and contribute to resolve the enigma in the variety of
g-ray bursts
ILIAS General meeting, Jaca Feb 2008
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How to arrive to an European 3rd
generation GW Observatory?
• Long preparatory path, already started:
– ILIAS played a determinant role:
• ILIAS-GW-WP3 realized the correct environment where to discuss, at
European level, the evolution of the current detectors and where to merge
the efforts addressed to the proposition of a 3rd generation GW
observatory
– It supported the meetings, the workshops and the preliminary studies
– All the ET proposal writing meetings have been supported by WP3
– WP3 has been also the core of the new WG6 (GW) in the ASPERA road-mapping
activity
• ILIAS-JRA3 (STREGA) partially supported R&D activities in thermal noise
issues for 3rd generation GW detectors
– European Science Foundation supported an exploratory workshop
(Perugia, Sept 2005) that has been a milestone in the definition of
the strategy for the proposal of a new Observatory
– FP7 Design Study has been the perfect environment where to
synthesize our ideas in a proposal and compete with other excellent
proposals
ILIAS General meeting, Jaca Feb 2008
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ET
• ET: Einstein Telescope
– An European 3rd Generation Gravitational Wave
Observatory
• Conceptual design study proposed at the May
2007 FP7 call
– Capacities
• Research Infrastructures
– Collaborative projects
ILIAS General meeting, Jaca Feb 2008
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ET: Participants
Participant no.
Participant organization name
Country
1
European Gravitational Observatory
Italy-France
2
Istituto Nazionale di Fisica Nucleare
Italy
3
Max-Planck-Gesellschaft zur Förderung der
Wissenschaften e.V., acting through MaxPlanck-Institut für Gravitationsphysik
Germany
4
Centre National de la Recherche Scientifique
France
5
University of Birmingham
United Kingdom
6
University of Glasgow
United Kingdom
7
NIKHEF
The Netherlands
8
Cardiff University
United Kingdom
ILIAS General meeting, Jaca Feb 2008
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ET: Status of the project
• The proposal passed the first selection and now
we are in an advanced negotiation phase
• We agreed a budget reduction to 3M€ for
38Months of activity
– Main costs: man power and travels
• Description of Work document accepted by the
European Officer
– We are submitting the signed documents to prepare
the Grant Agreement
– Consortium Agreement under final definition
ILIAS General meeting, Jaca Feb 2008
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Project
Coordinator
Project organization
Scientific
Coordinator
Secretary
WP1
coordinator:
Infrastructures
WP2
coordinator:
suspensions
WP3
coordinator:
Topology
Task
responsible
Task
reponsible
Task
responsible
Task
responsible
Task
responsible
Task
responsible
WP4
coordinator:
Astrophysics
Task
responsible
Task
responsible
ET Project
WP5:
Management
Executive
board
Governing
Council
Institutions
Science
Team
Information fluxes
Scientific
community
• Project organization driven by the “Physics”:
– 4 working groups are devoted to the major
technical and scientific issues
– Let see the main technical aspects:
ILIAS General meeting, Jaca Feb 2008
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3 main noise sources
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1st generation
2nd generation
3rd generation
Thermal Noise
1
10
100
ILIAS General meeting, Jaca Feb 2008
1000
10000
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Thermal Noise
• Long interferometer arms
3 main noise sources
• Cryogenic optics
1st generation
2nd generation
3rd generation
• Large beams, large optics
-19
10
• Improved coatings
• Non-gaussian beams
10
-20
10
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10
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10
-23
Thermal Noise
•Long interferometer arms
• Cryogenic optics
•Large beams, large optics
10
-24
10
-25
• Non-gaussian beams
2nd generation
10km
• Improved coatings
1
10
100
ILIAS General meeting, Jaca Feb 2008
1000
10000
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Cryogenic Optics
• Test masses and suspensions thermal noise reduces at low temperature:
<X2> ~ T
• Thermoelastic noise of the mirror substrates and coatings decrease: <X2> ~ α T2
– Thermal expansion rate a decreases at low temperature;
• Mechanical Q of some materials increases at low temperature
• Thermal lensing:
– Thermal conductivity increases and consequently reduces thermal gradients on the
coating;
– Refraction index variation with temperature is very small at low temperature;
(Sapphire @ 20K β = 9 × 10−8, Fused Silica @ 300K β ~ 10−6)
ILIAS General meeting, Jaca Feb 2008
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ILIAS “supported” or related activities
Silicon substrates
Mechanical loss of coated silicon cantilever
R&D activities in many
European Labs:
Glasgow, INFN
Florence & Perugia,
Jena University, …
-5
3.5x10
Coatings studies
4th mode undoped Ta2O5
4th mode, TiO2 doped Ta2O5
R&D activities in many
European Labs:
Glasgow, INFN Perugia,
LMA-Lyon, MPG
Hannover, …
-5
3.0x10
-5
2.5x10
-5
2.0x10
-5
1.5x10
-5
1.0x10
0
50
100
150
200
250
300
Temperature (K)
Cryogenic Super attenuator
R&D activities in INFN
Rome & Pisa
ILIAS General meeting, Jaca Feb 2008
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Thermal Noise
• Long interferometer arms
• Cryogenic optics
3 main noise sources
1st generation
2nd generation
3rd generation
• Large beams, large optics
-19
10
• Improved coatings
• Non-gaussian beams
10
-20
10
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10
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10
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10
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10km
10km, 20K
1
10
100
ILIAS General meeting, Jaca Feb 2008
1000
10000
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Thermal Noise
• Long interferometer arms
• Cryogenic optics
3 main noise sources
1st generation
2nd generation
3rd generation
• Large beams, large optics
-19
10
• Improved coatings
• Non-gaussian beams
10
-20
10
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10
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10
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10
-24
10
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10km, 20K, 10cm
1
10
10km, 20K
100
ILIAS General meeting, Jaca Feb 2008
1000
10000
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Non Gaussian Beams
• Thermal noise in a GW interferometric detector
could be further reduced by using “flatter”
beams:
ILIAS General meeting, Jaca Feb 2008
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Thermal Noise
• Long interferometer arms
• Cryogenic optics
3 main noise sources
1st generation
2nd generation
3rd generation
• Large beams, large optics
-19
10
• Improved coatings
• Non-gaussian beams
• Improved coatings
10
-20
10
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10
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10
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10km, 20K, 10cm
10km, 20K, 10cm, non gauss
1
10
100
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1000
10000
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3 main noise sources
Shot-19
Noise
1st generation
2nd generation
3rd generation
10
• High laser power
•(maybe
Squeezing
-20 1550nm for silicon;
10
• less
Longthermal
interferometer
lensing @
arms
25K)
10
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800kW
Shot Noise
1
10
100
ILIAS General meeting, Jaca Feb 2008
1000
3MW
10000
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3 main noise sources
Shot-19
Noise
1st generation
2nd generation
3rd generation
10
• High laser power
• Squeezing
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10
• Long interferometer arms
• Multiple
colocated
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interferometers
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800kW
3MW
3MW, 6dB
3MW, 6dB, 10km
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1
10
100
ILIAS General meeting, Jaca Feb 2008
3MW, 6dB, 10km, 3ifos
1000
10000
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Co-located interferometers
• “Old” idea still under debate
– Possible implementation: 3 detectors in a triangle
configuration
Rüdiger, ‘85
Antenna Patterns:
Credit: Cella, Vicerè
Angular response
of a standard ITF
ILIAS General meeting, Jaca Feb 2008
Angular response
of the triangle configuration
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3 main noise sources
1st generation
2nd generation
3rd generation
-19
10 • Underground operation
• Homogeneous ‚soil‘
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Seismic
1
10
100
ILIAS General meeting, Jaca Feb 2008
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10000
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Underground operations
• LISM: 20 m Fabry-Perot interferometer, R&D for
LCGT, moved from Mitaka (ground based) to
Kamioka (underground)
10 overall gain
• Seismic noise strongly reduced
10 at 4 Hz
2
3
Credit: K.Kuroda
ILIAS General meeting, Jaca Feb 2008
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Seismic Isolation Shortcut
Newtonian Noise!
ILIAS General meeting, Jaca Feb 2008
Figure: M.Lorenzini
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Credit: G. Cella
Surface waves
Newtonian
Noise
Credit: G. Cella
Compression waves
credit: G.Cella
• Surface waves give the main contribution to newtonian noise
Reduction factor
(Compression waves not included)
Surface waves die
exponentially with
depth
102 less seismic noise x 104 geometrical reduction
NN reduction of 104
@5 Hz
with a 20 m radius
cave
Cave radius [m]
106 overall reduction (far from surface)
ILIAS General meeting, Jaca Feb 2008
Credit: G.Cella
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3 main noise sources
10
-19
10
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1st generation
2nd generation
3rd generation
Ground surface
Underground
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1
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Conclusions
• The target of the four Working Groups in the ET project is to try to
transform these (and many other) ideas in a coherent conceptual
design
• It is an huge job for a restricted set of persons
• ET is an emerging facility for the whole Europe and we don’t want
to limit the contribution to the founding team/institutions
• The proposal writers created in the project structure a special body
that permits the exchange with a larger Scientific Community
• The Science Team has been considered
extremely important by the project
referee and already promoted the
Governing
Council
interest of European and extraEuropean Scientists
Institutions
• If you are interested, please, contact us
ILIAS General meeting, Jaca Feb 2008
ET Project
Executive
board
Science
Team
Scientific
community
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Comments
• ILIAS-N5 played a fundamental role in building-up
the framework where ET project is born
• ILIAS-JRA3 partially supported the technological
development needed to “think” to ET
• ET is a conceptual design, with any R&D support:
– It needs a further support from the ILIAS (-next)
community
ILIAS General meeting, Jaca Feb 2008
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Conclusions: Planning
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Virgo
Virgo+
GEO
Advanced Virgo
GEO HF
LIGO
Hanford
Livingston
Advanced LIGO
LIGO+
LISA
E.T.
Launch Transfer data
DS
PCP
ILIAS General meeting, Jaca Feb 2008
Construction Commissioning
data
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