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ILIAS meeting Mallorca 2005
V. Fafone
Viviana FafoneINFN - LNF
Future plans forresonant detectors
www.lnf.infn.it/esperimenti/rog
ILIAS meeting Mallorca 2005
V. Fafone
CERN RE 5
LNF INFN
MiniGrail
Leiden
LNL INFN
ILIAS meeting Mallorca 2005
V. Fafone
• Used to improve suspension system design
• Wideband readout design
New devices and methods are now available
• Superconductive amplifier sensitivity improved by a factor of 100
• Optical and parametric readout for acoustic detectors
• Methods to develop large masses (100 ton)
• New high cross section materials
Readout systems:
FEM analysis:
Test masses:
ILIAS meeting Mallorca 2005
V. Fafone
1998
200110-20
EXPLORER
880 950
WIDENING THE BAND…
NAUTILUS
2001
AURIGA
19992003
10-20
2003
ILIAS meeting Mallorca 2005
V. Fafone
3·10-19
No veto applied
•The duty cycle is limited mainly by cryogenic operations and for most of the time is about 90%
•The apparata show constant performances.
•The data are not affected by human activity in the lab.
NAUTILUS DATA TAKINGNAUTILUS DATA TAKING DURING 2005 DURING 2005
ILIAS meeting Mallorca 2005
V. Fafone
Noise budget is well understoodNoise budget is well understood
Teff~ 2mK
h ~ 3 10-19
•Present limit from amplifier noise
reference signalPresent Status of EXPLORERPresent Status of EXPLORER
ILIAS meeting Mallorca 2005
V. Fafone
Very good agreement with noise predictions
all these noise sources will scale with temperature
one-sided Shh
Present Status of AURIGAPresent Status of AURIGA
ILIAS meeting Mallorca 2005
V. Fafone
To improve sensitivity:• We need to improve the peak spectral sensitivity
- Increase M : large and/or multimode detectors- Reduce T/Q : ultracryogenics. Low-loss materials
• We need to increase the bandwidth- Increase the coupling of the e.m. transducer - Reduce the noise temperature of the amplifier (double
SQUIDs)
ILIAS meeting Mallorca 2005
V. Fafone
Sh for NAUTILUS @ 0.1K, parametric transducer (m = 1 kg)
Teff ≈ 6 K, sensitivity < 1·10-21 /√Hz over about 50 Hz.
Sh for AURIGA @ 0.2K, capacitive transducer
M3 - R. Parodi INFN Genova
ILIAS meeting Mallorca 2005
V. Fafone
TOWARDS MORE POWERFUL AND SENSITIVE ACOUSTIC DETECTORS
ILIAS meeting Mallorca 2005
V. Fafone
“…This paper suggests the following scenario for future detector development in this field:
•In the medium-term, the realization of a spherical detector, to be proposed now to the funding agencies, •In the longer term, research toward wideband resonant detectors using Dual Detection techniques.
GWIC Scenario for future detectors in the resonant-mass field
ILIAS meeting Mallorca 2005
V. Fafone
GWIC Scenario for future detectors in the resonant-mass field
A spherical detector can make use of the state of the art readout technology, developed for the bars and for MiniGrail, profiting from a larger mass and from the omnidirectional nature of the spherical detectors. Such a detector could have a sensitivity competitive with VIRGO and LIGO in the 1 kHz region. And since it allows full sky coverage during all observation time, and determination of the source direction, it can have an important role in a coordinated coincidence search. Since the principles of operation and technology are well understood, a funding proposal could be prepared soon.
Research and development work on wideband resonant detectors using Dual Detection techniques is valuable because it offers the potential for a detector having unprecedented sensitivity in the band 1 to 7 kHz. …”
ILIAS meeting Mallorca 2005
V. Fafone
sensitivities in the 2006 - 2012 prospective
GEO
The sphere has a quality factor due to the isotropy not shown in the plot
adv LIGO/adv VIRGO
ILIAS meeting Mallorca 2005
V. Fafone
Thanks its five quadrupolar modes, equally sensitive to gravitational waves:
Properties of spherical detectors: a summary…
•Reconstruction of the metric tensor (polarization states and arrival direction)•Omnidirectionality•Multi-frequency capability•Testing different metric theories of gravity
ILIAS meeting Mallorca 2005
V. Fafone
The experimental situation
1. MiniGRAIL
- Fast cooling of large masses (60 mK already achieved)
- Investigation of new material (CuAl 6%) - Q’s, effect of the suspension and trx fabrication
- Coupling of transducers with the sphere
ILIAS meeting Mallorca 2005
V. Fafone
2. TIGA experiments
•TIGA arrangements
•TIGA experiments
The experimental situation
ILIAS meeting Mallorca 2005
V. Fafone
To allow the detection and identification of GW signals it is useful to complement the IFO network with an advancedresonant-mass observatory
Added value• Duty cycle• Sky coverage• Instruments based on different principles
Strategy: Realization of a Resonant-mass GW ObservatoryComplementing the IFO Network
VIRGO - SFERA 2m first hybrid observatory
ILIAS meeting Mallorca 2005
V. Fafone
The short term proposed detector: SFERA
2 m dia, CuAlM = 33 tons
f1 = 1.0 kHz f2 = 1.9 kHz
The Collaboration
INFN (I)University of Geneva
(CH)University of Leiden (NL)
Cost ~ 3 MEURO
ILIAS meeting Mallorca 2005
V. Fafone
Mixing chamberSintered heat exchanger
50 mK plate
still
Joule-Thomson heat exchanger
3He pumping tube
50 mK radiation shield700 mK radiation shield
4 K radiation shield
Continuous heat exchanger
Pulse tubes
80 K radiation shield
C2 - G. Frossati,
Leiden
ILIAS meeting Mallorca 2005
V. Fafone
At the final sensitivity an underground location will be probably necessary, to avoid cosmic ray noise
M6 - G. Mazzitelli,
INFN - LNF
ILIAS meeting Mallorca 2005
V. Fafone
If funded in January 2006
Assembling and tests during 2006-2007 Commissioning at the beginning of 2008
Science Run at the beginning of 2009
SFERA
ILIAS meeting Mallorca 2005
V. Fafone
DUAL detector is based on new ideas1 – Wideband transducer: read displacement signal
between two massive resonator - M. Cerdonio et al. Phys. Rev. Lett. 87 031101 (2001)
2 - Selective readout: only GW sensitive normal modes must be measured - M. Bonaldi et al. Phys. Rev. D 68 102004 (2003)
Avoid resonant bandwidh limit and thermal noise contribution by the resonant transducer
Reduce overall thermal noise by rejecting the contribution of not useful modes
Dual R&D: a full open bandwidth acoustic detectorINFN and Dept of Physics: Firenze – Legnaro - Padova – Trento -
Urbino
ILIAS meeting Mallorca 2005
V. Fafone
Measurement of differential deformations of two nested resonators
Intermediate GW broadband
Dual: Main Concept
5.0 kHz
π Phase difference
The inner resonator is driven below frequency
The outer resonator is driven above resonance
ILIAS meeting Mallorca 2005
V. Fafone
Mode selection strategy
2-D Quadrupolar filter:X=X1 +X3 –X2 –X4
Capacitive transducer design
Large interrogation regions
Geometrically basedmode selection Reject high
frequency resonant modes which do not carry any GW signal
Bandwidth free from acoustic modes not sensitive to GW
Also FFP optical schemeF. Marin et.al, Phys. Lett. A 309, 15 (2003)
ILIAS meeting Mallorca 2005
V. Fafone
Mo Dual 16.4 ton height 3.0m 0.94m
SiC Dual 62.2 ton height 3.0m 2.9mQ/T=2x108 K-1
Evaluated sensitivity (SQL)
Antenna pattern: like 2 IFOs colocated and rotated by
45°
M. Bonaldi et al. Phys. Rev. D 68 102004 (2003)
ILIAS meeting Mallorca 2005
V. Fafone
a deep revision of the resonant detector design
DUAL is based on
AND
a challenging R&D on readout systems
TimelineR&D: 2005-2008Detailed design: 2008-2009
(Some topics are tackled within STREGA)
ILIAS meeting Mallorca 2005
V. Fafone
• Broadband amplification (5.0 kHz)
• Displacement gain factor about 10
• Negligible intrinsic thermal noise
• Compliance
Leverage type
amplifier
Selective readout system for DUAL: mechanical amplification stage
Capacitive readout
Electric Field
Optic readout
Fabry-Perotmirrors
T3 - P. Falferi,
IFN Trento
ILIAS meeting Mallorca 2005
V. Fafone
Progress towards a wide area optical readout
Usual cm-long cavities have small spot size (1mm) → higher order acoustic modes of the real system contribute to the noise
M1
M2
M3M4
D
Phys. Lett. A 309, 15 (2003)
To average out the noise, we need a spot size > 10 cm !!!!
Folded Fabry-Perot: FFP
relative shot noise limited displacement sensitivity: constantrelative freq. noise due to Brownian noise 1/ Nrelative freq. noise due to rad pressure noise 1/N2
effective increase of spot size
T3 - P. Falferi INFN Firenze
ILIAS meeting Mallorca 2005
V. Fafone
Apparatus for High voltage breakdown study
• Bias voltage in the 100 MV/m range
M2 - J.P. Zendri,
IFN Trento
Goal: 108 V/m
Achieved: 107 V/m
Measurement of V.B. of aluminum polished surfaces of cylindrical samples
Two axis
adjustment
- surface finishing effect- electrodes conditioning procedure- effect of dielectric films
Linear vertical stage
ILIAS meeting Mallorca 2005
V. Fafone
Test mass material characterization
Low temperature measurements of the Q factor of ceramic materials
M2 - J.P. Zendri,
INFN Legnaro
ILIAS meeting Mallorca 2005
V. Fafone