viviana fafone infn - lnf

ILIAS meeting Mallorca 2005

V. Fafone

Viviana FafoneINFN - LNF

Future plans forresonant detectors

www.lnf.infn.it/esperimenti/rog


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CERN RE 5

LNF INFN

MiniGrail

Leiden

LNL INFN


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• 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:


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1998

200110-20

EXPLORER

880 950

WIDENING THE BAND…

NAUTILUS

2001

AURIGA

19992003

10-20

2003


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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


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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


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Very good agreement with noise predictions

all these noise sources will scale with temperature

one-sided Shh

Present Status of AURIGAPresent Status of AURIGA


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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)


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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


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TOWARDS MORE POWERFUL AND SENSITIVE ACOUSTIC DETECTORS


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“…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


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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. …”


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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


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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


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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


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2. TIGA experiments

•TIGA arrangements

•TIGA experiments

The experimental situation


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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


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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


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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


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At the final sensitivity an underground location will be probably necessary, to avoid cosmic ray noise

M6 - G. Mazzitelli,

INFN - LNF


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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


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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


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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


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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)


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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)


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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)


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• 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


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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


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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


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Test mass material characterization

Low temperature measurements of the Q factor of ceramic materials

M2 - J.P. Zendri,

INFN Legnaro


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