overview ground-based interferometers - ligobcbact/talks05/amaldi-6 overview... · 20-june-05...

Overview Ground-based Interferometers

Barry BarishCaltechAmaldi-6

20-June-05

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InterferometerDetectors

LIGO Louisiana 4000mTAMA Japan

300m

Virgo Italy 3000m

GEO Germany 600mAIGO Australia

future

LIGO Washington 2000m & 4000m

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Network of Interferometers

LIGO

detection confidence

GEO VirgoTAMA

AIGOlocate the sources

decompose the polarization of gravitational waves

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Interferometer Concept

As a wave passes, the arm lengths change in different ways….

…causing the interference pattern

to change at the photodiode

SuspendedMasses

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Limiting Noise Sources

• Seismic noise & vibration limit at low frequencies

• Atomic vibrations (Thermal Noise) inside components limit at mid frequencies

• Quantum nature of light (Shot Noise) limits at high frequencies

• Myriad details of the lasers, electronics, etc., can make problems above these levels

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TAMA 300

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Automated Data Taking in DT9 -

Master-system (intelligent switching)PC + PCI boards + LabVIEW64ch digital I/O 16ch A/D + 24ch D/A

Lock acquisitionAuto adjustmentInterface with external system

Self-switching sub-systemLogic circuit + Embedded micro processor

Laser source controlMC controlLaser intensity stabilizationBeam axes control

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Sensitivity in DT9

Recycling gain: 4.5Extended control band width for the laser frequencyImproved strain sensitivity: h=1.7x10-21 /Hz1/2 @1kHz

20-June-05 Amaldi-6 - Interferometer Overview - Barish 9Observable distance for NS inspiral binaries

TAMA

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TAMA Ringdown Analysis

GEO600

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GEO 600 – Optical Layout

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GEO Sensitivity Evolution

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LIGO

LIGO HanfordLIGO Livingston

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Evolution of LIGO Sensitivity

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Active Seismic Isolation at LLO

Hydraulic external pre-isolator (HEPI)Signals from sensors on ground and cross-beam are blended and fed into hydraulic actuatorsStatus:» Installed on all 4 piers at

each of nine vacuum chambers

» System is operational

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Active Seismic Isolation at LLO

Can lock (and do commissioning work!) during daytimeAble to stay locked even when train passes nearby

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LIGO Livingston Sensitivity

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LIGO S4 – Best Performance

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Detection of Periodic Sources

Pulsars in our galaxy: “periodic”» search for observed neutron stars » all sky search (computing challenge)» r-modes

Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes.

Amplitude modulation due to the detector’s antenna pattern.

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LIGO – GEO Directed Pulsar Search

28 Radio Sources

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GEO-LIGO - Resultsh0 95% UL Pulsars

10-24 < h0 < 5 10-24 20

5 10-24 < h0 < 10-23 4

h0 > 10-23 4

ellipticity ε Pulsars

10-6 < ε < 10-5 4

10-5 < ε < 10-4 16

ε > 10-4 8

• Lowest 95% UL on h0 = 1.7 10-24 (J1910-5959D)

• Lowest bound on e = 4.5 10-6 (J2124-3358)

• Crab pulsar:

• h0 = 4.1 10-23

• ε = 2.1 10-2 (~30 times spin-down upper limit)

Crab pulsar

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Detection of Periodic Sources

Pulsars in our galaxy

Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes.

Amplitude modulation due to the detector’s antenna pattern.

NEW RESULT28 known pulsars

NO gravitational waves

ε < 10-5 – 10-6

(no mountains > 10 cm

ALL SKY SEARCHenormous computing challenge

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Einstein@Home

LIGO Pulsar Search using home pc’s

BRUCE ALLENProject Leader

Univ of Wisconsin Milwaukee

LIGO, UWM, AEI, APS

http://einstein.phys.uwm.edu

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Virgo

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Virgo Seismic Performance

Thermal noise

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Virgo - Sensitivity Goal

Designed to have good sensitivity at low frequencies

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Virgo Commissioning

Extragalactic sensitivity Extragalactic sensitivity toto NS/NS NS/NS coalescences coalescences

55 55 kpc kpc

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Advanced LIGO

Active Seismic

Multiple Suspensions

Improved Optics

Higher Power Laser

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Advanced LIGOEnhanced Systems

• laser• suspension• seismic isolation• test mass

RateImprovement

~ 104

+narrow band

optical configuration

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From Amaldi-6 Onwards

From Present Generation Advanced Detectors Next Generation Detectors (QND)

From 8 Mpc (NN inspiral) 200 Mpc and beyond

From Upper Limits Searches Detections

From Generic Waveforms Specified Waveforms

From Single Detectors Global Networks