LIGO Present and Future

Barry BarishDirectory of the LIGO Laboratory

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LIGO I Schedule and Plan

1996 Construction Underway (mostly civil)

1997 Facility Construction (vacuum system) 1998 Interferometer Construction (complete facilities)

1999 Construction Complete (interferometers in vacuum) 2000 Detector Installation (commissioning subsystems)

2001 Commission Interferometers (first coincidences)

2002 Sensitivity studies (initiate LIGO I Science Run)

2003+ LIGO I data run (one year integrated data at h ~ 10-21)

2006+ Begin ‘Advanced LIGO’ installation

LIGO I has been built by LIGO Lab (Caltech & MIT)

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LIGO Scientific Collaboration

University of Adelaide ACIGAAustralian National University ACIGACalifornia State Dominquez HillsCaltech LIGOCaltech Experimental Gravitation CEGGCaltech Theory CARTUniversity of Cardiff GEOCarleton CollegeCornell UniversityUniversity of Florida @ GainesvilleGlasgow University GEOUniversity of Hannover GEOHarvard-SmithsonianIndia-IUCAAIAP Nizhny NovgorodIowa State UniversityJoint Institute of Laboratory

Astrophysics

LIGO Livingston LIGOLALIGO Hanford LIGOWALouisiana State UniversityLouisiana Tech UniversityMIT LIGOMax Planck (Garching) GEOMax Planck (Potsdam) GEOUniversity of MichiganMoscow State UniversityNAOJ - TAMAUniversity of OregonPennsylvania State University ExpPennsylvania State University TheorySouthern UniversityStanford UniversityUniversity of Texas@BrownsvilleUniversity of Western Australia ACIGAUniversity of Wisconsin@Milwaukee

LSC Institutional Membership35 institutions > 350 collaborators

International India, Russia,

Germany, U.K, Japan

and Australia.

The international partners are

involved in all aspects of the LIGO research program.

March 02

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LIGO Sites

HanfordObservatory

LivingstonObservatory

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LIGO Livingston Observatory

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LIGO Hanford Observatory

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Coincidences between the LIGO Sites

Two Sites – Three interferometers Single interferometer non-gaussian level ~50/hour Local coincidence - Hanford 2K and 4K (÷~1000) ~1/day Hanford/Livingston coincidence (uncorrelated) <0.1/yr GEO coincidence further reduces the false signal rate

Data (continuous time-frequency record) Gravitational wave signal 0.2MB/sec Total data recorded 16 MB/sec

Gravitational Wave Signal Extraction Signal from noise (noise analysis, vetoes, coincidences, etc

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LIGO Facility Noise Levels

Fundamental Noise Sources Seismic at low frequencies Thermal at mid

frequencies Shot at high frequencies

Facility Noise Sources (example)

Residual Gas 10-6 torr H2 unbaked 10-9 torr H2 baked

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Beam Pipe and Enclosure

Minimal Enclosure (no services) Beam Pipe

1.2m diam; 3 mm stainless 65 ft spiral weld sections 50 km of weld (NO LEAKS!)

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Baking out the LIGO Beam Pipe

insulation

Fermilab Magnet Power Supply

~ 2000 amps for one month

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Vacuum Chambers and Seismic Isolation

Gate Valve

constrained layer damped springsVacuum Chambers

Vacuum Chamberpassive isolation

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LIGO I Suspension and Optics

Single suspension 0.31mm music wire

fused silica

Surface figure = / 6000

• surface uniformity < 1nm rms• scatter < 50 ppm• absorption < 2 ppm• internal Q’s > 2 106

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Commissioning the LIGO I Subsystems

Nd:Yag 1.064 mm Output power>8 Watt TEM00 mode

IO

10-WattLaser

PSL Interferometer

15m

4 km

Tidal Wideband

stablization

10-1 Hz/Hz1/2 10-4 Hz/Hz1/2 10-7 Hz/Hz1/2

LIGO IGoal

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LIGO Prestablized Laser Data vs Simulation

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LIGO I Interferometer Configuration

Laser

end test mass

Light bounces back and forth along arms about 150 times

input test massLight is “recycled” about 50 times

signal

Requires test masses to be held in position to 10-10-10-13 meter:“Locking the interferometer”

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Locking the LIGO I Interferometers

One meter, about 40 inches

Human hair, about 100 microns000,10

Wavelength of light, about 1 micron100

LIGO sensitivity, 10-18 meter000,1

Nuclear diameter, 10-15 meter000,100

Atomic diameter, 10-10 meter000,10

Earthtides, about 100 microns

Microseismic motion, about 1 micron

Precision required to lock, about 10-10 meter

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Watching LIGO Lock

signal

LaserX Arm

Y Arm

Composite Video

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Watching an ‘Early’ Lock

signalX Arm

Y Arm

Laser

X arm

Anti-symmetricport

Y arm

Reflected light

2 min

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Lock Acquisition

LIGO IDynamical

Control Model

byMatt Evans

Caltech

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LIGO Engineering Run (E7) Sensitivities

Final LIGOMilestone-----------

“CoincidencesBetween the Sites in 2001”

EngineeringRun

28 Dec 01 to

14 Jan 02

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Singles data All segments Segments >15min

L1 locked 284hrs (71%) 249hrs (62%)L1 clean 265hrs (61%) 231hrs (53%)L1 longest clean segment: 3:58

H1 locked 294hrs (72%) 231hrs (57%)H1 clean 267hrs (62%) 206hrs (48%) H1 longest clean segment: 4:04

H2 locked 214hrs (53%) 157hrs (39%)H2 clean 162hrs (38%) 125hrs (28%)H2 longest clean segment: 7:24

LIGO + GEO Interferometers

Coincidence Data

All segments Segments >15min

2X: H2, L1locked 160hrs (39%) 99hrs (24%)clean 113hrs (26%) 70hrs (16%)H2,L1 longest clean segment: 1:50

3X : L1+H1+ H2

locked 140hrs (35%) 72hrs (18%)

clean 93hrs (21%) 46hrs (11%)

L1+H1+ H2 : longest clean segment: 1:18

4X: L1+H1+ H2 +GEO:

77 hrs (23 %) 26.1 hrs (7.81 %)

5X: ALLEGRO + …

28 Dec 2001 - 14 Jan 2002 (402 hr)

Conclusion: Large Duty Cycle Looks Attainable

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LIGO Sensitivity History

Hanford 2K 06-02 Livingston 4K 06-02

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LIGO I Astrophysical Sources Search Efforts

Compact binary inspiral: “chirps” NS-NS waveforms are well described BH-BH need better waveforms search technique: matched templates

Supernovae / GRBs: “bursts” burst signals in coincidence with signals in

electromagnetic radiation prompt alarm (~ one hour) with neutrino

detectors Pulsars in our galaxy: “periodic”

search for observed neutron stars (frequency, doppler shift)

all sky search (computing challenge) r-modes

Cosmological Signals “stochastic background”

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Stochastic Background Sensitivity

Detection Cross correlate Hanford and Livingston Interferometers

Good Sensitivity GW wavelength 2x detector baseline f 40 Hz

Initial LIGO Sensitivity 10-5

Advanced LIGO Sensitivity 5 10-9

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Stochastic Background Coherence Plots

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Stochastic Background Sensitivities

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LIGO I Status and Plans

LIGO construction complete

LIGO commissioning and testing ‘on track’

Engineering test runs underway, during period when emphasis is on commissioning, detector sensitivity and reliability. (Short upper limit data runs interleaved)

First Science Search Run : first search run will begin during 2003; goal is to obtain and analyze one year of integrated data at h ~ 10-

21 by 2006

Significant improvements in sensitivity anticipated to begin about 2006

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Advanced LIGO Status and Plans

GEO, ACIGA and LIGO form a very strong international partnership to develop and manage Advanced LIGO

Working toward NSF construction proposal to be submitted in Fall 2002

Advanced R&D program is proceeding well Baseline design and installation scenarios established (alternative

carried) “Bottoms-up” costing has nearly been completed Plan assumes long lead funds available in 2004; major

construction funds in 2005

Supports an installation by 2007