LIGO Present and Future

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LIGO Present and Future

• Barry Barish
• Directory of the LIGO Laboratory

2
LIGO I Schedule and Plan
LIGO I has been built by LIGO Lab (Caltech MIT)

• 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

3
LIGO Scientific Collaboration
March 02
LSC Institutional Membership 35 institutions gt
350 collaborators

• University of Adelaide ACIGA
• Australian National University ACIGA
• California State Dominquez Hills
• Caltech LIGO
• Caltech Experimental Gravitation CEGG
• Caltech Theory CART
• University of Cardiff GEO
• Carleton College
• Cornell University
• University of Florida _at_ Gainesville
• Glasgow University GEO
• University of Hannover GEO
• Harvard-Smithsonian
• India-IUCAA
• IAP Nizhny Novgorod
• Iowa State University
• Joint Institute of Laboratory Astrophysics

• LIGO Livingston LIGOLA
• LIGO Hanford LIGOWA
• Louisiana State University
• Louisiana Tech University
• MIT LIGO
• Max Planck (Garching) GEO
• Max Planck (Potsdam) GEO
• University of Michigan
• Moscow State University
• NAOJ - TAMA
• University of Oregon
• Pennsylvania State University Exp
• Pennsylvania State University Theory
• Southern University
• Stanford University
• University of Texas_at_Brownsville
• University of Western Australia ACIGA
• University of Wisconsin_at_Milwaukee

International India, Russia, Germany, U.K,
Japan and Australia.
The international partners are involved in all
aspects of the LIGO research program.
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LIGO Sites
Hanford Observatory
Livingston Observatory
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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) lt0.1
  /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
2000 amps for one month
Fermilab Magnet Power Supply
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Vacuum Chambers and Seismic Isolation
constrained layer damped springs
Vacuum Chambers
Gate Valve
Vacuum Chamber
passive isolation
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LIGO I Suspension and Optics
fused silica
Single suspension 0.31mm music wire
Surface figure ?/ 6000

• surface uniformity lt 1nm rms
• scatter lt 50 ppm
• absorption lt 2 ppm
• internal Qs gt 2 106

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Commissioning the LIGO I Subsystems
stablization
10-4 Hz/Hz1/2
10-7 Hz/Hz1/2
10-1 Hz/Hz1/2
LIGO I Goal
NdYag 1.064 mm Output power gt8 Watt TEM00 mode
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LIGO Prestablized Laser Data vs Simulation
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LIGO I Interferometer Configuration
end test mass
Requires test masses to be held in position to
10-10-10-13 meter Locking the interferometer
Light bounces back and forth along arms about 150
times
Light is recycled about 50 times
input test mass
Laser
signal
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Locking the LIGO I Interferometers
One meter, about 40 inches
Human hair, about 100 microns
Earthtides, about 100 microns
Wavelength of light, about 1 micron
Microseismic motion, about 1 micron
Atomic diameter, 10-10 meter
Precision required to lock, about 10-10 meter
LIGO sensitivity, 10-18 meter
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Watching LIGO Lock
Y Arm
Laser
X Arm
signal
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Watching an Early Lock
X arm
Y arm
Y Arm
Anti-symmetricport
Reflected light
Laser
X Arm
signal
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Lock Acquisition
LIGO I Dynamical Control Model by Matt
Evans Caltech
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LIGO Engineering Run (E7) Sensitivities
Final LIGO Milestone ----------- Coincidences Bet
ween the Sites in 2001 Engineering Run 28 Dec
01 to 14 Jan 02
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LIGO GEO Interferometers
28 Dec 2001 - 14 Jan 2002 (402 hr)
Coincidence Data All
segments Segments gt15min 2X H2, L1 locked
160hrs (39) 99hrs
(24) clean 113hrs (26)
70hrs (16) H2,L1 longest clean segment 150 3X
L1H1 H2 locked 140hrs (35)
72hrs (18) clean 93hrs (21)
46hrs (11) L1H1 H2 longest clean
segment 118 4X L1H1 H2 GEO 77 hrs
(23 ) 26.1 hrs (7.81 ) 5X ALLEGRO

• Singles data
• All segments Segments gt15min
• L1 locked 284hrs (71) 249hrs
  (62)
• L1 clean 265hrs (61) 231hrs
  (53)
• L1 longest clean segment 358
• H1 locked 294hrs (72) 231hrs
  (57)
• H1 clean 267hrs (62) 206hrs
  (48)
• H1 longest clean segment 404
• H2 locked 214hrs (53) 157hrs
  (39)
• H2 clean 162hrs (38) 125hrs
  (28)
• H2 longest clean segment 724

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 RD 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