LIGO-G020262-00-M LIGO Status and Plans Barry Barish AIP Conference, Sydney Australia 11-July-02.

LIGO-G020262-00-M

LIGO Status and Plans

Barry BarishAIP Conference, Sydney Australia

11-July-02

11-July-02 AIP Conference 2LIGO-G020262-00-M

6LIGO-G010036-00-M

LIGO Plansschedule

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

2007

LIGO-G020262-00-M

A tour of LIGO


LIGO Sites

Hanford Observatory

LivingstonObservatory


LIGO Livingston Observatory


LIGO Hanford Observatory


Detection Strategycoincidences

Two Sites - Three Interferometers» Single Interferometer non-gaussian level ~50/hr

» Hanford (Doubles) correlated rate (x1000) ~1/day

» Hanford + Livingston uncorrelated (x5000) <0.1/yr

Data Recording (time series)» gravitational wave signal (0.2 MB/sec)

» total data (16 MB/s)

» on-line filters, diagnostics, data compression

» off line data analysis, archive etc

Signal Extraction» signal from noise (vetoes, noise analysis)

» templates, wavelets, etc

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The Beam Tube&

Enclosure


LIGO Facilitiesbeam tube enclosure

• minimal enclosure

• reinforced concrete

• no services


LIGObeam tube

LIGO beam tube under construction in January 1998

65 ft spiral welded sections

girth welded in portable clean room in the field

1.2 m diameter - 3mm stainless50 km of weld

NO LEAKS !!


LIGO I the noise floor

Interferometry is limited by three fundamental noise sources

seismic noise at the lowest frequencies thermal noise at intermediate frequencies shot noise at high frequencies

Many other noise sources lurk underneath and must be controlled as the instrument is improved


Beam Tube bakeout

• I = 2000 amps for ~ 1 month

• no leaks !!

• final vacuum at level where it is not source of limiting noise (even future detectors)

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Vacuum Chambers


LIGOvacuum chambers


Vacuum Chambersvibration isolation systems

» Reduce in-band seismic motion by 4 - 6 orders of magnitude» Compensate for microseism at 0.15 Hz by a factor of ten» Compensate (partially) for Earth tides

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Seismic Isolation


Seismic Isolation springs and masses

damped springcross section


Seismic Isolationconstrained layer damped springs


Seismic Isolation

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Optics&

Suspensions


Core Opticsfused silica

LIGO requirements Surface uniformity < 1 nm rms Scatter < 50 ppm Absorption < 2 ppm ROC matched < 3% Internal mode Q’s > 2 x 106

LIGO measurements• central 80 mm of 4ITM06 (Hanford 4K) • rms = 0.16 nm• optic far exceeds specification.

Surface figure = / 6000


Seismic Isolationsuspension system

• support structure is welded tubular stainless steel • suspension wire is 0.31 mm diameter steel music wire

• fundamental violin mode frequency of 340 Hz

suspension assembly for a core optic


Core Optics installation and alignment

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Laser&

Mode Cleaner


LIGO laser

Nd:YAG

1.064 mm

Output power > 8W in TEM00 mode


Laserstabilization

IO

10-WattLaser

PSL Interferometer

15m4 km

Tidal Wideband

Deliver pre-stabilized laser light to the 15-m mode cleaner• Frequency fluctuations• In-band power fluctuations• Power fluctuations at 25 MHz

Provide actuator inputs for further stabilization• Wideband

• Tidal

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


Prestabilized Laser frequency noise

Simplification of beam path external to vacuum system eliminates peaks due to vibrations

Broadband noise better than spec in 40-200 Hz region


Pre-stabilized Laserlaboratory data vs e2e simulation

LIGO-G020262-00-M

Locking the

Interferometers


Interferometerlocking

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”


Lock Acquisition


LIGOwatching the interferometer lock

signal

LaserX Arm

Y Arm

Composite Video


LIGOwatching the interferometer lock

signal

X Arm

Y Arm

Laser

X arm

Anti-symmetricport

Y arm

Reflected light

2 min

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E7 Engineering Run


LIGO Interferometers E7 sensitivities


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

E7 Run SummaryLIGO + GEO Interferometers

Coincidence Data

All segments Segments >15min2X: 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)


An earthquake occurred, starting at UTC 17:38.

The plot shows the band limited rms output in counts over the 0.1- 0.3Hz band for four seismometer channels. We turned off lock acquisition and are waiting for the ground motion to calm down.

From electronic logbook 2-Jan-02

Engineering Rundetecting earthquakes


17:03:03

01/02/2002

=========================================================================

Seismo-Watch

Earthquake Alert Bulletin No. 02-64441

=========================================================================

Preliminary data indicates a significant earthquake has occurred:

Regional Location: VANUATU ISLANDS

Magnitude: 7.3M

Greenwich Mean Date: 2002/01/02

Greenwich Mean Time: 17:22:50

Latitude: 17.78S

Longitude: 167.83E

Focal depth: 33.0km

Analysis Quality: A

Source: National Earthquake Information Center (USGS-NEIC)

Seismo-Watch, Your Source for Earthquake News and Information.

Visit http://www.seismo-watch.com

=========================================================================

All data are preliminary and subject to change.

Analysis Quality: A (good), B (fair), C (poor), D (bad)

Magnitude: Ml (local or Richter magnitude), Lg (mblg), Md (duration),

=========================================================================


Detecting the Earth Tides Sun and Moon


Run Plancommissioning & data taking

Science 1 run: 13 TB data “Upper Limits”» 29 June - 15 July (delayed until >Aug 1 because of

broken suspension wire)» 2.5 weeks - comparable to E7» Target sensitivity: 200x design

Science 2 run: 44 TB data “Upper Limits”» 22 November - 6 January 2003» 8 weeks -- 15% of 1 yr» Target sensitivity: 20x design

Science 3 run: 142 TB data “Search Run”» 1 July 2003 -- 1January 2004» 26 weeks -- 50% of 1 yr» Target sensitivity: 5x design


Commissioning Status for

S1 Science Run


Locked in power recycled configuration» recycling factor up to 25, but typically ~15

Common mode servo implemented» Frequency stabilization from average arm length» Establishes control system “gain hierarchy”

5 W power into mode cleaner » Attenuators at photodiodes give effective input power 20 - 40 mW

Tidal feedback operational » Lock duration up to 15 hours

DISPLACEMENT Sensitivity

LHO 2 km InterferometerStatus

Summer 2001 ~ 3 x 10-16 m/Hz1/2

December 2001 (E7) ~ 5 x 10-17 m /Hz1/2 (~600 Hz)

Spring 2002 ~ 2 x 10-17 m /Hz1/2 (~350 Hz)


Interferometersensitivity history


LHO 4 km Interferometerstatus

In-vacuum installation completed last summer Digital suspension controllers

» Greater flexibility for tuning servos to improve reliability/noise» Permits frequency dependent orthogonalization of the

displacement and angular control of the suspensions» Will be implemented on other interferometers after tests done

1 W power into mode cleaner » Attenuators at photodiodes give effective input power 20 mW

Locked in power recycled configuration » Recycling factor typically 40-50

Tidal feedback operational » Locks up to 4 hours

DISPLACEMENT Sensitivity ~2 x 10-16 m/Hz1/2


LLO 4 km Interferometer status

Power recycled configuration 1.9 W power input laser power into mode cleaner

» Power recycling gain ~ 50

» 25-30 dB attenuation at dark port

Reasonably robust lock during night» Up to 4 hours

» 15 s – 3 min lock acquisition time

» Tidal feedback operational

» Wavefront alignment control operating on end mirrors

» Microseismic feedforward reduces the dynamic range required from the controller (unique to LLO at present time)

» PEPI reduces the seismic noise injected between 0.3 to 5 Hz at the end masses

DISPLACEMENT Sensitivity ~1.5 x 10-17 m/Hz1/2 @ 400 - 600 Hz


Astrophysical Sourcessignatures and data analysis

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”


“Chirp Signal”binary inspiral

•distance from the earth r•masses of the two bodies•orbital eccentricity e and orbital inclination i

determine


Interferometer Data40 m prototype

Real interferometer data is UGLY!!!(Gliches - known and unknown)

LOCKING

RINGING

NORMAL

ROCKING


The Problem

How much does real data degrade complicate the data analysis and degrade the sensitivity ??

Test with real data by setting an upper limit on galactic neutron star inspiral rate using 40 m data


“Clean up” data stream

Effect of removing sinusoidal artifacts using multi-taper methods

Non stationary noise Non gaussian tails


Inspiral ‘Chirp’ Signal

Template Waveforms

“matched filtering”687 filters

44.8 hrs of data39.9 hrs arms locked25.0 hrs good data

sensitivity to our galaxyh ~ 3.5 10-19 mHz-1/2

expected rate ~10-6/yr


Optimal Signal Detection

Want to “lock-on” to one of a set of known signals

Requires:• source modeling• efficient algorithm• many computers


Detection Efficiency

• Simulated inspiral events provide end to end test of analysis and simulation code for reconstruction efficiency

• Errors in distance measurements from presence of noise are consistent with SNR fluctuations


Results from 40m Prototype

Loudest event usedto set upper-limit onrate in our Galaxy:

R90% < 0.5 / hour


Setting a limit

Upper limit on event rate can be determined from SNR of ‘loudest’ event

Limit on rate:R < 0.5/hour with 90% CL = 0.33 = detection efficiency

An ideal detector would set a limit:R < 0.16/hour


gravitational waves

’s

light

“Burst Signal”supernova


Supernovaegravitational waves

Non axisymmetric collapse ‘burst’ signal

Rate1/50 yr - our galaxy3/yr - Virgo cluster


pulsar proper motions

Velocities - young SNR(pulsars?) > 500 km/sec

Burrows et al

recoil velocity of matter and neutrinos

Supernovaeasymmetric collapse?


Supernovaesignatures and sensitivity


Periodic Signalsspinning neutron stars

Isolated neutron stars with deformed crust

Newborn neutron stars with r-modes

X-ray binaries may be limited by gravitational waves


“Periodic Signals”pulsars sensitivity

Pulsars in our galaxy»non axisymmetric:

10-4 < < 10-6

»science: neutron star precession; interiors

»narrow band searches best


“Stochastic Background”cosmological signals

‘Murmurs’ from the Big Bangsignals from the early universe

Cosmic microwave background


Stochastic Backgroundsensitivity

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


Stochastic Backgroundcoherence plots LHO 2K & LHO 4K


Stochastic Backgroundcoherence plot LHO 2K & LLO 4K


Stochastic Backgroundanalysis in progress

Analytic calculation of expected upper limits (~50 hrs): ~2 x 105 for LLO-LHO 2k, ~ 6 x 104 for LHO 2k-LHO 4k

Coherence measurements of GW channels show little coherence for LLO-LHO 2k correlations

Power line monitor coherence investigations suggest coherence should average out over course of the run

Plan to investigate effect of line removal on LHO 2k-LHO 4k correlations (e.g., reduction in correlated noise, etc.)

Plan to inject simulated stochastic signals into the data and extract from the noise

Plan to also correlate LLO with ALLEGRO bar detector» ALLEGRO was rotated into 3 different positions during E7


Stochastic Backgroundprojected sensitivities


LIGOconclusions

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

Significant improvements in sensitivity anticipated to begin

about 2006

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Finis


Planned Detector Modificationsactive external seismic

HAM

BSC

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Advanced Detector R&D and Advanced LIGO


Advanced LIGO R&D Status

Working toward construction proposal to Fall 2002 “bottoms-up” costing has nearly been completed Plan assumes construction funding available 1Q2005

» some long lead funds in 1Q2004 Supports an installation start of 4Q2006 Soon ready to confront scope decisions (number of

interferometers, trimming features to control costs, etc.)

Advanced R&D program is proceeding well GEO and ACIGA teams forming strong international

partnership


Advanced LIGO R&D Status Interferometer Sensing & Control (ISC):

» GEO 10m “proof of concept” experiment:– Preparation proceeding well– Results available for 40m Program in early 2003 (lock acquisition

experience, sensing matrix selection, etc.)

» 40m Lab for Precision Controls Testing:– Infrastructure has been completed (i.e. PSL, vacuum controls & envelope,

Data Acquisition system, etc.)– Working on the installation of the 12m input MC optics and suspensions,

and suspension controllers by 3Q02

» Gingin facility for High Power Testing:– Within the next year the LIGO Lab will deliver two characterized sapphire

test masses and a prototype thermal compensation system (beam scan and/or ring heater)

– The facility development is advancing nicely– Activities closely linked with subsystem, LASTI R&D plan


Advanced LIGO R&D Status Seismic Isolation system (SEI):

» Development of pre-isolation system accelerated for use in retrofit on initial LIGO– hydraulic & electro-magnet actuation variants– To be tested at the LASTI facility

» “Technology Demonstrator” system has been fabricated– a two stage, 12 degree of freedom active, stiff, isolation system– being installed into the Stanford Engineering Test Facility (ETF)

LASTI infrastructure has been completed (including BSC stack to support pre-isolation full scale testing for initial LIGO)


Advanced LIGO R&D Status

Suspension System (SUS):» Complete fused-quartz fiber suspensions

functioning in the GEO-600 interferometer

» Progress, in theory and in experiment, on both circular fibers (tapered) and ribbons

» Dynamics testing is underway on a quadruple pendulum prototype

» Silica-sapphire hydroxy-catalysis bonding looks feasible; silica-leadglass to be explored

» Significant design work underway for ‘triple’ suspensions

» TNI nearing final results for fused silica; sapphire mirrors ready in Fall 2002 for next phase


Advanced LIGO R&D Status Core Optics Components (COC):

» New optical homogeneity measurements along the ‘a’ crystal axis are close to acceptable (13nm RMS over 80mm path length)

» Tests to compensate for optical inhomogeneity if required, look promising (computer controlled ‘spot’ polishing and ion beam etching)

» Recent sapphire annealing efforts are encouraging (reductions to 20 ppm/cm vs a requirement of 10 ppm/cm)

» Coatings on large optics show sub-ppm losses (SMA/Mackowski)

» Coating mechanical loss program in full swing; materials rather than interfaces seem to be the culprit

LIGO-G020262-00-M LIGO Status and Plans Barry Barish AIP Conference, Sydney Australia 11-July-02.

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Transcript of LIGO-G020262-00-M LIGO Status and Plans Barry Barish AIP Conference, Sydney Australia 11-July-02.