LIGO Status and Plans Barry Barish / Gary Sanders 13-May-02.

LIGOStatus and Plans

Barry Barish / Gary Sanders13-May-02

13-May-02 Baltimore / Koonin Briefing 2

LIGOoverall strategy

Strategy presented to NSB by Thorne / Barish in 1994

Search with a first generation interferometer where detection of gravitational waves are ‘plausible’» LIGO I uses demonstrated technologies

» Design sensitivity h ~ 10-21

» Plan is to interleave interferometer studies and improvements with incrementally improving data runs

» Search Goal: one year of integrated data at ~ design sensitivity

Advanced LIGO – detection “likely”» Do enabling R&D and design in parallel with LIGO I

» Incremental upgrades to laser, suspensions, optics, test masses

» Sensitivity: ~ 15x improvement (rate improves by 103 !!)

» Time scale: operational by 2008


Astrophysical Signaturesphysics goals

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”


Known Pulsars maximum gravitational wave signal

Jones, gr-qc/0111007


“Periodic Signals”pulsars sensitivity

Pulsars in our galaxy» non axisymmetric:

10-4 < < 10-6

» science: neutron star precession; interiors

» narrow band searches best

» all sky searches


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 short data taking runs)

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

2006 Begin Advanced LIGO installation


The LIGO Observatories

LIGO Hanford Observatory [LHO]

26 km north of Richland, WA

LIGO Livingston Observatory [LLO]

42 km east of Baton Rouge, LA


Summary integrated schedule


LIGOcosts & commitments


LIGOcontingency vs percent complete


Staffinghistory


Staffinglabor distribution projections


Major NSF Reviews Operations Renewal - 2001

Review of Operations Proposal Review of Advanced R&D Proposal

» Requested $175M for 5 years of operations

» Outstanding reviews – – “The Review Panel was extremely impressed with all aspects of

the LIGO Program and feels that it should receive the highest possible rating”

– “The Review Panel recommends that the NSF, even in the eventuality of overall fiscal pressures, support the LIGO program at the requested level.”

» Funding approved by NSB (Aug 01) at $160M

Annual LIGO Review» Concentrated on computing facilities

Next review – Fall 02


“The two goals of the program for the next five-year period were described to the Panel. The first goal is the operation of the LIGO I interferometers to search for gravitational waves with the strain sensitivity of h=10-21. This sensitivity is sufficient to make plausible, but not to guarantee, significant discoveries. The second goal is to pursue the R&D necessary for the design and construction of the Advanced LIGO interferometers with a 15-fold sensitivity improvement. Since the number of detectable sources is expected to scale as the cube of the sensitivity, Advanced LIGO is crucial in realizing the scientific goals of the program. The Review Panel felt that both of these goals are of paramount importance, and that the balance between the resources planned by LIGO on these two efforts is about right.”

NSF Review PanelLIGO Goals and Plans


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 short data taking runs)

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

2006 Begin LIGO II installation


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


LIGO laser

Nd:YAG

1.064 m

Output power > 8W in TEM00 mode


Prestabalized Laser performance

> 25,000 hours continuous operation

Frequency and lock very robust

TEM00 power > 8 watts

Non-TEM00 power < 10%

Improvements in optical path brought noise to better than design at low frequencies


Lock Acquisition


E7 Run SummaryLIGO + GEO Interferometers

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

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 %)

28 Dec 2001 - 14 Jan 2002 (402 hr)


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


Engineering Test Run2 weeks – Jan 02

PRELIMINARY

2 Km Hanford

4 Km Livingston

4 Km Hanford


Strain Spectra for E7comparison with design sensitivity

LIGO I Design


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


Stochastic Backgroundprojected sensitivities evolution


Improvements LHO 2K – Jan 02preliminary

• Closedfeedback loopfrom arms tolaser frequency

• Reallocationof gains withinlength controlservo system


Interferometer SensitivitiesEvolution of TAMA


Noise Levelcontributing components


Run Plancommissioning & data taking

• Science 1 run: 13 TB data “Upper Limits”» 29 June - 15 July

» 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


• Science 3 run: 142 TB data “Search Run”» 1 July 2003 -- 1January 2004

» 26 weeks -- 50% of 1 yr



LIGO Scientific CollaborationLIGO I

US Universities: Caltech LIGO/CaRT/CEGG/CACR Carleton Cornell Cal State University Dominguez Hills Florida• Louisiana State Louisiana Tech Michigan MIT LIGO Oregon Penn State Southern Syracuse Texas-Brownsville Wisconsin-Milwaukee

International Members: ACIGA (Australia) GEO 600 (UK/Germany) IUCAA (Pune, India)

US Agencies & Institutions FNAL (DOE) Goddard-GGWAG (NASA) Harvard-Smithsonian

International partners (have MOUs with LIGO Laboratory):

TAMA (Japan) Virgo (France/Italy)

21 Institutions, 26 Groups, 281 Members


LIGOsummary

LIGO construction completed in 2000

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 ~ 2008

LIGO Status and Plans Barry Barish / Gary Sanders 13-May-02.

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