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
13-May-02 Baltimore / Koonin Briefing 3
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”
13-May-02 Baltimore / Koonin Briefing 4
Known Pulsars maximum gravitational wave signal
Jones, gr-qc/0111007
13-May-02 Baltimore / Koonin Briefing 5
“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
13-May-02 Baltimore / Koonin Briefing 6
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
13-May-02 Baltimore / Koonin Briefing 7
The LIGO Observatories
LIGO Hanford Observatory [LHO]26 km north of Richland, WA
LIGO Livingston Observatory [LLO]
42 km east of Baton Rouge, LA
13-May-02 Baltimore / Koonin Briefing 8
Summary integrated schedule
13-May-02 Baltimore / Koonin Briefing 9
LIGOcosts & commitments
13-May-02 Baltimore / Koonin Briefing 10
LIGOcontingency vs percent complete
13-May-02 Baltimore / Koonin Briefing 11
Staffinghistory
13-May-02 Baltimore / Koonin Briefing 12
Staffinglabor distribution projections
13-May-02 Baltimore / Koonin Briefing 13
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
13-May-02 Baltimore / Koonin Briefing 14
“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
13-May-02 Baltimore / Koonin Briefing 15
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
13-May-02 Baltimore / Koonin Briefing 16
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
13-May-02 Baltimore / Koonin Briefing 17
LIGO laser
Nd:YAG
1.064 m
Output power > 8W in TEM00 mode
13-May-02 Baltimore / Koonin Briefing 18
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
13-May-02 Baltimore / Koonin Briefing 19
Lock Acquisition
13-May-02 Baltimore / Koonin Briefing 20
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+ H2locked 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)
13-May-02 Baltimore / Koonin Briefing 21
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
13-May-02 Baltimore / Koonin Briefing 22
Engineering Test Run2 weeks – Jan 02
PRELIMINARY
2 Km Hanford
4 Km Livingston
4 Km Hanford
13-May-02 Baltimore / Koonin Briefing 23
Strain Spectra for E7comparison with design sensitivity
LIGO I Design
13-May-02 Baltimore / Koonin Briefing 24
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
13-May-02 Baltimore / Koonin Briefing 25
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),
=========================================================================
13-May-02 Baltimore / Koonin Briefing 26
Detecting the Earth Tides Sun and Moon
13-May-02 Baltimore / Koonin Briefing 27
Stochastic Backgroundprojected sensitivities evolution
13-May-02 Baltimore / Koonin Briefing 28
Improvements LHO 2K – Jan 02preliminary
• Closedfeedback loopfrom arms tolaser frequency
• Reallocationof gains withinlength controlservo system
13-May-02 Baltimore / Koonin Briefing 29
Interferometer SensitivitiesEvolution of TAMA
13-May-02 Baltimore / Koonin Briefing 30
Noise Levelcontributing components
13-May-02 Baltimore / Koonin Briefing 31
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» 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
13-May-02 Baltimore / Koonin Briefing 32
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
13-May-02 Baltimore / Koonin Briefing 33
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
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