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LIGO Status and Plans

LIGO Status and Plans. Barry Barish AIP Conference, Sydney Australia 11-July-02. 2007. A tour of LIGO. LIGO Sites. Hanford Observatory. Livingston Observatory. LIGO Livingston Observatory. LIGO Hanford Observatory. Detection Strategy coincidences.

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LIGO Status and Plans

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

  2. 2007 AIP Conference

  3. A tour of LIGO

  4. LIGO Sites Hanford Observatory Livingston Observatory AIP Conference

  5. LIGO Livingston Observatory AIP Conference

  6. LIGO Hanford Observatory AIP Conference

  7. 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 AIP Conference

  8. The Beam Tube&Enclosure

  9. LIGO Facilitiesbeam tube enclosure • minimal enclosure • reinforced concrete • no services AIP Conference

  10. 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 stainless 50 km of weld NO LEAKS !! AIP Conference

  11. 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 AIP Conference

  12. 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) AIP Conference

  13. Vacuum Chambers

  14. LIGOvacuum chambers AIP Conference

  15. 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 AIP Conference

  16. Seismic Isolation

  17. Seismic Isolationsprings and masses damped springcross section AIP Conference

  18. Seismic Isolationconstrained layer damped springs AIP Conference

  19. Seismic Isolation AIP Conference

  20. Optics&Suspensions

  21. LIGO requirements Surface uniformity < 1 nm rms Scatter < 50 ppm Absorption < 2 ppm ROC matched < 3% Internal mode Q’s > 2 x 106 Core Opticsfused silica • LIGO measurements • central 80 mm of 4ITM06 (Hanford 4K) • rms  = 0.16 nm • optic far exceeds specification. Surface figure = / 6000 AIP Conference

  22. Seismic Isolationsuspension system suspension assembly for a core optic • support structure is welded tubular stainless steel • suspension wire is 0.31 mm diameter steel music wire • fundamental violin mode frequency of 340 Hz AIP Conference

  23. Core Optics installation and alignment AIP Conference

  24. Laser&Mode Cleaner

  25. LIGO laser • Nd:YAG • 1.064 mm • Output power > 8W in TEM00 mode AIP Conference

  26. Deliver pre-stabilized laser light to the 15-m mode cleaner Frequency fluctuations In-band power fluctuations Power fluctuations at 25 MHz Laserstabilization Tidal Wideband 4 km 15m 10-Watt Laser Interferometer PSL IO • Provide actuator inputs for further stabilization • Wideband • Tidal 10-1 Hz/Hz1/2 10-4 Hz/ Hz1/2 10-7 Hz/ Hz1/2 AIP Conference

  27. Prestabilized Laserfrequency noise • Simplification of beam path external to vacuum system eliminates peaks due to vibrations • Broadband noise better than spec in 40-200 Hz region AIP Conference

  28. Pre-stabilized Laser laboratory data vs e2e simulation AIP Conference

  29. Locking the Interferometers

  30. Interferometerlocking 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 AIP Conference

  31. Lock Acquisition AIP Conference

  32. Composite Video LIGO watching the interferometer lock Y Arm Laser X Arm signal AIP Conference

  33. 2 min LIGO watching the interferometer lock Y arm X arm Y Arm Reflected light Anti-symmetricport Laser X Arm signal AIP Conference

  34. E7 Engineering Run

  35. LIGO InterferometersE7 sensitivities AIP Conference

  36. E7 Run SummaryLIGO + GEO Interferometers 28 Dec 2001 - 14 Jan 2002 (402 hr) Coincidence Data All segments Segments >15min 2X: H2, L1 locked 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 + … 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 AIP Conference

  37. Engineering Run detecting earthquakes From electronic logbook 2-Jan-02 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. AIP Conference

  38. 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), ========================================================================= AIP Conference

  39. Detecting the Earth Tides Sun and Moon AIP Conference

  40. 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 AIP Conference

  41. Commissioning Status for S1 Science Run AIP Conference

  42. LHO 2 km InterferometerStatus • 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 AIP Conference

  43. Interferometer sensitivity history AIP Conference

  44. 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 AIP Conference

  45. Interferometer sensitivity history AIP Conference

  46. LLO 4 km Interferometerstatus • 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 AIP Conference

  47. Interferometer sensitivity history AIP Conference

  48. 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” AIP Conference

  49. “Chirp Signal”binary inspiral determine • distance from the earth r • masses of the two bodies • orbital eccentricity e and orbital inclination i AIP Conference

  50. Interferometer Data40 m prototype Real interferometer data is UGLY!!! (Gliches - known and unknown) LOCKING NORMAL RINGING ROCKING AIP Conference

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