Status of the LIGO Project

1. Status of the LIGO Project Rick Savage - LIGO Hanford Observatory Future Trends in Cosmic Ray PhysicsICRR – Kashiwa, Japan

2. Outline of Talk • LIGO Organization • LIGO Laboratory • LIGO Science Collaboration • Performance Goals • Initial LIGO • Advanced LIGO • Detector Installation • Detector Commissioning Future Trends in Cosmic Ray Physics

3. LIGO Organization • Collaboration between California Institute of Technology (Caltech) and the Massachusetts Institute of Technology (MIT) • Funded by the National Science Foundation • LIGO Laboratory • Caltech, MIT, Hanford Observatory, Livingston Observatory • LIGO Scientific Collaboration • Twenty six member institutions • Commissioning of the initial detector • Data Analysis • Design of Advanced LIGO Future Trends in Cosmic Ray Physics

4. HANFORD Washington MIT Boston 3 0 3 ( 0 ± 1 k 0 m m s ) CALTECH Pasadena LIVINGSTON Louisiana LIGO Observatories Future Trends in Cosmic Ray Physics

5. Hanford Observatory 4 km 2 km Future Trends in Cosmic Ray Physics

6. Livingston Observatory 4 km Future Trends in Cosmic Ray Physics

7. Global Network of GW Detectors Virgo GEO LIGO TAMA (LCGT) AIGO Future Trends in Cosmic Ray Physics

8. GW Detectors … AIGO Australia GEO 600 Germany Virgo Italy Future Trends in Cosmic Ray Physics

9. … GW Detectors TAMA 300 Sensitivity – Best Ever! TAMA 300 Japan LCGT - Kamioka Future Trends in Cosmic Ray Physics

10. SOURCE SOURCE GEO TAMA VIRGO LIGO Hanford LIGO Livingston SOURCE SOURCE DL = c dt q 1 2 Event Localization with Array of Detectors Dq ~ c dt / D12 Dq ~ 0.5 deg Future Trends in Cosmic Ray Physics

11. Global Network – Joint Data Analysis • Protocols being established by GWIC (Gravitational Wave International Committee) • Commonality of data • Formats • Reduced data sets • Standards for software, validation techniques • Techniques to combine data from the elements of a network for different types of searches • Event lists (first pass) • Phase-coherent processing (second pass) • Shared computational resources and facilities • Concepts for a common publication policy • Concepts for establishing astronomical alerts Future Trends in Cosmic Ray Physics

12. Initial LIGO Interferometers Power Recycled Michelson Interferometer with Fabry-Perot Arm Cavities end test mass 4 km (2 km) Fabry-Perotarm cavity recycling mirror input test mass Laser beam splitter signal Future Trends in Cosmic Ray Physics

13. Initial LIGO Sensitivity Goal • Strain sensitivity < 3x10-23 1/rtHzat 200 Hz • Displacement Noise • Seismic motion • Thermal Noise • Radiation Pressure • Sensing Noise • Photon Shot Noise • Residual Gas Future Trends in Cosmic Ray Physics

14. Advanced LIGO • Now being designed by the LIGO Scientific Collaboration • Goal: • Quantum-noise-limited interferometer • Factor of ten increase in sensitivity • Factor of 1000 in event rate. One day > entire initial LIGO data run • Schedule: • Begin installation: 2005 • Begin data run: 2007 Future Trends in Cosmic Ray Physics

15. Interferometer Concept • Signal recycling • 180-watt laser • Sapphire test masses • Quadruple suspensions • Active seismic isolation • Active thermal correction • DC readout scheme? Future Trends in Cosmic Ray Physics

16. h / rtHz Design Sensitivity Future Trends in Cosmic Ray Physics

17. Initial LIGO Detector Status • Construction project • Facilities, including beam tubes complete at both sites • Within budget and on schedule • Detector installation • Washington 2k interferometer complete • Livingston 4k interferometer complete • Washington 4k interferometer in progress • Interferometer commissioning • Just getting underway at Livingston • Washington 2k single arm test complete • WA 2k interferometer locking in progress • First astrophysical data run - 2002 Future Trends in Cosmic Ray Physics

18. Beam Tubes • Type 304 ss • Special processing to reduce hydrogen outgassing • 1.2 m diameter3 mm thick • Spiral welded in 20 mlengths • Over 50 km of welds • NO LEAKS ! • GPS alignment within 1 cm • LN2 pumps at ends only • Serrated ss baffles to control scattered light Future Trends in Cosmic Ray Physics

19. Beam Tube Vacuum Bake Future Trends in Cosmic Ray Physics

20. Bake Results Future Trends in Cosmic Ray Physics

21. Vacuum Equipment Future Trends in Cosmic Ray Physics

22. Vibration Isolation Systems • Reduce in-band seismic motion by 4 - 6 orders of magnitude • Attenuate microseism at 0.15 Hz by a factor of ten • Compensate (partially) for Earth tides Future Trends in Cosmic Ray Physics

23. damped springcross section Seismic Isolation – Springs and Masses Future Trends in Cosmic Ray Physics

24. 102 100 10-2 10-6 Horizontal 10-4 10-6 10-8 Vertical 10-10 Seismic System Performance HAM stack in air BSC stackin vacuum Future Trends in Cosmic Ray Physics

25. Surface uniformity < 1 nm rms Scatter < 50 ppm Absorption < 2 ppm ROC matched < 3% Internal mode Q’s > 2 x 106 Core Optics Caltech data CSIRO data Future Trends in Cosmic Ray Physics

26. Core Optics Suspension and Control Future Trends in Cosmic Ray Physics

27. Core Optics Installation and Alignment Future Trends in Cosmic Ray Physics

28. Deliver pre-stabilized laser light to the 15-m mode cleaner Frequency fluctuations In-band power fluctuations Power fluctuations at 25 MHz Tidal Wideband 4 km 15m 10-Watt Laser Interferometer PSL IO Pre-stabilized Laser • Provide actuator inputs for further stabilization • Wideband • Tidal 10-1 Hz/rtHz 10-4 Hz/rtHz 10-7 Hz/rtHz Future Trends in Cosmic Ray Physics

29. Washington 2k Pre-stabilized Laser Future Trends in Cosmic Ray Physics

30. WA 2k Pre-stabilized Laser Performance • > 18,000 hours continuous operation • Frequency and PMC lock very robust • TEMoo power> 8 watts • Non-TEMoo power< 10% Future Trends in Cosmic Ray Physics

31. Interferometer Sensing and Control • Length Sensing and Control • Monolithic photodetectors (Pound-Drever-Hall sensing) • Control 4 longitudinal degrees of freedom and laser frequency • Requirements: • Differential arm length <10-13 m rms • Frequency noise < 3x10-7 Hz/rtHz at 100 Hz • Controller noise for differential arm length <10-20 m/rtHz at 150 Hz • Alignment sensing and control • Wavefront sensors (split photodetectors) • Digital Control of 12 mirror angles and the input beam direction • Requirement: angular fluctuations < <10-8 rad rms Future Trends in Cosmic Ray Physics

32. Interferometer Optical Layout Future Trends in Cosmic Ray Physics

33. Control and Data Systems Strain Gravitational waves Interferometer Common mode signals Seisms Alignment signals Laser Fluctuations Acoustic signals Thermal Noise Seismometer signals Electromagnetics • All interferometric detector projects have agreed on a standard data format • Anticipates joint data analysis • LIGO Frames for 1 interferometer are ~3MB/s • 32 kB/s strain • ~2 MB/s other interferometer signals • ~1MB/s environmental sensors Future Trends in Cosmic Ray Physics

34. Detector Commissioning: 2-km Arm Test • 12/99 – 3/00 • Alignment “dead reckoning” worked • Digital controls, networks, and software all worked • Exercised fast analog laser frequency control • Verified that core optics meet specs • Long-term drifts consistent with earth tides Future Trends in Cosmic Ray Physics

35. Confirmation of Initial Alignment • Opening gate valves revealed alignment “dead reckoned” from corner station was within 100 microradians Future Trends in Cosmic Ray Physics

36. 12/1/99 Flashes of light 12/9/99 0.2 seconds lock 1/14/00 2 seconds lock 1/19/00 60 seconds lock 1/21/00 5 minutes lock(on other arm) 2/12/00 18 minutes lock 3/4/00 90 minutes lock(temperature stabilized laser reference cavity) 3/26/00 10 hours lock Locking the Long Arm Future Trends in Cosmic Ray Physics

37. Activation of Wavefront sensors Alignment fluctuationsbefore engagingwavefront sensors After engagingwavefront sensors Future Trends in Cosmic Ray Physics

38. Long Arm Stretching Due to Earth Tides 10 hour locked section Stretching consistentwith earth tides Future Trends in Cosmic Ray Physics

39. Near-Michelson interferometer Power-recycled (short)Michelson Interferometer - Full mixeddigital/analogservos Future Trends in Cosmic Ray Physics

40. Locking the Complete Interferometer Future Trends in Cosmic Ray Physics

41. Summary LIGO Hanford: • tests of laser and mode cleaner summer/fall 1999 • “first lock” down one arm fall 1999 • complete installation/commissioning of 2K and 4K IFOs 2000 LIGO Livingston: • Complete optics suspension & installation 2000 • complete installation and commissioning of 4K IFO 2000 Simultaneous operation: • Engineering run to improve strain sensitivity 2001 • first coincidence operation 2001 • Improve reliability and sensitivity 2001 • First Astrophysics Run 2002 • Expect uptime > 50% over 2 years operating at hRMS~10-21 PHOTO OF CONTROL ROOM Future Trends in Cosmic Ray Physics