Status of the LIGO Project Rick Savage - LIGO Hanford Observatory Future Trends in Cosmic Ray Physics ICRR – Kashiwa, Japan

Future Trends in Cosmic Ray Physics 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

Future Trends in Cosmic Ray Physics 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

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

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

Livingston Observatory 4 km Future Trends in Cosmic Ray Physics

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

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

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

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

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

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

Initial LIGO Sensitivity Goal Strain sensitivity < 3x10-23 1/Hz1/2 at 200 Hz Displacement Noise Seismic motion Thermal Noise Radiation Pressure Sensing Noise Photon Shot Noise Residual Gas Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics 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 2-year initial data run Schedule: Begin installation: 2005 Begin data run: 2007 Future Trends in Cosmic Ray Physics

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

Future Trends in Cosmic Ray Physics Design Sensitivity h (1/ Hz1/2) Future Trends in Cosmic Ray Physics

Initial LIGO Detector Status Construction project - Finished Facilities, including beam tubes complete at both sites Detector installation Washington 2k interferometer complete Livingston 4k interferometer complete Washington 4k interferometer in progress Interferometer commissioning Just getting underway at Livingston Washington 2k well under way First astrophysical data run - 2002 Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics Beam Tubes Type 304 SS Special processing to reduce hydrogen outgassing 1.2 m diameter 3 mm thick Spiral welded in 20 m lengths Over 50 km of welds NO LEAKS ! GPS alignment within 1 cm LN2 and Ion pumps at 2 km intervals only Serrated SS baffles to control scattered light Future Trends in Cosmic Ray Physics

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

Future Trends in Cosmic Ray Physics Bake Results Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics Vacuum Equipment Future Trends in Cosmic Ray Physics

Vibration 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 Future Trends in Cosmic Ray Physics

Seismic Isolation – Springs and Masses damped spring cross section Future Trends in Cosmic Ray Physics

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

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

Core Optics Suspension and Control Future Trends in Cosmic Ray Physics

Core Optics Installation and Alignment Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics Pre-stabilized Laser 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 IO 10-Watt Laser PSL Interferometer 15m 4 km Tidal Wideband 10-1 Hz/Hz1/2 10-4 Hz/ Hz1/2 10-7 Hz/ Hz1/2 Future Trends in Cosmic Ray Physics

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

WA 2k Pre-stabilized Laser Performance > 18,000 hours continuous operation Frequency and PMC lock very robust TEM00 power > 8 watts Non-TEM00 power < 10% Future Trends in Cosmic Ray Physics

Interferometer Sensing and Control Length Sensing and Control Reflection locking technique length and frequency sensing Control 4 longitudinal degrees of freedom and laser frequency Requirements: Differential arm length <10-13 m rms Frequency noise < 3x10-7 Hz/Hz1/2 at 100 Hz Controller noise for diff. arm length <10-20 m/ Hz1/2 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

Interferometer Optical Layout Future Trends in Cosmic Ray Physics

Control and Data Systems Gravitational waves Strain Interferometer Seisms Common mode signals Laser Fluctuations Alignment signals Thermal Noise Acoustic signals Electromagnetics Seismometer signals 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

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

Confirmation of Initial Alignment beam spot Opening gate valves revealed alignment “dead reckoned” from corner station was within 100 micro radians Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics Locking the Long Arm 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 First interference fringes from the 2-km arm Future Trends in Cosmic Ray Physics

Activation of Wavefront sensors Alignment fluctuations before engaging wavefront sensors After engaging wavefront sensors Future Trends in Cosmic Ray Physics

Long Arm Stretching Due to Earth Tides 10 hour locked section Stretching consistent with earth tides Future Trends in Cosmic Ray Physics

Near-Michelson interferometer Power-recycled (short)Michelson Interferometer - Full mixed digital/analog servos Interference fringes from the pwr-recycled near-Michelson interferometer Future Trends in Cosmic Ray Physics

Locking the Complete Interferometer Interferometer lock states Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics Brief Locked Stretch Y arm X arm Reflected light Anti-symmetric port Future Trends in Cosmic Ray Physics

End-to-End Modeling of Locking Process Hanford 2k Model Arm cavities Anti-symmetric port Modeled locking transient Impulse applied to end mass Future Trends in Cosmic Ray Physics

Future Trends in Cosmic Ray Physics Summary Livingston Observatory 4-km interferometer installed commissioning underway Hanford Observatory 2-km interferometer installed commissioning underway 4-km installation underway 2001 Commission Hanford 4-km interferometer Engineering runs to improve strain sensitivity First coincidence operation Improve reliability and sensitivity 2002 Begin first astrophysics data run Hanford Observatory control room Future Trends in Cosmic Ray Physics