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Status of LCGT and CLIO Masatake Ohashi (ICRR, The University of TOKYO) and LCGT, CLIO collaborators TAUP2007 Sendai, Japan 2007/9/12. Status of LCGT and CLIO Masatake Ohashi (ICRR, The University of TOKYO) and LCGT, CLIO collaborators TAUP2007 Sendai, Japan 2007/9/12. Contents. LCGT Outline

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  1. Status of LCGT and CLIOMasatake Ohashi(ICRR, The University of TOKYO)andLCGT, CLIO collaboratorsTAUP2007Sendai, Japan2007/9/12 Status of LCGT and CLIO Masatake Ohashi(ICRR, The University of TOKYO)andLCGT, CLIO collaboratorsTAUP2007Sendai, Japan2007/9/12

  2. Contents LCGT Outline Status of LCGT Interferometer Design Sapphire Mirror and its Suspension Cryostat and Cooling Technique Status of CLIO Present Status as a proto-type of LCGT Summary TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  3. Large-scale Cryogenic Gravitational wave Telescope （LCGT） 180Mpc illustration: KAGAYA TAUP 2007 Sendai Japan 2007/09/12

  4. LCGT Outline It is 3km Fabry-Perot interferometer with power recycling and broadband RSE. Main mirrors made of sapphire are cooled at 20K. It is built at underground site in Kamioka Mine. Two independent interferometers are installed. The main target is the coalescence of Binary Neutron Starｓ at 180Mpc. TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  5. LCGT on LIGO Web Next generation IFO from Japan TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  6. Merit of Underground site Seismic activity of Kamioka Mine Seismic activity of city area The point is that at least 100m below land surface is necessary to prevent wind effect. Quiet ! TAUP 2007 Sendai Japan 2007/09/12

  7. Interferometer Design TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  8. Interferometer Design- Over View 1 - • Detector parameters • Mirror • Sapphire substrate + mirror coating • Diameter : 25cm • Thickness : 15cm • Mass : 30 kg • Absorption Loss : 20ppm/cm • Temperature : 20 K • Q = 108 • Loss of coating : 10-4 • Final Suspension • Suspension + heat link • with 4 Sapphire fibers • Suspension length : 40cm • Fiber diameter : 1.5mm • Temperature : 16K • Q of final suspension : 108 • Laser • Nd:YAG laser (1064nm) • Injection lock + MOPA • Power : 150 W • Main Interferometer • Broad band RSE configuration • Baseline length : 3km • Beam Radius : 3-5cm • Arm cavity Finesse : 1550 • Power Recycling Gain : 11 • Signal Band Gain : 15 • Stored Power : 771kW • Signal band : 230Hz • Vacuum system • Beam duct diameter : 100cm • Pressure : 10-9 Torr TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  9. Interferometer Design- Over View 2 - Main IFO : 3km IFO Input optics : Two MCs, Modulators, MMT Output optics: OMC, Photo detectors TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  10. Interferometer Design- Layout 1 - 3km arm Center room for IFO-2 Center room for IFO-1 3km arm Two IFOs share the vacuum pipes TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  11. Interferometer Design- RSE - Merit of RSE High-finesse cavity and moderate PRG Easier to realize high power in cavities Smaller transmission light in optics Flexible optimization for GW sources Main reason for LCGT Independent adjustment of power in cavities and signal band Narrow-band observation (optional) Absorption in sapphire substrates Heat absorption : 20ppm/cm x 15 cm = 300 ppm Cooling power : 1W for each mirror Laser power on BS should be less than ~1kW (safety factor 3) TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  12. Sapphire Mirror TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  13. Sapphire Mirror- Absorption - Laser light absorption is important factor for cooling. LCGT requirement : substrate 20ppm/cm (-> 250mW) coating 1ppm (-> 40mW) We need high quality sapphire substrate. TAUP 2007 Sendai Japan 2007/09/12

  14. Sapphire Mirror- Mechanical Quality Factor - Over 108 is obtained TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  15. Sapphire Mirror- Dissipation of the Coating film - Loss Angle Temperature [K] Dissipation is almost independent of Temperature TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  16. Sapphire Mirror- Thermal Expansion - Thermal Expansion Temperature [K] Thermal expansion is negligible at cryogenic temperature. TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  17. Cryogenic Techniques TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  18. Cryogenic Technique- Estimated Heat Generation in the Mirror - Mirror substrate : Sapphire Suspension rods : Sapphire Safety factor ・ Design q=290 mW T=20 K TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  19. Cooling method by a cryocooler TAUP 2007 Sendai Japan 2007/09/12

  20. Seismic Noise Attenuation TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  21. Seismic Attenuation System (SAS) • Inverted pendulum • 30mHz • 3 cascaded GAS filter • 500mHz • Test mass suspension • triple pendulum TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  22. Suspension Point Interferometer (SPI)- Background and Purpose - TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  23. Schedule and Budget 2008 2009 2010 2011 2012 2013 2014 130 M$ without salaryand maintenance LCGT proposal is submitted to the Ministry of Education and Science （MEXT) as one of recommended projects of the University of TOKYO. But LCGT will not start at 2008. We will retry next year. TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  24. CLIO TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

  25. Cryogenic prototype for LCGT TAUP 2007 Sendai Japan 2007/09/12

  26. Overview of CLIO TAUP 2007 Sendai Japan 2007/09/12

  27. Cryostat for an end mirror TAUP 2007 Sendai Japan 2007/09/12

  28. Cooling test and achieved temperature 63K 8.8K 12.9K 45K TAUP 2007 Sendai Japan 2007/09/12

  29. Cooling summary #1; No shield for radiation from the outer shield at 63K. TAUP 2007 Sendai Japan 2007/09/12

  30. Low vibration PT refrigeratorby KEK and SUMITOMO TAUP 2007 Sendai Japan 2007/09/12

  31. Cryogenic suspension TAUP 2007 Sendai Japan 2007/09/12

  32. Heat Transfer 300K Radiation from window of Gate Valve warms mirrors Serious Problem for cooling Mirror (20K) Radiation shield (40K) 300K Radiation ( straying ) Gate Valve (300K) Good Heat Transfer, Baffles, … TAUP 2007 Sendai Japan 2007/09/12

  33. Radiation Shields TAUP 2007 Sendai Japan 2007/09/12

  34. Cooling procedure STEP3 cooling mirror alignment STEP1 cooling mirror alignment STEP4 cooling mirror alignment STEP2 cooling mirror alignment Cooling shortens suspension by 2mm TAUP 2007 Sendai Japan 2007/09/12

  35. Expected Noise Spectrum at 20K Current best (300K) Target sensitivity (300K) Target sensitivity (20K) Resonance of suspension system TAUP 2007 Sendai Japan 2007/09/12

  36. Noise budget for CLIO (300K) Cooling TAUP 2007 Sendai Japan 2007/09/12

  37. Thermal noise reduced by cooling ? Thermal Noise of Aluminum Wires YES ! TAUP 2007 Sendai Japan 2007/09/12

  38. CLIO Stability Akutsu’s POSTER TAUP 2007 Sendai Japan 2007/09/12

  39. SUMMARY We will submit LCGT budget request for FY2009 again next year. Cryogenic prototype CLIO was completed. Now in commissioning phase. We demonstrated to operate interferometer with cryogenic mirrors, but careful heat transfer is necessary for cooling. TAUP 2007 Sendai Japan 2007/09/12

  40. European Plan TAUP 2007 Sendai Japan 2007/09/12

  41. Interferometer Design- Layout 2 - Baffle for LCGT Specification of LCGT Tube diameter 1000mm Mirror diameter 250mm Mirror distance 600mm Mirror offset 340mm - 11 1/2 Seismic motion 1 x 10 m/Hz @30Hz Estimated scattered light noise - 21 1/2 4.2 x 10 m/Hz @30Hz (Safety factor=7) ( for one mirror) Baffle design 1/10 Number: 45x2 for one arm Height: 35~50mm Integration Surface: DLC coatings Diamond - Like Carbon (DLC) coatings Each reflection Surface roughness: Ra=20nm 45 Outgassing : lower than SS316 with baking Reflectivity: 5% for p - polarization at 45deg. TAUP 2007 Sendai Japan 2007/09/12 TAUP 2007 Sendai Japan 2007/09/12

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