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  • The Latest from LIGO
    at this venue is quieter by one order of magnitude than that of the Hanford site During TAMA s science data taking period a 20m interferometer originally built at NAOJ for the power recycled Michelson experiment was placed at this site and collected data for coincidence measurement This test demonstrated superior performance thanks to the quiet environment The unique design of LCGT is its use of a cryogenic system to suppress thermal noise Sapphire was chosen for the substrate material because of its optical thermal conductivity and measured high Q values at low temperatures Further research is underway with the collaboration of ICRR KEK and industrial companies After completing the basic research using laboratory scale R D an interferometer with 100m arms and sapphire test masses the Cryogenic Laser Interferometer Observatory CLIO seen in Figure 4 below was constructed at the Kamioka site to test the technology in a realistic environment Figure 4 Cryogenic Laser Interferometer Observatory The CLIO project could successfully operate the 100m interferometer with all mirrors cooled down to 20K degrees Unexpected heat flow had been found but the cause was discovered and the system adjusted to reduce the heat flow CLIO is presently operating at room temperature to improve the performance of the interferometer When the sensitivity reaches the level at which it becomes limited by the room temperature thermal noise the cryogenic system will be turned on again Ensconced in its quiet location CLIO shows superb performance excelling even LIGO and Virgo in the very low frequency region Figure 5 Figure 5 Displacement CLIO Sensitivity Adoption of the cryogenic mirror allows a design such that LCGT sensitivity is limited only by quantum noises shot noise and radiation pressure noise The cryogenic mirror is suspended by sapphire fibers connected to an auxiliary mass which is cooled down to 10K degrees This auxiliary mass is part of a suspension point interferometer and serves to suppress the noise induced by the vibration of the cryogenic system This suspension system is installed in a cryostat and a seismic attenuation system is mounted in the room temperature vacuum chamber over the cryostat The optical configuration chosen uses the resonant sideband extraction RSE method with the power recycling gain of 10 and the arm finesse of 1250 With this design the power going through the input test mass can be kept low and the current design of the cryogenic system can cool down test masses with an input power of 150W The signal bandwidth is regulated to be 230Hz With this configuration the gravitational wave source of coalescence of a 1 4M solar neutron star binary can be detected as far as 257Mpc The first LCGT budget request of 15 billion about 130 million for FY2006 and the second one for FY2007 failed to meet approval in part due to the large restructuring of the Japanese government organization involving fundamental research In December 2006 a letter was sent to GWIC representatives from the Japan Gravitational Wave Committee JGWC This committee is

    Original URL path: http://www.ligo.caltech.edu/~ll_news/07101_news/07101.htm (2015-06-02)
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  • L1 progress
    its viton tipped earthquake stops Staff members began a series of interventions from the control room that became more serious over the following two days as the mirror refused to swing free On May 5 the method of last resort was employed a full vent of the chamber removal of the chamber door and entry into the chamber by garbed personnel above right who manually dislodged the mirror Following chamber closure and a 72 hour pump down the gate valves that isolated the vented region were re opened and interferometer operations were restored Upon returning to science operations the interferometer immediately manifested a sharp improvement in sensitivity that corresponded to a drop in the noise floor between 40 and 100 Hz How did the noise reduction occur One hypothesis suggests that the sticking and dislodging of ITMY along with the resetting of several of its earthquake stops may have changed the static electric fields between the mirror and the stops removing a subtle source of dissipation The photo at left shows three of the stops and a through mirror view of one of the control system s voice coils L1 s sensitivity increase followed two weeks of early April commissioning

    Original URL path: http://www.ligo.caltech.edu/~ll_news/0607a_news/L1_progress.htm (2015-06-02)
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  • The LIGO Web Newsletter - March 2005 Edition
    in LIGO News Comments Welcomed Send them to Dave Beckett Editor e mail address beckett ligo caltech edu Here Is What s Inside LIGO Activities at Hanford Washington LIGO Activities at Caltech California LIGO Hosts Year Long Celebration of 2005 World Year of Physics Caltech 40 Meter Team Locks Advanced LIGO like Prototype Interferometer Pasco High School Science Classes Visit LIGO Hanford The LIGO Laboratory is a national facility for

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0503news/0503main.html (2015-06-02)
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  • The LIGO Web Newsletter - March 2004 Edition
    activities Previously in LIGO News Comments Welcomed Send them to Dave Beckett Editor e mail address beckett ligo caltech edu Here Is What s Inside LIGO Activities at Livingston Louisiana LIGO Activities at Caltech California Hydraulic External Pre Isolator Installation Underway Gravity Waves China Joins the Quest NSF Polar Research Programs Antarctica A December s Journey to the South Pole The LIGO Laboratory is a national facility for gravitational wave

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0403news/0403main.html (2015-06-02)
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  • The LIGO Web Newsletter - May 2004 Edition
    LIGO News Comments Welcomed Send them to David Beckett Editor e mail address beckett ligo caltech edu Here Is What s Inside LIGO Activities at Hanford Washington LIGO Activities at Livingston Louisiana National Astronomy Day Celebrated at LIGO Hanford Observatory LLO Receives Funds for Public Education Program and Exhibits LIGO Activities at Caltech California Gary Sanders To Oversee Design and Development of TMT The LIGO Laboratory is a national facility

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0405news/0405main.html (2015-06-02)
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  • The LIGO Web Newsletter - September 2004 Edition
    Dave Beckett Editor e mail address beckett ligo caltech edu Here Is What s Inside LIGO Activities at Hanford Washington LIGO Activities at Livingston Louisiana LIGO 4 Kilometer Detector Approaches Design Sensitivity Hydraulic External Pre isolation at LIGO Livingston Perseid Meteors Light up the LIGO Night Sky LIGO Activities at Caltech California Peter Saulson Delivers 2004 LIGO Public Lecture Trading the Garden for The City Szabi Marka Moves to Columbia

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0409news/0409main.html (2015-06-02)
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  • The LIGO Web Newsletter - February 2003 Edition
    ll find this newsletter an interesting and valuable source of information about LIGO activities Previously in LIGO News Comments Welcomed Send them to Dave Beckett Editor e mail address beckett ligo caltech edu Here Is What s Inside LIGO Activities at MIT Massachusetts Late Breaking Bulletins LIGO and VIRGO A Whole Lot Less Shakin Going On HEPI Installation Nears Completion Quiet Please Second Science Run Now Underway VIRGO Sees First

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0302news/0302main.html (2015-06-02)
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  • The LIGO Web Newsletter - Spring 2003 Edition
    ll find this newsletter an interesting and valuable source of information about LIGO activities Previously in LIGO News Comments Welcomed Send them to Dave Beckett Editor e mail address beckett ligo caltech edu Here Is What s Inside Advanced LIGO Proposers Conference Stanford University Watson Lecture at Caltech Barry Barish on LIGO Company Reps Gather To Discuss Future SEI Design A LIGO Lecture for an Evening s Enjoyment Students Explore

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0305news/0305main.html (2015-06-02)
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