Advanced LIGO subsystems
are the organizational units of the overall project. Follow the links below to view the mission and progress of each subsystem.
Auxiliary Optics | Core Optics |
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Data Acquisition | Data and Computing Systems |
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Facilities Modifications |
Input Optics |
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Interferometer Control |
Pre-Stabilized Laser |
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Seismic Isolation |
Suspensions |
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Advanced LIGO News
Glass Fiber Suspensions Move into Producton
November 2011
To reduce thermal noise in the Advanced LIGO interferometers, project personnel will hang certain 40 kg detector mirrors in quadruple suspensions using a quartet of sub-millimeter thickness glass fibers per mirror. The first glass fiber suspension in a production quad underwent assembly at LIGO Hanford in October/November 2011. The act of suspending the optic with glass fibers was the culmination of a long chain of activities such as the bonding of "ears" (for weld points) onto both the mirror and the third-stage glass mass above it. Other steps included the extrusion of tapered 60-cm silica fibers (0.4 mm minumum thickness), and the use of a carbon dioxide laser to perform the welding of the fiber ends onto the upper and lower ears. Precision surveying at the close of the operation revealed that the freely hanging mirror's vertical position was within the 1 mm of the tolerance set by LIGO. The mirror's angle was within the 2 milliradian tolerance level (roughly four hundred-thousandths of a degree).
Glass fiber suspensions originated within the GEO group at the University of Glasgow. The Glasgow group and their counterparts at the University of Birmingham, all members of the LIGO Scientific Collaboration, hold leading responsibility for the delivery of quadruple mirror suspensions in Advanced LIGO. The glass fiber technology that underwent first implementation in the GEO600 detector became a central focus of the suspension groups in LIGO labs at Caltech and MIT during the years leading up to aLIGO construction. MIT's LASTI facility deployed a noise prototype glass fiber quad that served as the predecessor to the production unit shown in these photos. Each of LIGO's three interfemeters will utilize four glass fiber quad suspensions, a requirement that offers a significant schedule challenge for the assembly teams. LIGO suspension personnel on both sides of the Atlantic remain in close contact; members of the UK groups will make a number of visits to LIGO Hanford and LIGO Livingston as the remainder of aLIGO assembly unfolds between 2012 and 2014.
Image 1: A view of the alignment equipment as seen through the third-stage glass mass
Image 2: Two completed welds. The metal wires suspend the third-stage mass
Image 3: The welds must undergo an isopropanol wipe
Image 4: Fully suspended! The monolith must now be reunited to the reaction chain.
aLIGO News Archive
August 2016 -- LIGO Reports O1 Results
June 2016 -- Another Black Hole Merger
Feburary 2016 -- First Gravitational Wave Detection
November 2015 -- O1 Progress Report
August 2015 -- Final Preparations for the O1 Run
February 2015 -- Hanford's H1 Achieves Two-Hour Lock
July 2014 -- Livingston Commissioning Progress
June 2014 -- Livingston Locks the L1 Interferometer
December 2013 -- Livingston Installs End Station Payloads
September 2013 -- Half-interferometer Test Closes
June 2013 -- DRMI Test at Livingston
May 2013 -- Arm Length Stabilization
November 2012 -- One-arm Test at Hanford
September 2012 -- LIGO Begins Locking Optical Cavities
August 2012 -- Installation of Stray Light Controls
July 2012 -- Small Optic Suspenions Enter L1
April 2012 -- First Cartridges Enter the Vacuum
November 2011 -- Glass Fiber Suspensions in Production
October 2011 -- Continued Suspension Development
July 2011 -- Hanford's H2 Becomes a 4K
May 2011 -- LLO Laser Installation Completed
March 2011 -- Input and Output Tubes Undergo Removal
February 2011 -- New Laser Enclosure Takes Shape
December 2010 -- Initial LIGO Comes Out of the Vacuum
October 2010 -- S6 Yields to Advanced LIGO
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