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
Initial LIGO Input and Output Tubes Undergo Removal
March 2011
Photos courtesy of Rodney Haux
A LIGO interferometer forms the familiar enormous "L," but each segment of the L projects for two dozen meters on the opposite sides of the vertex where the beam splitter rests. One of these projections forms the input side of the detector; laser light approaches the beam splitter along this line. The perpendicular output line carries the interference pattern downstream from the beam splitter to the sensing photodiodes. On the input side, Initial LIGO (iLIGO) laser light entered the vacuum from the PSL and traveled through a mode cleaner cavity and a set of mode-matching telescopes that increased the beam diameter. The light then passed through a power recycling mirror before reaching the beam splitter. The path on the output side was simpler, although it became more complex in Enhanced LIGO due to the insertion of an output mode cleaner in the terminal chamber along the output line.
Advanced LIGO (aLIGO) will employ input and output (IO) beam paths of greater complexity. The sizes of aLIGO optics and their suspensions along these paths will increase in comparison to similar iLIGO parts. The IO beams themselves will increase in diameter over iLIGO. These changes will require beam tube segments of greater diameter along the IO beam lines. The photos below show the removal of an Initial LIGO output tube segment to make way for its wider replacement. The length of the tube created several challenges for the extraction crews as they craned the unit through the Laser Vacuum and Equipment Area (LVEA). Approximately 3000 pounds, the tube eventually made its way outside the building then off-site for recycling. The new tubes will arrive from the manufacturer clean and baked and ready for installation once received at the Observatories.
Image 1: View of the H2 output tube looking towards the beam splitter.
Image 2: Loosening the O-ring.
Image 3: Sliding in the temporary chamber cover.
Image 4: This HAM chamber will wait for the new tube.
Image 5: The view from 90 deg clockwise. The H2 input tube appears on the right.
Image 6: The tube on its way out of the LVEA.
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
Explore Advanced LIGO
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