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|
|Data Acquisition||Data and|
Advanced LIGO News
LIGO Personnel Rehearse Ear Bonding for Large Optics
A handful of LIGO personnel from the U.K. and U.S. gathered in September to perfect one of the many high-precision skills needed for Advanced LIGO mirror installation -- the bonding of "ears" to the sides of an optic (mirror). Practicing on a fused silica blank of the same dimensions as an aLIGO large optic, members of the team used a hydroxy catalysis process to attach fused silica ears to the blank then verify the integrity of the attachments. The team also gained experience using a large optic "ergo arm" to manipulate the blank. At 40(+) kilograms of mass (roughly 100 pounds), the aLIGO optics are heavy enough to require the ergo arm for movement and positioning.
An aLIGO large optics will hang in its suspension from four glass fibers that cannot be mated directly to the optic's curved sides. The ears offer a surface of suitable geometry for the fiber attachments. An ear is visible in the high-resolution photograph from the May 2010 news note. The ear is the lowest protruding structure, not to be confused with the pair of frosted standoffs above. A single ear provides two attachment points. The bonding process seamlessly joins the ear to the optic. An ear must be aligned with extraordinary precision and its placement must be highly reproducible from one side of an optic to the other and from one mass to another.
Photos courtesy of Marielle van Veggel
Image 1: Personnel rely on the ergo arm to position the fused silica blank.
Image 2: The blank, ready for ear bonding.
Image 3: Preparation of the bonding catalyst
Image 4: A close-up of an ear shows the fiber mating surface.
Image 5: A jig is used for precise positioning of the ear.
Image 6: Inspection of a bond.
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