LIGO Document T1100165-v2

AOS SLC Manifold/Cryopump and Mode Cleaner Tube Baffles FDR

Document #:
LIGO-T1100165-v2
Document type:
T - Technical notes
Other Versions:
Abstract:
AOS SLC Manifold/Cryopump and Mode Cleaner Tube Baffles FDR
Notes and Changes:
mechanical and optical interface sections and calculations added: see sec 2.7, 3.3.
Updated V2 added with corrected revision number on some pages

2016-10-22 comments by Dennis Coyne:
This Final Design Document (FDD) does not explain why we have the vertical, circular sector, plate at the bottom of the aperture of the Manifold/Cryopump Baffle weldment (MCB) assembly, D1002061. This element was added late in the design in order to block small angle scatter from the far TM which would otherwise pass below the Arm Cavity Baffle (ACB), e.g. D1200578, and scatter from the TCS relay mirror, BSC flooring and other structures. We could not have increased the length of the ACB for the following reasons:

1) Access past the TM into the manifold tube would have been impossible with a longer ACB without ACB removal. In the current arrangement one can crawl under the baffle.

2) Access to the TM HR face is afforded by swinging the ACB back into the manifold and latching it up. This would not be possible with a longer ACB.

3) The shorter ACB permits a TCS CO2 laser beam path from the lower viewports at the Manifold Tube reducer ring to a relay mirror in the ITM BSC chambers. This path was ultimately not used, but was under consideration at the time we were finalizing the ACB and MCB designs.

For sketches related to these considerations, see T1000173-v3, "CO2 Laser Beam Path Considerations for the Thermal Compensation System".


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