LIGO Document E1300128-v3

aLIGO Interferometer Optics Positions and Orientations for Initial Alignment

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Document type:
E - Engineering documents
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12 Feb 2013, 15:04
Why another optical layout calculation? The Zemax optical layouts are non-sequential models which are aligned "by hand". The optic positions and orientations are tweaked iteratively by the Zemax user, much as one would align the real interferometer. This results in small positional and angular errors and positional/angular data which change for each new release of the Zemax layout.
This optical layout calculation uses vector analysis in Mathematica, with as-built/assigned optic parameters (not just nominal values) so that it is a definitive source of positional/angular data for the Initial Alignment System (IAS) and calculations of IAS alignment solutions. It also serves as a sanity check on the Zemax optical layouts and IO PRC layouts.

Note that the Zemax layouts reported in D0901920 (H1) and D0902216 (L1) are the sources for positional information for the primary interferometer optics for SolidWorks (CAD), with the exception of the PRC optics (PRM, PR2 and PR3). The PRC optic positions for SolidWorks are defined in the IO documents E1100492 (LHAM2), E1100493 (LHAM3), E1100494 (WHAM2) and E1100495 (WHAM3).

Notes and Changes:
1) Changed length/distance comparisons to T0900043-v11 from the cold case to the nominal design case for 12.5 W of PSL input power.
2) Changed the global positions of the H1 SRM and SR2 HR centers to be consistent with IOís (Luke Williamís) H1 master coordinate list E1200616-v7. The positions of these optics changed based on the as-built radii of curvature (ROC).
3) N.B. : According to the IO H1 Master Coordinates List (E1200616-v7), the center of the HR face of PRM is at {-20193.8, -628.0, -94.2}, or 4.2 mm different in x compared to E1100494-v3 (which has a value of -20189.6)! The E1100494-v3 coordinates were used to position/align the H1 PRM. Leaving as is for now; The ROC measurement is rather uncertain, so it is not clear if this error will need to be corrected or not.
4) At the end of the notebook, I added L1-ITMy and L1-CPy OptLev ghost beam calculations to match measurements and Zemax calculations of the mis-aligned CPy at LLO; see LLO elog #28336

4/7/2015 D. Coyne: Noticed an error in the calculation of the SRM global position for H1. Is correct for L1. Not sure what the consequences might be as yet.

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