Otabe, Kokeyama, TakahashiR, Itoh(Mirapro), Guiguo, Aso

We took out the OMC from the chamber today to inspect it more in detail.

Procedure

1. Removed the 2-inch steering mirrors on the -Y side of the OMC chamber.
2. Using dog clamps, recorded the current position of the OSTM suspension and the OMC.
3. Locked the OSTM suspension. Removed the cables from the suspension.
4. Moved the OSTM suspension away from the OMC to the -X side of the chamber.
5. Removed the cables from the OMC. Put labels on the disconnected cables. Removed the DC PD driver circuit from the chamber.
6. Locked the OMC suspension, including the blade springs.
7. Removed the OMC from the -Y side of the chamber and put it on a trolley.
8. Wraped the OMC on the trolley with cling wrap.
9. Going around the outside of the clean booth, brought the OMC to the AS table.
10. Put the OMC on the +Y side of the AS optical table.

Starting from the preparation, the extraction operation took about 1.5 hours.

Photos: https://photos.app.goo.gl/BrcZcPKBMJtY7TEe8

Current status

• The OMC is sitting on the AS optical table. We will test it using an NPRO laser on the table.
• The OSTM is back to the original position to serve as an attenuator for the AS beam.
• A beam dump to catch the OSTM reflected beam was installed (not vacuum compatible)
• The steering mirror for the OMC REFL beam was removed from the pillar and put on the bread board because the OSTM reflected beam was hitting the mirror holder.
• To remember the original position of the OMC pillars, we put a dummy plate.
• The attached PDF file shows the current status of the OMC chamber.

OMC inspection

A quick check of the OMC after the extraction did not reveal any obvious problem. No mirror was clearly loose. All the mirrors seemed to be glued properly. We observed some stain on the OMC1 mirror seen from the AR side. However, it is difficult to decide whether it is on the AR surface or on the HR surface.