Jennie W, Sophie M, Sheila D,

First we checked that the MC mirrors top mass OSEMS matched their position at 00:00 UTC on December 19th. This was the last time when the IMC was locked in air after HEPI was locked on HAM2 before JAC install.

MC1 -678 mrad P, -1365 mrad Y.

Sheila and Sophie went to align in chamber using JAC_M3  (mirror right before JAC HAM1 output periscope) and JM2 (mirror right after JAC).

I looked with the beam card between the upper and lower periscope mirrors at the beam spot.

Sheila and Sophie walked the beam in pitch and the beam started to clip badly. They undid this and Sheila came to check the beam on the table and realised that it looked much dimmer than expected compared to the beam leaving the chamber.

She suggested it might be a ghost beam coming onto the table.

After lunch we checked this with the power metre and we had 40mW into HAM2 but 0.46 mW onto the bottom periscope mirror in IOT2L.

Sophie managed to unclip this mainly with pitch (in the JM2 basis) beam walking, with very slow changes on both mirrors in turn and checking the REFL output and the power onto the table we eventually got ~ 20mW, measured after the bottom periscope mirror.

We eventually made enough change that the beam was getting to both MC REFL WFS but not hitting the diodes.

Sophie did more beam walking in yaw on the two mirrors while looking at MC REFL PD and maximising the power on this. The power metre at the end of the day showed 23 mW just after the lower IOT2L periscope mirror but we were still not hitting the WFS PDs. The beam is low and right on MC REFL WFS B.