KAGRA MIR (Absorption)
MarcEisenmann - 15:14, Friday 18 March 2022 (2880)
little burning of the holder

This morning I wanted to start a new measurement on the XZ plane.

Before any measurements we need to check the input power so it is convenient to just move the mirror outside the beam.

I made a mistake in the motion and actually could see that the beam was cut somewhere.

I started the measurement to try to see features on the mirror surface but it was not so much conclusive so I went to TAMA and found out that the bottom left of the holder got a little burnt (see picture 1).

After discussing with Matteo, I decrease the pump laser power, closed the shutter and removed the holder from the translation stage.

I inspected the surfaces of the mirror with the strong green light and it seemed to be not too dirty but to avoid any doubts on the measurements results I cleaned them with alcohool, lens cleaning tissue and ion gun.

I also cleaned the holder (see picture 2) and removed dust from the translation stage.

I added more stringent limits on Zaber that should be changed before KAGRA size sample measurements.

The mirror is now reinstalled and I'm waiting for the pump laser power to stabilize before restarting measurements.

Images attached to this report
2880_20220318071351_burn2.jpeg 2880_20220318071359_burn1.jpeg