What I did

• Ringdown and doppler measurements
• Injected He gas to raise the temperature

Results

The attached file shows the very preliminary results of the ringdown measurements.
As shown in the figure, the finesse at 134 K, and 165 K is smaller than that of 170 K (judged by my eyeballs).
This might imply that the molecular layer i.e., amorphous ice can desorb around between 165 K and 170 K.

It should be noted that the fitting has not yet done...

Next

• TF measurement of PDH loop

Tomorrow, I will measure the TF of PDH locking loop.
Then I will re-cooling the cavity.
At this moment, the target temperature is 10 K and monitor the behavior of finesse in order to estimate the loss induced by cryogenic molecular layer.
I think this result would provide some implications to the Einstein Telescope.