FAMIS 20019
Starting Friday afternoon and lasting for about a day, there was a drop in the water temperature for the powermeters' cooling loop of ~0.7 degC and a drop in the return of ~0.2degC. During this time, the signal on the PMC transmitted power PD looked much less noisy (more detailed ndscope screenshot attached). Not sure what exactly caused this, but everything is back to normal as of now.
The FSS RefCav TPD has been holding mostly steady since my alignment tweak Thursday afternoon (alog76199).
All other trends look nominal.
Looking at the PMC noise reduction and drop in cooling water temperature a bit closer, it very clearly lines up with the 20 hour lock over the weekend. This makes sense as more power into the IMC means more heat on the powermeters, so the cooling loop compensated by dropping the water temperature. Since the full IFO was locked, the 4km arms then become the frequency reference, so the PSL FSS did not have to work as hard.
