Two issues I'm seeing in these plots  1) The ITMX HWS SLED is degrading faster than previous SLEDs and  2) There is some weirdness going on with the ITMX CO2 flow meter a week and a half ago.

ITMX HWS SLED

The rate of degradation of these sleds is often on the order of roughly 2mW/yr. This is why we can generally get about a year's worth out of each SLED. Comparing the last ITMX SLED and the one that we just installed in May (alog84417), the old SLED decayed at a rate of 2.43mW/yr and the new one is 4.2mW/yr. This is just from making some lines in ndscope, so it's pretty rough, but we can definitey say that it is degrading about 2x as fast as the last SLED (attachment 1). The ITMY SLEDs are a bit more consistent at: previous = 2.7mW/yr and new = 2.2mW/yr.

We saw that on the ITMY SLED this last time around that we were still able to see spherical power changes from lock to lock even with the SLED power reporting 0.5mW, and ring heater changes were tough to see (alog84408). Let's consider 0.5mW to be our limit we can take these, but really it should be before we can't see anything, at our current rate this SLED would finish the run at ~0.3mW. Looks like we will need to swap this one before the end of the run.

ITMX CO2 Flow

In Ryan's alog I noticed that the usual change in flow, as reported by the paddle wheel flow meter on the floor, became much more stable on Sunday Aug. 24th. Looking back over two years (attachment 2), it actually looks like the flow has been unusually unstable since returning from the spring vent, and whatever happened on the 24th brought us back to normal. Being a Sunday, there wasn't much going on (alog86540), we were in the middle of a 40+ hour long lock. Zooming into the event doesn't show the laser doing anything during that time, as if it didn't actually see a change in flow. Not sure what's going on here.