I saw in Corey's alog this morning that he switched SEI_DIFF to CORNER_DIFF_CPS, I'm guessing because he was having problems and it was a button he could try. It's been in that state ever since, which I think is not the right setting. In the past the FULL_DIFF has caused scattering during high microseism, but I'm looking at data that suggests that is not as much of a problem since we added the R0 tracking on the 14th of this month. Still mining data, so I don't have anything to post right now.
In the meantime, Camilla has transitioned back to FULL_DIFF_CPS at 0:33:32 UTC. This didn't drop us out of OBSERVE, I didn't notice any glitches during the transition.
The surf forecast kind of indicates we may have higher microseism over the next couple of days, so I'd like to ask that we leave SEI_DIFF alone, unless there is very good reason to think it is causing a problem. We could really use a good chunk of time with ~1 micron/s microseism with FULL_DIFF_CPS to see if scattering is still a problem or not.
It's been kind of hard to find segments to compare, with moderate-high microseism, the three attached screens are the best I've found so far. But I think that by looking at the OAF Range integrand blrms, we can say that the R0 tracking has improved the 20-50hz scattering enough that we shouldn't have to change SEI_DIFF, when the microseism is higher.
3 attached plots are 5hr timeseries for different of the 20-29hz & 38-60 range blrms, the ITMY Z .1-.3hz gnd blrms and the R0 L2 drive (indicating if the R0 tracking is on).
First image is from a lock with no R0 tracking and full cps diff on. The top suplot shows a lot of glitching (20-29 hz RLP is high) throughout the 5 hour segment here. Second subplot doesn't show a lot of extra glitching. Third subplot is the microseis for this segment, average value is about 600nm/s.
Second image is for a lock segment with full diff cps on and R0 tracking. Similar microseism, but the top subplot shows a lot less activity. It's subtle, but even the 38-60hz shows less activity with the R0 tracking on.
Third image is with corner diff cps and R0 tracking. The 20-29hz glitching looks about the same as the full diff. R0 tracking was on, similar microseism again. Not a whole lot of difference from the full diff cps with R0 tracking.
I would like some data with higher microseism and FULL_DIFF_CPS on SEI_DIFF, but I think this shows that the R0 tracking has improved the microsesmic scattering.
Sorry about this---I thought I noted somewhere that I made this transition, but looks like I didn't (I blame not being able to get on the network on my laptop last night & then being busy trying to log everything I could for recovery most of the night). I did mention it to Patrick during the hand-off this morning (this node was new to him, and I mentioned the transition, but also that it probably wans't necessary since the microseism was below the 90th percentile. I gave him a brief summary of the node and what it does for us, but that you could also explain it better than I.).
Thanks for catching this!!
QUESTION: We can transition this even when we are in OBSERVING, yes?