hugh.radkins@LIGO.ORG - posted 09:42, Friday 10 March 2017 - last comment - 10:46, Friday 10 March 2017(34725)
PSL Temps correlated to Arm Length, but of course it is!
The attached 5+ day trend plot shows some PSL Table Temp, the LSC drive to HEPI and a lock state indicator.
Clearly the slow warming after the AC ends its rapid cooling or maybe the slow propagation of the cooling effects in the PSL room are seen on the common arm length. Shame, we used to have the Ref Cav 20 C above the room...
The kinks in the Tide signal are not tidal and now that the AC has been disabled, this resulted in the tidal runaway the IFO experienced last night.
Of course, if we reach a new and tolerable steady state, I see no issues running at the higher temp.
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Comments related to this report
The AC is only meant to be enabled whenever personnel are working inside the laser room.
The reason being that whenever personnel are working in there, the HEPA FFUs are supposed
to be on. They generate heat and make it a tad uncomfortable to work in.
Otherwise the Laser Room just inherits whatever the temperature of the LVEA happens to
be (with a small difference due to the make up air fan and the walls).
The reason for the AC turning on otherwise is still a mystery to me at least.