Following on from Sheila's alog 77427, checked on VAC trends and OFI temperature around April 22nd.
I checked (maybe a repeat of someone else) that there were no vacuum spikes during the locks when Kappa_C dropped or the locklosses afterwards. Plot of Kappa_ C with VAC channels attached.
Looking at the OFI TEC readbacks during that time, they were significantly noisier than usual during Tuesday maintenance after the 5% optical gain drop, before out alignment shift. Noisy between 6:30am and 4pm. This is before any Tuesday maintenance 77363 or injections start. Plot attached, including zoom out and zoom in. It also happened the May 28th to May 30th.
In 78442, we show that these larger than usual OFI temperature swings on locklosses and powerups so happened May 28th/29th when we adjusted our SRC alignment (SRC 250urad). Is this a sign there is an alignment where we are hitting something in the OFI?