TJ had another lockloss around the time of the beam diverters closing this morning, it happened during OMC whitening. Following up on what Jenne and Elenna saw last night 87962 , I looked at HAM1 GS13s during the lockloss.
In the attached screenshot the first time cursor shows when the CLOSE_BEAM_DIVERTERS guardian state ends and the guardian moves on to switching the OMC whitening state, the HAM1 ISI is still shaking from the beam diverters when the OMC DCPD gains are changed. I've saved this template as sheila.dwyer/ndscope/LOCKLOSS/beam_diverter_lockloss_check.yml
I've added a 10 second timer to the close beam diverters state, so that these things will be separated in time.
This didn't seem to work, another lock loss when closing beam diverters.
I rewrote the Close_Beam_Diverters state to close the 3 beam diverters some number of seconds apart. I chose 2 seconds to start with because Sheila had mentioned the the GS13's looked to have settled in about that time. We lost lock 1 second after closing the first beam diverter, the A REFL diverter.
At this point I think we will leave them open, unless some other ideas pop up before we get back to that point.
Jenne, Elenna, TJ, Sheila
There is a small signal in the GS13 (500 counts on H1 INF) when the beam diverter starts moving, about 0.3 seconds before the open switch turns false. Then the large kick (6000 counts) happens 0.3 seconds after the close switch shows that the beam diverter is closed.
Looking at the HAM6 beam diverter, it only has a small (500 counts) kick after the beam diverter closed. Jim tells us that H1 is on the +y -x side of the ISI, so close to the REFL and POP beam diverter in HAM6.
It seems that the REFL beam diverter was the cause of one lockloss, after TJ separated them in time.
Below are screenshots of the sequence of kicks seen by the GS13s when both REFL and POP beam diverters are opened and closed, opening and closing looks very similar. We see the same pattern in HAM6 when moving the AS beam diverter, although with a smaller amplitude. (I attached a screenshot of H1, Elenna looked at all the GS13s in HAM6 and says they are all smaller)
This kind of kick has happened in each lock since the ISI was installed, although it seems to be smaller June 4/5. This didn't cause locklosses until Oct 21st.
Here is the look at all the GS13s in both HAM1 and HAM6.
