Keita, Elenna, Louis, Sheila, Oli
It turns out that ETMX IS actually still showing signs of rubbing. We thought we had been in the clear but it looks like we had just found temporary relief from it.
Over the course of trying to lock in the afternoon, ALSX started losing lock more and more frequently in similar looking ways. We couldn't find any quick obvious causes and landed on taking ETMX M0 transfer functions again (reminder that ETMX was looking healthy 2 days ago: 91833). I took an M0 to M0 transfer function measurement with the OPTICALIGN OFFSETs ON, and we saw that we were rubbing >:(. We tried different checks like turning the alignment sliders OFF and ON and eventually we stopped seeing rubbing with the OFFSETs ON (appearently what dislodged it is that we put excitations in the M0 OPTICALIGN filter bank?? I don't remember doing this), but would still see the rubbing when we turned the alignment offsets OFF. This became consistant even while we kept messing with L1 COILOUTF OFFSETs, M0 TEST OFFSETs, and R0 TEST OFFSETs. While we were doing all these tests we were occasionally seeing jolts of movement while ramping stuff on and off, something that I had seen last time and what I imagine is whatever is touching catching an edge on something else before pushing past it.
Keita and I eventually were able to find an offset in R0 Yaw that pulled the LL OSEM away from the LL flag and allowed L1 to swing freely with OFFSETs both ON and OFF. However, when we tried turning the alignment sliders off ~30 minutes later, we found that we were rubbing again even though the R0 Y offset was still on. We also then found that we were now rubbing with the alignment sliders ON, which was strange since we had thought that we had gotten it unstuck when the alignment sliders were ON. Turning R0 Y OFFSET back on did unstick us though, so we are currently free-swinging.
I haven't been able to find definitive proof that ALSX was losing lock because of L1 LL rubbing, though. Looking back through all those short locks, we see that it looks like ALSX DOF2 P (TMSX) seems to grow before we lose lock, but it's not larger than anything that it's able to handle other times during the same locks. This observation also doesn't point to ETMX, but the ETMX channels I looked at didn't show anything that would cause ALSX to drop out.
TF Settings:
- In HEALTH_CHECK, except OPTICALIGN OFFSETs ON in some situations
- DAMP OFF
Table of TFs:
Measurements can be found in $(sustrunk)/QUAD/H1/ETMX/SAG{M0,R0}/Data/
Measurements have been svn'd as: r13143 for M0 and r13143 for R0
| M0 | R0 | |||
| Measurement | OPTICALIGN OFFSETs | TEST Y OFFSET | Rubbing? | Comments |
| 2026-09-10_2145 M0 L | ON | 0 | YES | Rubbing seen on M0 when alignment sliders were ON |
| 2026-09-10_2145 M0 P | ON | 0 | YES | |
| 2026-09-10_2145 M0 Y | ON | 0 | YES | |
| Got L1 LL unstuck for when the OPTICALIGN OFFSETs were ON | ||||
| 2026-09-10_2245 M0 L | ON | 0 | NO | After messing around with different offsets we suddenly were no longer rubbing on M0 when the alignment slider offsets were ON |
| 2026-09-10_2245 M0 P | ON | 0 | NO | |
| 2026-09-10_2300 R0 L | ON | 0 | NO | Not rubbing on R0 either! |
| 2026-09-10_2300 R0 P | ON | 0 | NO | |
| 2026-09-10_2310 R0 L | OFF | 0 | YES | Alignment sliders OFF showed rubbing on R0 |
| 2026-09-10_2310 R0 P | OFF | 0 | YES | |
| 2026-09-10_2342 M0 L | OFF | -25000 | NO | Found the right R0 offset that made it so we were unstuck with alignment sliders both OFF and ON |
| 2026-09-10_2348 M0 L | ON | -25000 | NO | |
In the attached screenshot, the time cursors mark:
You can also see that the temperature trend returns to normal on Sept 4th when the cleanroom was turned off by Jordan: 91821. Looking at the vertical osems you (top row) you can see that the blade springs are slower to return to normal than the room temperature, and have only today returned to where they were before the cleanrooms where turned on.
By adding offsets of -140000 to both M0 and R0 test vertical filter banks I was able to bring the vertical osems back to where they were arounf the time of the TMDS. I took some health check TFs using templates Oli listed above, and clearly still see rubbing even at this similar vertical position to the time of clean TFs.
