Ibrahim, Tony, Vicky, Ryan S, Jason
Two screenshots below answering the question of whether the PMC Mixer glitches on its own with FSS and ISS out. It does.
PSL team is having a think about what this implies.
Jason, Ryan, Ibrahim, Elenna, Daniel, Vicky - This test had only PSL + PMC for ~2 hours, from 2024/11/11 23:47:45 UTC to 02:06:14 UTC. No FSS, ISS, or IMC.
Mixer glitch#1 @ 1415406517 - 1st PSL PMC mixer REFL glitches. Again, only PSL + PMC. No FSS, ISS, IMC.
The squeezer was running TTFSS, which locks the squeezer laser frequency to the PSL laser frequency + 160 MHz offset. With SQZ TTFSS running, for glitch #1, the squeezer witnessed glitches in SQZ TTFSS FIBR MIXER, and PMC and SHG demod error signals.
This seems to suggest the squeezer is following real PSL free-running laser frequency glitches? Since there is no PSL FSS servo actuating on the PSL laser frequency.
- also suggests the 35 MHz PSL (+SQZ) PMC LO VCO is not the main issue, since SQZ witnesses the PSL glitches in the SQZ FIBR MIXER.
- also suggests PMC PZT HV is not the issue. Without PSL FSS, any PMC PZT HV glitches should not become PSL laser frequency glitches. Caveat the cabling was not disconnected, just done from control room, so analog glitches could still propagate.
Mixer glitch #2 @ 1415408786. Trends here.
Somehow looks pretty different than glitch #1. PSL-PMC_MIXER glitches are not clearly correlated with NPRO power changes. SQZ-FIBR_MIXER sees the glitches, and SQZ-PMC_REFL_RF35 also sees glitches. But notably the SHG_RF24 does NOT see the glitches, unlike before in glitch #1.
For the crazy glitches at ~12 minutes (end of scope) - the SQZ TTFSS MIXER + PMC + SHG all see the big glitch, and there seem to be some (weak) NPRO power glitches too.
Mixer glitches #3 @ 1415409592 - Trends. Ryan and I are wondering if these are the types of glitches that bring the IMC down? But, checking the earlier IMC lockloss (tony 81199), can't tell from trends.
Here - huge PSL freq glitches that don't obviously correlate with PSL NPRO power changes (though maybe a slight step after the first round of glitches?). But these PSL glitches are clearly observed across the squeezer TTFSS + PMC + SHG signals (literally everywhere).
The scope I'm using is at /ligo/home/victoriaa.xu/ndscope/PSL/psl_sqz_glitches.yaml (sorry it runs very slow).
Thinking about the overall at tests done today, see annotated trends.
- PSL + PMC + FSS + IMC (no ISS) ... bad, IMC lockloss after 1:15 hours even with ISS OFF, 81198. IMC lockloss at 2024/11/11 20:37:44 UTC (1415392682).
- PSL + PMC (no FSS, no ISS, no IMC), Test #1... good? No glitches for 30 minutes. Sheila 81200.
- PSL + PMC + FSS (no ISS, no IMC) ... bad, Ref cav did not stay locked. Many glitches (visible in PMC mixer). Sheila 81200.
- PSL + PMC (no FSS, no ISS, no IMC), Test #2 ... bad this time, Tried again as Sheila suggested. After ~40 min, saw glitch #1 in PMC mixer, in turn witnessed by SQZ TTFSS. Bigger glitch #3 seen after ~1.5 hours (this thread).
- Some glitches have NPRO power glitches, some don't.
- The fact that squeezer TTFSS sees glitches could suggest these glitches are real and related to free-running PSL laser frequency glitches?
- In particular - Glitch #3 (above) has similar peak-to-peak on PSL-PMC_MIXER to what unlocked the IMC in the ISS_OFF test earlier today. Glitch #3 also goes on for longer than #1,2.
