Some of the "PSL story so far" is in 81193. Code saved to /camilla.compton/Documents/Locklosses/PSL_channels.ipynb
I've plotted H1:PSL-PWR_NPRO_OUT_DQ and H1:PSL-FSS_FAST_MON_OUT_DQ in the 30 seconds and 1 second before each locklosss tagged both IMC and FSS by the lockloss tool.
- Plots before the NPRO swap here and zoomed here. There is large individual glitches, seen by both FSS and the NPRO PWR in an otherwise quiet signal before the NPRO swap.
- Plotted after the NPRO swap here and zoomed here. There is none of these individual glitches after the swap but there is the slower building oscillation in the FSS channel, which is overall noisier.
The FSS oscillations we are seeing now are similar to the FSS_OSCLATION locklosses we saw at the end of O3b (G2201762: O3a_O3b_summary.pdf). Note that the current NPRO is the same NPRO as we used in O3. Is it possible that we fixed the glitches issues but reinstalled a laser with similar issues as we saw in O3b? We could revisit that time period to see if we had similar IMC locking issues then too.
Reminder that the lockloss tool tags "IMC" if the IMC looses lock within 50ms of the arms (ASC_AS_A) and tags "FSS" if H1:PSL-FSS_FAST_MON_OUT_DQ with outside of +/- 3 within 1-5 seconds before the lockloss.
Adding in plots from the end of O3b: 30 seconds and zoomed to 1 second before locklosses tagged FSS. The FSS channel looks simular to after the NPRO swap, but were worse in O3b.
Comparing spectra of the FSS_FAST_MON (calibrated Hz/rtHz), ISS_AOM_DRIVER control signal, and FSS_TPD ref cav trans.
- Green = O3 laser in O4 (2024)
- Red = O3 laser at the end of O3b (2020)
- Blue = O4 original laser
FSS FAST MON looks higher for O3 laser vs. the original O4 laser (maybe this is related to the laser itself?). But ISS spectra of the same O3 laser was noisier in O3 than O4, and similarly the FSS_TPD for the same O3 laser was noisier in O3 than in O4.
