Camilla, TJ, Georgia
Camilla wrote a handy addition to the CO2 power adjust script, which steps the pico on the CO2 periscope mirror while modulating the CO2 power every 5 minutes. I am running this script overnight on my nomachine session.
The script will do picomotor steps of 2000 every 40 minutes. It will step the x pico motor from -10000 steps to -14000, then it will take the x pico back to -10000, and sweep the y pico from -6000 to 8000. (I updated these steps slightly and commited the changes to the svn).
The script lives at /opt/rtcds/userapps/trunk/tcs/common/scripts/power_adj_scripts/co2_power_adjust_inc_pico.py. We've set it to do chops of 2W of CO2 power. It should be done and back at 0W of CO2 power at Mar 10 2021 15:10:33 UTC, which is 7:10am Pacific.
While this script is running please do not change the pico settings on the TCSXCO2 screen. We need pico #3 to stay selected, the speed to stay at walk, and the pico controller to remain enabled.
While this script is running please leave the interferoemter in single bounce ITMX configuration.
I miscalculated how long the script would take - it was on track to finish earlier than expected. I added some extra steps, so the picos will sweep down to -20000 in x. The script now should finish at Mar 10 2021 14:23:42 UTC.
Attached is a screenshot of the test and results. We are trying to find pico-motor settings that minimize the 5 minute oscillations caused by the CO2 powering OFF/ON(2W).
The best results for Y are around +6000 at t = -6h30. The best results for X are maybe -1600 at -1h30, however the overall trend here is moving a fair bit which seems interesting. Possible that the beam is so misaligned its slowly heating a different part of the optic.
I will move them to this position now, then we can do smaller movements to try and improve this.
This morning the AS_AIR camera (image attached) also looked clipped and fringed again so this could be the reason for the drifting X and Y camera positions. This was with pico settings X -20000, Y +4000 with IFO still in single bounce configuration (SRM, PRM, ITMY misaligned).