As a big earthquake came in we just repeated the HWS dither tests but for different actuation node positions (A2L gain changes) to see if we can see the movement on the HWS and also use it to calibrate the magnification of the HWS and what is left/right/up/down. This is a continuation of 66119.
I figure we need to be dithering the L2 stage to see how the A2L gains change the response on the HWS, rather than M0 OPTICALIGN which we were doing last time. I wrote this process up in a script which can just be run hws_dither_test.py, takes about 10 minutes and should be done in a state like PREP_FOR_LOCKING. The code aims to dither the test mass peak to peak about 3urad at 0.05Hz. It dithers ITMX/Y in pitch and yaw separately. The code should be run with a conda enviroment like 'cds'.
Mitchell will atttach some analysis.
FULL_POWER A2L gains:
ITMX_FULL_POWER and ITMY_FULL_POWER.
CENTER A2L gains:
Can't see anything different between the two measurements which is not what we expected. The actuation origins fit exactly the same, and the rotations change by <1 deg.
For reference I have also attached the python script to do this analysis, you will just need to change the GPS times at the start of the script to correspond with the dither measurment times.
The largest move for the actuation center between these two tests is 7.5mm, do we expect to resolve this? We could repeat this during Tuesday maintainence tomorrow with larger a2l gains to see when we can see this movement with the hws.
| Spot is XXmm from the center of the optic at: | FULL_POWER | CENTER | |
| ITMX | PIT | 7.5mm | 0.1mm |
| YAW | 6.3mm | 0.0mm | |
| ITMY | PIT | 4.2mm | 0.1mm |
| YAW | -4.8mm | 0.0mm | |
Using a2l values from Dan's hws_dither_test script and /opt/rtcds/userapps/release/isc/common/scripts/decoup/BeamPosition/a2l_lookup.m