[Jim, Shoshana]
The CRS is currently aligned, suspended, balanced, and unlocked on HAM3!
I aligned each HoQI as well as I could on the table, HoQI2 is slightly better than HoQI1, but it shouldn't be an issue. I also lowered the resonant frequency as much as possible, but I ended up running out of mass that I could easily remove from the bottom, so right now the resonant frequency is at ~25Hz. It's possible this raised frequency is because these flexures (21, 22) might be slightly thicker than the previous ones as they came from a different batch.
Tested the picomotor, moving the X value positive moves the mass to the left (towards HoQI1). We had it do three revolutions in both directions and the picomotor was able to couple with the mass adjuster while at maximum range (tilting fully to either side). We've also discovered that the GS13s outputs go crazy when the picomotor is running, which is something to be aware of.
We've verified that voltage makes it to the damping capacitor plates on either side. We've also confirmed that in the HOQI{1,2}_DIST data increases as the corner cube gets closer to either interferometer (i.e. when the left corner cube (wing) gets closer to HoQI1, the HoQI1_DIST channel data increases)
Attached are various photos of the CRS on the table for future reference, as well as a guide to all the balance masses currently on it.
Notes on CRS commissioning tonight :
- The CRS DISP2ANG matrix was reset to the right values to convert HOQI distance readout to tilt (fig 1). The hoqi readout is in um and the tilt readout is in urad.
- The HOQI ellipse was fitted using the script below and coefficients were pushed to the frontend (sdf saved) (fig 2, fig 3)
/opt/rtcds/userapps/release/isi/h1/scripts$ ./write_ellipse_values3.py - The CRS damping (using ISI actuators) was comissioned and works well to damp the crs (see fig 4 around -8min when the damping is turned on). The settings are shown attached in fig 5
- An initial 1mHz Ry to Ry transfer function was measured, using this template. A screenshot of the template is shown on fig 6. The coherence is not great below the resonant frequency so a new measurement was started and will run overnight. The CRS response was normalized to the CPS response and fitted to the zpk parameters below (see pdf 1)
zpk([0.0027 + 0.0749i 0.0027 - 0.0749i],[0.0013 + 0.1597i 0.0013 - 0.1597i],1.0214)
All data and scripts are attached - Finally the Q was measured from a 3 hour ring-down starting at gps 1467499281- below are the parameters (see also fig 7)
- Natural Frequency: 0.0253 Hz
- Time Constant (tau): 5011.7800 s
- Quality Factor (Q): 398.00
