Summary
I did a first quick round of yaw to length tuning for the test masses. The result is shown below. Still some residual coherence with CHARD_Y, but about a factor 10 improvement.
Details
I wrote a new script to measure and set the A2L coefficients, based on a different procedure. It injects a line in the A2A filter bank and compute the transfer function to DARM. It then injects a line in the A2L filter banks, and again compute the transfer function to DARM. the ratio of the two (taking into account the current A2L coefficient) gives the new A2L coefficients.
The results above were obtained by tuning only YAW for the four test masses, one round for each mirror. The script can be found in
/opt/rtcds/userapps/release/isc/h1/scripts/my_a2l.py
The syntax is straightforward and available from the command line help. The script also saves the results in a place and format compatible with Jenne's spot position scripts.
gabriele.vajente@zotws2:/opt/rtcds/userapps/release/isc/h1/scripts$ python my_a2l.py --help
usage: my_a2l.py [-h] [-m {ITMX,ITMY,ETMX,ETMY}] [-d {P,Y}] [-f FREQUENCY]
[-a AMPLITUDE] [-r RAMP] [-t DURATION] [-n NFFT]
[-s {compute,set}] [-o OUTPUT]optional arguments:
-h, --help show this help message and exit
-m {ITMX,ITMY,ETMX,ETMY}, --testmass {ITMX,ITMY,ETMX,ETMY}
Test mass
-d {P,Y}, --dof {P,Y}
Degree of freedom
-f FREQUENCY, --frequency FREQUENCY
Measurement frequency [Hz]
-a AMPLITUDE, --amplitude AMPLITUDE
Excitation amplitude
-r RAMP, --ramp RAMP Ramp time
-t DURATION, --duration DURATION
Measurement time
-n NFFT, --nfft NFFT Number of points for each FFT
-s {compute,set}, --set {compute,set}
If set to 'set' then actually set the new A2L value,
if set to 'compute' just compute the value
-o OUTPUT, --output OUTPUT
Save result to this folder. Default is /opt/rtcds/user
apps/release/isc/common/scripts/decoup/rec_LHO/
