SheilaD, FranciscoL, ThomasS [Remote: LouisD]
Today, we tried to evaluate the effect on H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT from changing H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN. In summary, we were not able to collect enough data and we want to do this again with a quiet IFO.
We used the script KappaToDrivealign.py to change the value of H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN. The script worked as intended but has to round off the the value that it uses to change the drivealign to the digits that EPICS can take. H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN changed from 184.65 to 186.53576 (1.012%). We are chainging the gain to reduce the difference of the model of the actuation function and the measurement of \DeltaL_{res}. We did not change H1:CAL-CS_DARM_FE_ETMX_L3_DRIVEALIGN_L2L_GAIN because that would have a net-zero change between measurement and model. We were not able to assess the effect of our change at the end of the commissioning period so we reverted our changes.
kappa_tst_crossbar.png shows a trend of the channels we are concerned of. The crossbar on KAPPA_TST shows that the value drops closely after the gain of DRIVEALIGN_L2L was reverted. However, the uncertainty from H1:CAL-CS_TDEP_PCAL_LINE3_UNCERTAINTY increased during these values, which makes them less reliable. The data between the vertical dashed lines on KAPPA_TST from kappa_tst_deltat.png shows that there was a period of time at which KAPPA_TST was closer to 1 along with a lower uncertainty of PCAL_LINE3.
There are two ways we could repeat this measurement: With 25 minutes of quiet time of the interferometer, we can monitor the changes of KAPPA_TST after changing DRIVEALIGN_L2L gain *or* we can measure simulines before and after changing DRIVEALIGN_L2L. The latter method would illustrate better the sability of the UGF, but it would take around 40 minutes.
To recap the data we collected today was not reliable enough because it had a high uncertainty and it was not enough time to clearly see the effect of our changes. We will try again by either monitoring KAPPA_TST or running simuline measurements.
