louis.dartez@LIGO.ORG - posted 12:32, Friday 31 March 2023 - last comment - 14:19, Friday 07 April 2023(68319)
updated calibration, fixed sign error in L3 path
L. Dartez, J. Kissel We updated the calibration to account for a missed negative sign inH1CAL-CS_DARM_ANALOG_ETMX_L3FM5 (biassign) when I was trying to synchronize the ETMX L2 DriveAlign CAL-CS and SUS models. Correcting for the extra negative bias sign results in the red trace in the attached PCALY2DARM broadband plot . The blue trace is a reference that we took before changing anything with the same settings as I left them in LHO 68306. We're now near unity around 100 Hz and at the 2% level down to 20 Hz. Our list of changes is as follows: -H1:CAL-CS_DARM_ANALOG_ETMX_L1Switch FM7 OFF Switch FM4 ON -H1:CAL-CS_DARM_ANALOG_ETMX_L2Switch FM7 OFF Switch FM4 ON -H1:CAL-CS_DARM_ANALOG_ETMX_L3Switch FM3 ON Switch FM5 and FM7 OFF - ChangeH1:CAL-CS_DARM_FE_ETMX_L3_DRIVEALIGN_L2L_GAINfrom -35.7 to 184.65 - ChangeH1:CAL-CS_DARM_FE_ETMX_L3_LOCK_INBIASfrom -9.3 to 3.3
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TDCF's still cannot be trusted.
Since we've successfully running with the following primary path gain settings for a week, (pulled from the report which informed the sensing and actuation gain values and the cavity pole, LHO:68306) coupled_cavity_optical_gain = 3.337e+06 # [ct/m] (in foton, [the inverse of] this optical gain is written precision at 2.997128735365323e-07 [m/ct]) coupled_cavity_pole_frequency = 441.18 # [Hz] (in foton, this is written with obscene precision at 441.1789008537899 [Hz]) # UIM = 1.61 ==> 7.559e-08 (N/ct) in foton, 7.559040716133722e-08 # PUM = 0.03059 ==> 6.266e-10 (N/ct) in foton, 6.266450556381686e-10 # TST = 2.583e-11 ==> 9.787e-13 (N/ct) in foton, 9.787382864894167e-13 uim_NpA = 1.6100 pum_NpA = 0.03059 tst_NpV2 = 2.583e-11 # Lower than usual because of reduced bias voltage, LHO:67698 So, in the continued process of updating the pydarm parameter file, we need to export the frequency response of the inverse sensing function as calculated by CAL-CS / foton. As per instructions found in LHO:47948, I've exported the foton-computed transfer function of the design string FM1 "TEST_50W_NoD2N" zpk([441.1789008537899],[7000],0.9999999999999997,"n") to the following location: /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Measurements/Foton/ 2023-04-07_H1CALCS_InverseSensingFunction_Foton_TEST_50W_NoD2N_tf.txt and committed it there.