francisco.llamas@LIGO.ORG - posted 17:17, Tuesday 01 July 2025 - last comment - 17:07, Monday 14 July 2025(85487)
PCAL EX Measurement
DriptaB, FranciscoL, TonyS
Measurement summary:
Resumed routine end station measurement post O4c comissionning break. Procedure following T1500062 went smoothly. The beams as found are shown in the first attached image, were both pcal beams are shown in the IR card. The beam target was placed to have a reference of the "center" of the input aperture. The second attached image shows both pcal beams after the measurement procedure, showing no change in alignment. Forgot to use target and was under a time crunch to finish procedure. Results are nominal -- there are no outliers found on the plotted trends. We thus conclude, from the reported measurement, no need to update EPICS values for PCAL X "Force coeff. calculation".
Terminal output from data analysis script:
$python3 generate_measurement_data.py --WS PS4 --date 2025-06-24Reading in config file from python file in scripts../../../Common/O4PSparams.yamlPS4 rho, kappa, u_rel on 2025-06-24 corrected to ES temperature 299.2 K :-4.70052522573445 -0.0002694340454223 2.66508565972755e-05Copying the scripts into tD directory...Connected to nds.ligo-wa.caltech.edumartel runreading data at start_time: 1435423390reading data at start_time: 1435423770reading data at start_time: 1435424085reading data at start_time: 1435424665reading data at start_time: 1435425020reading data at start_time: 1435425335reading data at start_time: 1435425435reading data at start_time: 1435426070reading data at start_time: 1435426405Ratios: -0.46199911560110457 -0.4661225769446798writing nds2 data to filesfinishing writingBackground Values:bg1 = 9.235188; Background of TX when WS is at TXbg2 = 5.284960; Background of WS when WS is at TXbg3 = 9.145166; Background of TX when WS is at RXbg4 = 5.413446; Background of WS when WS is at RXbg5 = 9.219525; Background of TXbg6 = 0.642557; Background of RXThe uncertainty reported below are Relative Standard Deviation in percentIntermediate RatiosRatioWS_TX_it = -0.461999;RatioWS_TX_ot = -0.466123;RatioWS_TX_ir = -0.455904;RatioWS_TX_or = -0.461457;RatioWS_TX_it_unc = 0.092717;RatioWS_TX_ot_unc = 0.098001;RatioWS_TX_ir_unc = 0.097458;RatioWS_TX_or_unc = 0.092076;Optical EfficiencyOE_Inner_beam = 0.986610;OE_Outer_beam = 0.990080;Weighted_Optical_Efficiency = 0.988345;OE_Inner_beam_unc = 0.062698;OE_Outer_beam_unc = 0.063147;Weighted_Optical_Efficiency_unc = 0.088986;Martel Voltage fit:Gradient = 1636.767545;Intercept = 0.229197;Power Imbalance = 0.991154;Endstation Power sensors to WS ratios::Ratio_WS_TX = -1.077445;Ratio_WS_RX = -1.391120;
Ratio_WS_TX_unc = 0.058121;Ratio_WS_RX_unc = 0.042422;
========================================================================== Values for Force Coefficients ==============================================================================
Key Pcal Values :GS = -5.135100; Gold Standard Value in (V/W)WS = -4.700525; Working Standard Value
costheta = 0.988362; Angle of incidencec = 299792458.000000; Speed of LightEnd Station Values :TXWS = -1.077445; Tx to WS Rel responsivity (V/V)sigma_TXWS = 0.000626; Uncertainity of Tx to WS Rel responsivity (V/V)RXWS = -1.391120; Rx to WS Rel responsivity (V/V)sigma_RXWS = 0.000590; Uncertainity of Rx to WS Rel responsivity (V/V)
e = 0.988345; Optical Efficiencysigma_e = 0.000879; Uncertainity in Optical Efficiency
Martel Voltage fit :Martel_gradient = 1636.767545; Martel to output channel (C/V)Martel_intercept = 0.229197; Intercept of fit of Martel to output (C/V)
Power Loss Apportion :beta = 0.998895; Ratio between input and output (Beta)E_T = 0.993606; TX Optical efficiencysigma_E_T = 0.000442; Uncertainity in TX Optical efficiencyE_R = 0.994705; RX Optical Efficiencysigma_E_R = 0.000443; Uncertainity in RX Optical efficiency
Force Coefficients :FC_TxPD = 7.903342e-13; TxPD Force CoefficientFC_RxPD = 6.193451e-13; RxPD Force Coefficientsigma_FC_TxPD = 5.805084e-16; TxPD Force Coefficientsigma_FC_RxPD = 3.826232e-16; RxPD Force Coefficientdata written to ../../measurements/LHO_EndX/tD20250701/
Images attached to this report
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Comments related to this report
Comment regarding the missing signal on the EX Pcal MEDM:
We noticed that H1:CAL-PCALX_OFS_DRIVE_MON was not working as expected a few weeks ago. On this expedition to make ES measurements, Dripta and I used a few breakout boards to ensure that the "OFS drive monitor" signal was coming out of the Pcal chassis and into the ADC Chassis. We confirm that there was a signal coming out of the Pcal Interface Chassis back board (D1400149V1), the DB9 output labeled "To Fast ADC", pins 1 and 6 (not the same name but, by process of elimination, we assume that "OFS drive monitor" is, in the drawing, "InLoopOut±") , so we can rule out the Pcal chassis. Due to lack of time, however, we were not able to pinpoint the step at which this signal is lost.
Tony found the next step in our hunt: Page 3 of D1300226V13 shows the ADC side of "To Fast ADC", specifically, "ADC CHAN±00" is assigned, in the drawing, to InLoopOut± . I am tagging CDS for any insight on their side. Discussions and a follow-up plan are in progress to find the signal.