Reports until 09:51, Thursday 31 October 2019
H1 CAL (CAL)
richard.savage@LIGO.ORG - posted 09:51, Thursday 31 October 2019 - last comment - 10:34, Friday 01 November 2019(52828)
Updated Pcal force coefficients for Tx and Rx power sensors

DriptaB and RickS

This morning, we updated the Xend and Yend Pcal force coefficients for the Pcal power sensor readback signals.

We have decided not to continue with recording all the parameters that go into these force coefficients via the detailed force coefficient MEDM screens (which end up calculating the static force coefficients 16,000 times per second for the whole run) and instead just write the force coefficient into the records such asH1:CAL-PCALX_FORCE_COEFF_CTS2V_T and set the other record values such that their cumulative effect is just to multiply this coefficient by unity.  We plan to update the MEDM screen and variable names ASAP.

The updated force coefficient files for LHO are in the SVN at:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Results/CALCS_FE/lho_xend_pcal_epics_created-20191030.txt
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Results/CALCS_FE/lho_yend_pcal_epics_created-20191030.txt

and for LLO at:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/L1/Results/CALCS_FE/lho_xend_pcal_epics_created-20191030.txt
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/L1/Results/CALCS_FE/lho_yend_pcal_epics_created-20191030.txt

The calculation of the force coefficients is performed in python code written by Ethan Payne.  The parameters for the calculations and the resulting force coefficients are listed in the tables in the .pdf file in the comment attached below.

The force coefficients have changed from the values entered at the beginnign of the O3a run (on 20190401) by:
Xend Tx: +0.13%
Xend Rx: +0.29%

Yend Tx: +0.17%
Yend Rx: +0.27%

After updating the Pcal suspension filters (in, for instance H1:CAL-PCALX_TX_PD, hopefully later today) we expect the calibrated Pcal displacements to change by:
Xend Tx: +0.11%
Xend Rx: +0.27%

Yend Tx: +0.31%
Yend Rx: +0.42%

The force coefficients have changed mostly due to updated responsivity ratio estimates benefiting from additional measurments during the O3a run and inclusion of non-ideal ADC coversion factors.

The differences between the changes in force coefficients and the changes in the displacement coefficients is from discrepancies between the O2 ETM masses that have been used in the Pcal suspension filters and the O3 masses that should have been and will be implemented.
Note that these changes will not be fully realized until these filter files are updated.

The Epics records have been updated to the following values:

For Xend:
caput H1:CAL-PCALX_FORCE_COEFF_CTS2V_T 7.9278e-13
caput H1:CAL-PCALX_FORCE_COEFF_CTS2V_R 6.2344e-13
caput H1:CAL-PCALX_FORCE_COEFF_COS_THETA 0.5
caput H1:CAL-PCALX_FORCE_COEFF_RHO_G 1
caput H1:CAL-PCALX_FORCE_COEFF_ALPHA_W 1
caput H1:CAL-PCALX_FORCE_COEFF_ALPHA_T 1
caput H1:CAL-PCALX_FORCE_COEFF_ALPHA_R 1
caput H1:CAL-PCALX_FORCE_COEFF_GAIN_AA_R 299792458
caput H1:CAL-PCALX_FORCE_COEFF_GAIN_AA_T 299792458
caput H1:CAL-PCALX_OPT_EFF_TX2TM_INNER 1
caput H1:CAL-PCALX_OPT_EFF_TX2TM_OUTER 1
caput H1:CAL-PCALX_OPT_EFF_TM_INNER 1
caput H1:CAL-PCALX_OPT_EFF_TM_OUTER 1
caput H1:CAL-PCALX_OPT_EFF_TM2RX_INNER 1
caput H1:CAL-PCALX_OPT_EFF_TM2RX_OUTER 1
caput H1:CAL-PCALX_OPT_EFF_TOT_INNER 1
caput H1:CAL-PCALX_OPT_EFF_TOT_OUTER 1

For Yend:
caput H1:CAL-PCALY_FORCE_COEFF_CTS2V_T 9.2203e-13
caput H1:CAL-PCALY_FORCE_COEFF_CTS2V_R 6.2702e-13
caput H1:CAL-PCALY_FORCE_COEFF_COS_THETA 0.5
caput H1:CAL-PCALY_FORCE_COEFF_RHO_G 1
caput H1:CAL-PCALY_FORCE_COEFF_ALPHA_W 1
caput H1:CAL-PCALY_FORCE_COEFF_ALPHA_R 1
caput H1:CAL-PCALY_FORCE_COEFF_ALPHA_T 1
caput H1:CAL-PCALY_FORCE_COEFF_GAIN_AA_R 299792458
caput H1:CAL-PCALY_FORCE_COEFF_GAIN_AA_T 299792458
caput H1:CAL-PCALY_OPT_EFF_TX2TM_INNER 1
caput H1:CAL-PCALY_OPT_EFF_TX2TM_OUTER 1
caput H1:CAL-PCALY_OPT_EFF_TM_INNER 1
caput H1:CAL-PCALY_OPT_EFF_TM_OUTER 1
caput H1:CAL-PCALY_OPT_EFF_TM2RX_INNER 1
caput H1:CAL-PCALY_OPT_EFF_TM2RX_OUTER 1
caput H1:CAL-PCALY_OPT_EFF_TOT_INNER 1
caput H1:CAL-PCALY_OPT_EFF_TOT_OUTER 1

 

 

Comments related to this report
richard.savage@LIGO.ORG - 10:34, Friday 01 November 2019 (52849)CAL
Link

Tables of previous and updated force and displacement coefficients and O2 and O3 masses are in the attached .pdf file.

Non-image files attached to this comment
jeffrey.kissel@LIGO.ORG - 12:36, Thursday 31 October 2019 (52834)
Link 

Talking with Rick further, the interpretation of the "change in calibrated displacement," which here I'll call xi is as follows:

           [   NOW               ]
     xi =  [ --------    -    1  ]  * 100
           [ EARLIER             ]

where NOW is after today when the coefficients were installed (updated to be closer to the correct truth), and EARLIER is prior to today, during all of O3A (which therefore had a level systematic error proportional to xi).

I'll write a separate aLOG that combines this aLOG, the material in LHO aLOG 34153, and in T1900169 so that we understand exactly how this correction should be interpreted / displayed in terms of modifying previous reports of IFO response function uncertainty / systematic error, and what it means for h(t), and what it means for the BNS range.