Using DTT with 0.001 Hz BW and 10 averages (.xml template attached), chi_XY (see LIGO-P2000113 for details) was calculated by hand during several quiet lock stretches of at least 2 hours during the past few days.
| Date | Start Time | chi_XY |
|---|---|---|
| 5/20/2023 | 08:00 | 1.00056 |
| 5/20/2023 | 09:00 | 1.00079 |
| 5/22/2023 | 11:10 | 1.00057 |
| 5/23/2023 | 21:00 | 1.00012 |
Our calculation of chi_XY in the front-end code needs some tuning of the demodulation and filtering parameters as can be seen in the attached plot. This will get some attention soon; it is the focus of a planned summer SURF student investigation here at LHO.
chi_XY compares the calibrations of the fiducial Pcal displacements induced at both end stations. Corrections factors have been applied at each end station (H1:CAL-PCALX_XY_COMPARE_CORR_FACT = 0.9988 and H1:CAL-PCALY_XY_COMPARE_CORR_FACT = 1.0015) such that chi_XY should be close to unity. It appears that both Pcal systems are stable, operating as expected.
