Reports until 20:23, Wednesday 14 October 2015
H1 CAL (CAL)
richard.savage@LIGO.ORG - posted 20:23, Wednesday 14 October 2015 - last comment - 08:13, Tuesday 20 October 2015(22530)
Comparison of Pcal, CAL_DeltaL_Ext, and GDS_Calib_Strain calibrations at the four Pcal frequencies

Darkhan, Sudarshan, GregM, RickS

The plots in the first attached multi-page .pdf file use SLMtool data (60-sec. long FFTs) taken during the month of Oct. so far.

The first page shows the time-varying calibration factors.

The next eight pages have two plots for each of the four Pcal calibration lines (36.7 Hz, 331.9 Hz, 1083.7 Hz, and 3001.3 Hz).

The first of each set shows the calibrated magnitudes and phases of the strain at each frequency (meters_peak/meter).

The second plot in each set shows ratios (mag and phase) of the three methods (Cal/Pcal, GDS/Pcal, and Cal/GDS).  The center panels (GDS/Pcal) are most relevant because we expect discrepancies arising from the CAL_DeltaL_External calculations not including all the necessary corrections.

The plots in the second multi-page .pdf file show the GDS/Pcal ratios at the four Pcal line frequencies over the time period from Oct. 7 to Oct. 11, with histograms and calculated means and standard errors (estimated as standard deviation of the data divided by the square root of the number of points).

Note that these time-varying factors (kappa_tst and kappa_C) have NOT been applied to the GDS calibrations yet, so we expect the GDS/Pcal comparisons to improve once they are applied.

Non-image files attached to this report
Comments related to this report
shivaraj.kandhasamy@LIGO.ORG - 08:13, Tuesday 20 October 2015 (22669)

The difference of ~9% in 3 kHz line (mean value) probably comes from the foton IIR filtering which is ~10% at 3 kHz i.e., the front-end DARM is 10% higher than the actual value. SInce online GDS (C00) is derived from output of front-end model, it would also show similar difference.  However the offline GDS (C01 or C02) corrects for this and hence expect not to show this difference.