L1 S3 Calibration V1.1

March 14, 2004

There was a mistake in the units used for version 1 response function for L1, as noted below. I am posting new V1.1 reference fucntions here, this time with the right units:

This is a calibration for L1, referenced to GPS time 753424982, when a careful measurement of the open loop gain was made by Brian O'Reilly.
The files with the reference functions at this reference time are:

Open Loop Gain (freq[Hz], mag, phase [rad]): (S03V1p1-L1-CAL-OLOOP_GAIN-753424982.txt.gz)

Actuation Function (freq[Hz], mag [strain/DARM_CTRL counts], phase [rad]) (S03V1p1-L1-CAL-ACTUATION-753424982.txt.gz)
Sensing Function (freq[Hz], mag [AS_Q counts/strain], phase [rad]) (S03V1p1-L1-CAL-CAV_GAIN-753424982.txt.gz)
Response Function (freq[Hz], mag [strain/AS_Q counts], phase [rad]) (S03V1p1-L1-CAL-RESPONSE-753424982.txt.gz)

These files were generated with the Matlab program runL1modelV1p1.m; using the model in L1LSCmodel.m and the interferometer parameters in L1IFOparameters_753424982.m.
We used these filter files: L1SUS-ETMX.txt, L1SUS-ETMY.txt and L1SUS-LSC.txt.

L1 S3 Calibration V1.0

Jan 22, 2004

This is a calibration for L1, referenced to GPS time 753424982, when a careful measurement of the open loop gain was made by Brian O'Reilly.
The files with the reference functions at this reference time are:

Open Loop Gain (freq[Hz], mag, phase [rad]): (S03-L1-CAL-OLOOP_GAIN-753424982.zip), plot

Actuation Function (freq[Hz], mag [strain/DARM_CTRL counts], phase [rad]) (S03-L1-CAL-ACTUATION-753424982.zip), plot
Sensing Function (freq[Hz], mag [AS_Q counts/strain], phase [rad]) (S03-L1-CAL-CAV_GAIN-753424982.zip), plot
Response Function (freq[Hz], mag [strain/AS_Q counts], phase [rad]) (S03-L1-CAL-RESPONSE-753424982.zip), plot
Note (March 14,2004): this response function is not in strain/counts, but in meters/count !! See V1.1 calibrations above.

These files were generated with the Matlab program runL1model.m; using the model in L1LSCmodel.m and the interferometer parameters in L1IFOparameters_753424982.m.
We used these filter files: L1SUS-ETMX.txt, L1SUS-ETMY.txt and L1SUS-LSC.txt.

We use the modelled open loop gain to calculate alphas, betas with respect to reference time interval GPS 753424694 - 753425294, using SenseMon's log files for calibration line amplitude and beta parameters.
The file L1_SenseMonitor_CumLog_S3.txt.gz is SenseMon's log file for times between 751486278 (Oct 29, 2003 18:11:05 UTC), and 757831913 (Jan 11, 2004 04:51:40 UTC).
In the reference time interval GPS 753424694 - 753425294, the 927.7 Hz ASQ line amplitude was 0.02101 +/- 0.00010 counts (where the "error" is the standard deviation in the minute estimates calculated by SenseMon in the reference interval).
With respect to this reference time interval, the only possible values of alpha*beta are between 0.40 and 2.27, as indicated in this plot.
We used the Matlab program GenerateL1ABs.m to produce an ascii file L1AlphaBeta.zip with columns [GPS, Alpha*Beta, Alpha,Beta, CalLine/Ref].
[[Note: if you downloaded this file before Jan 22, you got an older version, which had the values up to Dec 17]].

Here is a plot of the alpha*beta parameter vs time (for all times when it had a possible value, not just in science mode);
a plot of alpha*beta, unity gain frequency and phase margin as a function of time in science segments;
and a histogram of alpha*beta, unity gain frequency and phase margin in science segments.
Notice the double hump in the histograms, obvious in the time series, when we fixed the unity gain frquency to be set near 175 Hz rather than 100 Hz.

Gabriela Gonzalez
Last updated: Jan 22 2004, 11:16am.