J. Kissel, D. Tuyenbayev We're still not getting the IFO duty cycle to get the desired uncertainty on the single-frequency actuation strength scale factor measurement of the UIM and PUM stage and we're running out of time, so I've increased the SNR of these temporary lines by another factor of ~3 over yesterday's increase (see LHO aLOG 31108). Oscillator Freq (Hz) Old Amp (ct) New Amp (ct) ETMY UIM 33.7 180 500 ETMY PUM 34.7 81 300 Hopefully Robert's activities tonight won't impact the ~30 Hz region of the sensitivity, and we can turn things off soon.
Jeff K, Darkahn T,
We calculated actuation strengths of L1 (UIM), L2 (PUM) and L3 (TST) actuation stages using calibration lines from 6 lock stretches in the last two days.
Preliminary results are given in the attached plots. Standard deviation on estimations of AU and AP are ~1.2% and for AT is ~0.4%.
Data points were taken at GPS times with HOFT_OK_BIT = 1 (segments are listed below).
# seg start stop duration
0 1162123790.0 1162124750.0 960.000
1 1162124840.0 1162125190.0 350.000
2 1162125280.0 1162125480.0 200.000
3 1162127120.0 1162129210.0 2090.000
4 1162134280.0 1162137150.0 2870.000
5 1162162170.0 1162163370.0 1200.000
Increased line amplitudes will hopefully allow us to get AU and AP actuation strengths with subpercent 1-sigma error bounds.
Jeff K, Greg M, Darkhan T,
After the L1 and L2 line amplitude increase it seems that we got better uncertainties in the esitamtions of the sus. stage actuation strengths.
This time we filtered the data using the IFO range channel, we used 50 MPC as a threshold. And from the remaining data we made historams of three different time intervals. We did not yet investiage why the noise levels of the lines are different at each of these intervals. The uncertainties for A{U,P,T} are given for the least noisy interval (blue data points).
Jeff K, Greg M, Darkhan T,
We calculated [N/ct] actuation force factors calculated from the ~35 Hz independent L1, L2 and L3 lines:
KU = 8.012-8 +/- 3.873-10 N/ct ( std(KU) / |KU| = 0.0048 )
KP = 6.482-10 +/- 2.748-12 N/ct ( std(KP) / |KP| = 0.0042 )
KT = 4.253-12 +/- 1.679-14 N/ct ( std(KT) / |KT| = 0.0039 )
During a Nov. 4 lock stretch we got a factor of 3 improvement of the standard deviations compared to the previous day (blue data points vs. green).
In most recent 2 days we got more data with longer lock stretches, which can help us to better bound the uncertainties. Analysis of this data would require including an updated DARM digital filters, the IFO response changed on Nov. 5 (see LHO alog 31201) which can bias on our calculations if not taken into account.
The outliers were removed in a following way:
- Took >= 50 MPC data and removed data points that fall outside of 2-sigma std. deviation (some large outliers were not filtered by this step);
- one more time calculated std. and mean in the remaining data points and removed 2-sigma outliers (this step helped to remove large outliers).
- The mean and 2std. of these data points were shown with black solid line and dashed lines.
The final reported mean values and standard deviations were taken from the blue data points ( GPS [1162252470, 1162271230] ), L1 and L2 data was least noisy during this period. This mean value and its std. were shown with blue solid and dashed lines.
