1. 1 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Calibration Testing Patrick Sutton, with Michael Landry, Gabriela Gonzalez, & Brian O'Reilly

2. 2 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Idea  We have two ~independent means of calibration, which can be compared for consistency.  `Official' calibration: » Measure H, C during dedicated calibration run (hours). Eg. Done Feb 14-15. » Fit measured H data to model, derive H, C, Cb for that time. » Dynamic: Rescale H, C over time using alpha measured from calibration lines; update Cb.

3. 3 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Idea (cont'd)  AutoCalibrator: » Inject swept sine into ETMX/Y and measure transfer function to AS_Q (minutes). » Empirical (no use of model) - independent of `official' calibrations up to treatment of actuation function A(f). » Gives static snapshot of Cb.  Proposal: Use frequent AutoCalibrator sweeps as check on Official calibration. This talk: show examples for S2

4. 4 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Example: H1

5. 5 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Ratio: H1 Official/AutoCal

6. 6 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 More H1 Sweeps

7. 7 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Example: H2

8. 8 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Ratio: H2 Official/AutoCal

9. 9 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 More H2 Sweeps

10. 10 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Lonely L1 Example

11. 11 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Lonely L1 Example

12. 12 LIGO-G030093-00-Z Penn State / LIGO Scientific Collaboration 2003 March 18 Summary: Huh?  See very similar discrepancies between Official and AutoCal calibrations in all three IFOs.  Discrepancy increases with frequency. At 2kHz: » Magnitude: 40% » Phase: 2 radians  Source unknown; will require further investigation.