1. Noise Projections for GEO 600 Joshua Smith GEO Meeting 11.10.06

2. Detector output decomposed detector output: detector output noise source transfer function

3. Noise channels noise channel detector output: detector output noise source transfer function noise channels:

4. Noise projections noise channel detector output: detector output noise source transfer function noise projections: noise channels: noise budget:

5. Simplified procedure I Causality key Notes: 1.Causality key 2.Simultaneous DFTs allow comparison 3.Other variants exist, eg open-loop which requires CLTF

6. Simplified procedure II Causality key Normal operation

7. Simplified procedure III Causality key Normal operation

8. Latest noise budget for S5

9. Noise projection: alignment FB transfer function  feedback noise projection

10. Noise projection: (de)modulation phase I P QH

11. Noise projection: (de)modulation phase II

12. S5 NP Reconstruction Goal: Noise projections (full budget) at any time. Coming soon: ProjMon 1.Transfer functions: Measure accurately about once per month Track using calibration lines 2. Fourier transforms of N j and H: Signals recorded continuously anyway…

13. Calibration lines

14. Tracking transfer functions At calibration line, projection and H should have same amplitude, phase. Ratio and difference indicate TF accuracy. For 10 day test, about 10% 10 o

15. Vetoes of false gravitational waves Noise channels contain almost no GW info Coincident (within windows) events are not GWs ! See Ajith and Martin’s talks ! Example: injected burst-like waveform

16. Noise subtraction: alignment FB Results of a time-domain subtraction Error at a given freq. vs. filter accuracy H’ H

17. The End

18. Noise removal, eg., frequency noise Most important role of NPs in commissioning: Identify limiting noise sources – team removes them

19. Noise projection: laser frequency noise Noise projections well-suited for very complicated systems  Transfer function calculation would require very sophisticated model

20. Limitations: loop gain Single-path loop Workarounds exist: eg., for high loop gain Simulated results

21. Limitations II Single-path loop Split-path loop Workarounds exist: eg., for high loop gain

22. H’ vs signal recycling FB

23. Detector output I detector output: detector output noise source transfer function

24. Detector output II detector output: detector output noise source transfer function