1. Harald Lückfor the GEO600 Comissioning team 1ILIAS Meeting, Palma, Oct. 2005 Title GEO 600 Commissioning Status Based on a talk of Stefan Hild for the WG1 meeting in Perugia Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) Harald Lück for the GEO600 Comissioning team ILIAS meeting Palma, Oct. 2005

2. Harald Lückfor the GEO600 Comissioning team 2ILIAS Meeting, Palma, Oct. 2005 GEO 600 layout 1.5-2 kW 0.09

3. Harald Lückfor the GEO600 Comissioning team 3ILIAS Meeting, Palma, Oct. 2005 Tuning signal recycling to 300 Hz Better knowledge of IFO parameters:  more accurate parameter predictions from simulations  downtuning to 200 Hz realized Fixed instability of MI auto- alignment by setting up a new telescope for DWS. We will stay at 330 Hz !

4. Harald Lückfor the GEO600 Comissioning team 4ILIAS Meeting, Palma, Oct. 2005 GEO 600 design sensitivity

5. Harald Lückfor the GEO600 Comissioning team 5ILIAS Meeting, Palma, Oct. 2005 RF setup OLD setup New setup: Using a less noisy splitter(0/90°) Using a cable as phaseshifter NEW setup Old setup: Dominated by phase noise in the LO path (phaseshifter and splitter(0/90°) Due to this noise Q was mixed into P quadrature.

6. Harald Lückfor the GEO600 Comissioning team 6ILIAS Meeting, Palma, Oct. 2005 Shot noise Green line is the shot noise level calculated from the DC current of the photodiode. We are within a factor sqrt(2) shot noise limited above 1kHz !

7. Harald Lückfor the GEO600 Comissioning team 7ILIAS Meeting, Palma, Oct. 2005 Next step in RF setup (next week) Proposed by Rana and others GOALS: Using only high quality hardware Guaranteeing high RF levels in all components

8. Harald Lückfor the GEO600 Comissioning team 8ILIAS Meeting, Palma, Oct. 2005 Noise projections 21 st of july

9. Harald Lückfor the GEO600 Comissioning team 9ILIAS Meeting, Palma, Oct. 2005 Noise in the SR-long loop Noise in the detection band is entirely limited by front-end- noise (shot noise from the detector). Limits sensitivity from 100 to 500 Hz PROBLEM Large locking range OLG of 10^6 at 0.1 Hz No feedback noise above100 Hz Requirements 1.Servo has a locking mode and a running mode 2.Lowering UGF to get less gain in detection band 3.Using lowpass filter with very steep roll off above UGF (implemeted digitally using a dSPACE system) Solution

10. Harald Lückfor the GEO600 Comissioning team 10ILIAS Meeting, Palma, Oct. 2005 Analog SR electronics Red = acq amp, green = acq pha Dark blue = run amp, brown = run phase Light blue = run2 amp, pink = run2 pha

11. Harald Lückfor the GEO600 Comissioning team 11ILIAS Meeting, Palma, Oct. 2005 Signal Recycling digital Phase @18 Hz = -147 deg

12. Harald Lückfor the GEO600 Comissioning team 12ILIAS Meeting, Palma, Oct. 2005 SR feedback: analog vs. digital

13. Harald Lückfor the GEO600 Comissioning team 13ILIAS Meeting, Palma, Oct. 2005 Sensitivity improvement July to August High frequency improvements: reduction of RF phase noise Low frequency improvements: reduction of Signal recycling feedback noise

14. Harald Lückfor the GEO600 Comissioning team 14ILIAS Meeting, Palma, Oct. 2005 PR-bench Historically grown layout of PR-bench not optimal ! beam clipping too many transmissive optical components too many polarizing components acoustic coupling Goal: Shorten and simplify the HPD path

15. Harald Lückfor the GEO600 Comissioning team 15ILIAS Meeting, Palma, Oct. 2005 Sensitivity after PR bench work Removed resonance structures between 100 and 200 Hz.

16. Harald Lückfor the GEO600 Comissioning team 16ILIAS Meeting, Palma, Oct. 2005 Noise projections 4 th of August

17. Harald Lückfor the GEO600 Comissioning team 17ILIAS Meeting, Palma, Oct. 2005 Michelson length control < 0.1Hz

18. Harald Lückfor the GEO600 Comissioning team 18ILIAS Meeting, Palma, Oct. 2005 < 10 Hz < 0.1Hz Michelson length control Reaction Pendulum: 3 coil-magnet actuators at intermediate mass, range ~ 100µm

19. Harald Lückfor the GEO600 Comissioning team 19ILIAS Meeting, Palma, Oct. 2005 < 10 Hz > 10 Hz < 0.1Hz Michelson length control Reaction Pendulum: 3 coil-magnet actuators at intermediate mass, range ~ 100µm Electrostatic actuation on test mass bias 630V, range 0-900V= 3.5µm

20. Harald Lückfor the GEO600 Comissioning team 20ILIAS Meeting, Palma, Oct. 2005 Using ESD as actuator Force is proportional to square of applied voltage. high voltages are needed for bipolar actuation a bias voltage needs to be applied Noise is introduced: loop electronics sqrt circuits intrinsic HV amplifier noise

21. Harald Lückfor the GEO600 Comissioning team 21ILIAS Meeting, Palma, Oct. 2005 Sqrt circuits in MI loop ESD: F  U^2 Sqrt circuits are necessary to give full linear force range for acquisition. Drawback: sqrt circuits are noisy 1µV/sqrt(Hz) (=100µV/sqrt(Hz) @ ESD)

22. Harald Lückfor the GEO600 Comissioning team 22ILIAS Meeting, Palma, Oct. 2005 ESD: F  U^2 Sqrt circuits are necessary to give full linear force range for acquisition. Drawback: sqrt circuits are noisy 1µV/sqrt(Hz) (=100µV/sqrt(Hz) @ ESD) Bypassing sqrt circuits after lock is acquired. Sqrt circuits in MI loop

23. Harald Lückfor the GEO600 Comissioning team 23ILIAS Meeting, Palma, Oct. 2005 Noise in MI loop HVA noise = 100nV/sqrt(Hz) (=10µV/sqrt(Hz) @ ESD) HV-amplifier noise can be reduced by decreasing bias voltage or active noise suppression. Suppressing noise introduced by loop electronics needs whitening

24. Harald Lückfor the GEO600 Comissioning team 24ILIAS Meeting, Palma, Oct. 2005 MI loop whitening / dewhitening dewhiten Whiten Whitening right after mixer: zero 3.5 Hz pole 35 Hz Dewhitening for both split passes Passive dewhit- ening done in HV path (0-1kV)

25. Harald Lückfor the GEO600 Comissioning team 25ILIAS Meeting, Palma, Oct. 2005 Sensitivity after fixing noise from MI loop

26. Harald Lückfor the GEO600 Comissioning team 26ILIAS Meeting, Palma, Oct. 2005 Noise Projections 6 th of October: Excess noise @ 200Hz

27. Harald Lückfor the GEO600 Comissioning team 27ILIAS Meeting, Palma, Oct. 2005 Current sensitivity vs. Design sensitivity

28. Harald Lückfor the GEO600 Comissioning team 28ILIAS Meeting, Palma, Oct. 2005 Laser Improvements Exchanged master laser and slave laser pump diodes for new ones (13.3W from Laser) Improved optical path Cleaned components on laser bench → max. 9.2 W @ MC1

29. Harald Lückfor the GEO600 Comissioning team 29ILIAS Meeting, Palma, Oct. 2005 Burst events; Start-of-the-second glitches

30. Harald Lückfor the GEO600 Comissioning team 30ILIAS Meeting, Palma, Oct. 2005 Start-of-the-second glitches: A cal. issue

31. Harald Lückfor the GEO600 Comissioning team 31ILIAS Meeting, Palma, Oct. 2005 New MI longitudinal loop: reduce longitudinal dark fringe deviations Old New Much more gain @ low f Overall gain

32. Harald Lückfor the GEO600 Comissioning team 32ILIAS Meeting, Palma, Oct. 2005 Low Frequency EP Reduction Optional: Digital IM Feedback = analog + res. @ 2.5Hz

33. Harald Lückfor the GEO600 Comissioning team 33ILIAS Meeting, Palma, Oct. 2005 MI AA digital (dSpace) servo 14 th Sept. Digital Analog Added res. gain stages

34. Harald Lückfor the GEO600 Comissioning team 34ILIAS Meeting, Palma, Oct. 2005 MI AA digital (dSpace) servo 8 th Oct. Tilt (Pitch) Rotation (Yaw) Digital filter TFs contain resonant gain stages for suspension resonances

35. Harald Lückfor the GEO600 Comissioning team 35ILIAS Meeting, Palma, Oct. 2005 Reducing Noise in MI AA Loop 19 th Oct. Optimization of gain distribution in MI AA loop reduced FB noise Camera dark noise Before After Feedback noise Before After Rotation (Yaw) Tilt (Pitch)

36. Harald Lückfor the GEO600 Comissioning team 36ILIAS Meeting, Palma, Oct. 2005 Stationarity / Gaussianity Log(N) Histograms of BLRMS

37. Harald Lückfor the GEO600 Comissioning team 37ILIAS Meeting, Palma, Oct. 2005 Current work / next steps Non stationary noise (already partly? cured) Decrease low frequency EP deviations for most loops, i.e. increase gain (partly done) Improve RF set-up Enhance to full input power Join S5. First in overnight/weekend mode –When close to design sensitivity join in 24/7 mode

38. Harald Lückfor the GEO600 Comissioning team 38ILIAS Meeting, Palma, Oct. 2005 Sensitivity improvement of GEO

39. Harald Lückfor the GEO600 Comissioning team 39ILIAS Meeting, Palma, Oct. 2005 ¿Preguntas? Translation Alta Vista Babelfish Sunset in Ruthe