Virgo commissioning status M.Barsuglia LAL Orsay

1. Virgo commissioning statusM.BarsugliaLAL Orsay

2. The central interferometer Spring 2001- Summer 2002 BS Test of the technical choices during end of the construction Acquire experience (no prototype in the Virgo community)

3. Technical choice validation • Suspensions • long term operation, robustness. • direct measurement of the attenuation at 4 Hz • hierarchical control (top stage, reference mass) • Digital controls • local controls, control of SA resonances, lock acquisition, WFS • Output mode-cleaner • locking, contrast improvement • Local controls

4. Suspension system Top stage Last stage Seismic filters

5. Detection system

6. OMC locking Transmitted power TEM00 TEM00 TEM00 TEM00 c2 signal

7. CITF sensitivity during e-runs Alignment control Sept 2001 Frequency noise July 2002

8. Lock robustness during e-runs Run #losses duty cycle longest lock E0 1 98% ~ 51 h E1 1 85%~ 27 h E2 3 98%~ 41 h E3 4 98%~ 40 h E4 4 73% ~ 14 h ITF stored power ~ 200 W

9. July 2002  September 2003: Upgrade to Virgo • mirrors installation • arm completion, vacuum • ITF upgrades (mode-cleaner, local controls, …) • September 2003: Virgo commissioning

10. Commissioning plan • North arm • Lock acquisition • output mode-cleaner • 3-days engineering run • frequency stabilization • WFS • hierarchical control (top stage, marionetta, reference mass) • West arm • Recombined ITF • full ITF

11. Interferometer operation: shifts • 2 8-hours shifts during commissioning Morning Shift (8h-15h) Evening Shift (16h-23h) Task #1 Task #2 1 Interferometer operator 1 Interferometer operator 1 Interferometer coordinator 1 Computer operator 1-3 People working on commissioning task #1 1-3 People working on commissioning task #2 Daily meeting (15h-16h) • 2 tasks in parallel

12. PR BS • 1 pole at 0.01 Hz • 2 zeros at 10 Hz • 2 poles at 800 Hz • 1 pole at 1000 Hz |Gain| frequency Hz North cavity locking scheme • angular control (pitch, yaw) • no longitudinal damping ~ 6 W 50 Hz BW, digital control

13. m Signals and simulation Lock acquisition speed threshold ~ 10 mm/s Linearized error signal No Linearized error signal Correction Transmitted P Time domain Simulation (Siesta)

14. locking • Locking at the first trial • first lock ~ 1 hour • frequency noise Transmitted power Frequency noise reduction

15. Lock acquisition statistics • with the linearized error signal • 24 locking events collected locking and delocking the cavity • 23 lock acquisition at the first attempt, only 1 failed locking attempt

16. Lock acquisition statistics • Relative velocity between the mirrors computed for each locking attempt 2.5mm/s: mean value of the velocity • 8mm/s: maximum velocity for the lock acquisition success • 12.5 mm/s: velocity of the failed event Failed locking attempt v ~ 12.5 8

17. Output mode-cleaner locking c 2 Reflected P Transmitted P 2 min Error signal State Temperature

18. Sensitivity (m/Hz) Before OMC After OMC Output mode-cleaner locking -II 1. Cavity locked with ~ 1% of the light 2. Mode-cleaner locked 3. Control transferred to this phd ~ 99% of the light

19. Control noise ? Frequency noise MC length control noise Electronic noise (ADC) Shot noise North cavity noise budget

20. Ref Cav laser 300 kHz 50 Hz 50 Hz

21. Transmitted P during C1 run 3 days 14-17 november Seismic Noise problem 2 Long locks tests

22. Seismic noise problem • large seismic noise during the run @300 mHz (microseismic peak) • new inertial control scheme “less inertial” • marionetta roll resonance at 300 mHz excited • new local controls: sensing coupling rollyaw • solution found new inertial damping filter, in test.

23. Tidals during C1 run Correction sent to the end test mass 50 mm

24. Commissioning plan • North arm • Lock acquisition • output mode-cleaner • 3-days engineering run • frequency stabilization • WFS • hierarchical control • West arm • Recombined ITF • full ITF

25. Ref Cav laser 300 kHz Frequency stabilization 50 Hz 50 Hz

26. Ref Cav laser 300 kHz Frequency stabilization • 3 actions: • unlock reference cavity • change IMC curved mirror locking point • open second stage of frequency stabilization 50 Hz 50 Hz 10 kHz

27. Ref Cav laser 300 kHz Frequency stabilization Last step: DC control of laser frequency 1 Hz 50 Hz 20 kHz.

28. Frequency stabilization: first tests Cavity trans P Test mass corr Cavity err sig 2nd stage ON 2nd stage ON Cavity corr OFF • switch • oscillations • simulink model

29. WFS control matrix • optical matrix measured • filter ready

30. WSF control

31. WFS control matrix • optical matrix measured • filter ready • will be tested in early january • transition from local controls  WSF control

32. 2nd (west) arm locking Error signal Transmitted power • cavity locked in a stable way yesterday • same algorithm, same filter of north cavity • preliminary analysis of 2 cavities optical properties

33. Commissioning plan • North arm • lock acquisition • output mode-cleaner • 3-days engineering run • frequency stabilization • WFS • hierarchical control (top stage, marionetta, reference mass) • West arm • Recombined ITF • full ITF

34. Hierarchical control: 3 points

35. Force applied to mirror No feedback to top stage 3.5 mN with feedback to top stage Hierarchical control: top stage Slow corrections (f < 70 mHz) Done during the CITF commissioning Fast corrections (f > 70 mHz)

36. Hierarchical control: marionetta • acquire the lock with the reference mass • move the control to the marionettaDAC noise reduction • complicated transfer function  simulations

37. Commissioning plan • North arm • Lock acquisition • output mode-cleaner • 3-days engineering run • frequency stabilization • WFS • hierarchical control • West arm • Recombined ITF (january) • full ITF

38. Recombined ITF B8 • start noise analysis west arm ~ 250 mW north arm B7 B5 B1p B2

39. Lock acquisition B8 Step 1: lock north arm using pick-off 5 Done Step 2: lock west and mich B7 B5 B1p B2

40. Recombined ITF: simulation north cavity locked west cavity locked mic locked Acq_north ON Acq_west_mic ON Trigger west&mic satisfied Trigger north satisfied

41. Commissioning plan • North arm • Locking, output mode-cleaner (done) • 3-days engineering run • frequency stabilization, WFS (in progress) • hierarchical control (top stage, marionetta, reference mass) • West arm (in progress) • Recombined ITF (january) • full ITF

42. Lock acquisition for full ITF • Lock acquisition LIGO method • Time-Domain simulation (Siesta) • Now transition 34 State 2 locked State 3 locked

43. Summary • North arm • Lock acquisition (done) • output mode-cleaner (done) • 3-days engineering run (done) • frequency stabilization (in progress) • WFS (in progress) • hierarchical control (january) • West arm (done) • Recombined ITF (starts december 29th) • full ITF (?) • Science (?)