1. Present Superatttenuator performance vs. AdV & ET Requirements S.Braccini for Virgo Suspension group

2. Passive Attenuation

4. Ground Mirror Resonances f -2N Long Pendula 2 Hz Transmission Soft Springs Frequency (Hz)

5. Blade Springs Magnetic Antisprings 8 m

6. Ground Seismic Noise Mirror Seismic Noise Rumore Termico

7. SA design e freccette Filter Chain TF measurements (without Pre-Isolator !)

8. SA design e freccette @ 4.1 Hz < 6  10e-8 CITF Measurements around 2, 4, 9 Hz

9. SA design e freccette CITF Measurements around 2, 4, 9 Hz @ 2.25 Hz 5  10e-6

10. Thermal Noise Measured Upper Limit

12.  L(f) = h(f) / 3000

13. TF max =  L(f) /(LSD Ground Seismic Noise) LSD Ground Seismic Noise = 5 x 10 -7 / f 2

14. Same Exercise for ET sensitivity

15.  L(f) = h(f) / 10000

16. TF max =  L(f) /(LSD Under-Ground Seismic Noise) LSD Ground Seismic Noise (Kamioka) - 5 x 10 -9 / f 2 (Duzel Mine much better)

17. Same Exercise for ET-Xylophone sensitivity

18.  L(f) = h(f) / 10000

19. TF max =  L(f) /(LSD Ground Seismic Noise) LSD Ground Seismic Noise (Kamioka) - 5 x 10 -9 / f 2

20. Valid both for horizontal and vertical seismic noise

21. High Sens Range Larger stability allows longer measurements

22. SA design e freccette frequency ( Hz ) Displacement ( m. Hz -1/2 ) Top Mirror Transfer Function < 10 -10

23. Stressed Measurement T = 41943 s High Sens Range TOP MIRROR 2 x 10 -18 m Hz -1/2 1.2 x 10 -6 m Hz -1/2 TF < 1.7 x 10 -12

24. !! TF = 1.26 x 10 -11

25. ET-Xylophone AdV 1.26 x 10 -11 + Pre-Isolator

26. SA design e freccette X-excitation SA design e freccette Possible Bypass

27. Bypass Indication ? X - Excitation Results

28. HORIZONTAL Integration TimeKind of MeasurementFrequency Disp Top (Lines LSD)Disp Mirror Upper Limit (LSD)TF (s)(Hz)(m Hz^-1/2) 10485Central interferometer2,304,80E-052,50E-105,21E-06 10485Central interferometer4,103,30E-052,00E-126,06E-08 About 20000 sWest Input Cavity Mirror4,304,31E-063,6E-148,36E-09 About 20000 sWest Input Cavity Mirror6,306,02E-065,4E-148,97E-09 10485Central interferometer9,805,70E-064,10E-137,19E-08 About 20000 sWest Input Cavity Mirror10,303,00E-061,8E-166,00E-11 About 20000 sWest Input Cavity Mirror18,302,85E-064,8E-171,68E-11 41943North Input Cavity Mirror29,302,95E-061,50E-175,08E-12 41943West Input Cavity Mirror30,309,39E-076,00E-176,39E-11 41943North End Cavity Mirror31,301,42E-061,80E-171,26E-11 41943West End Cavity Mirror32,301,22E-062,4E-181,97E-12 VERTICAL Included H-V Coupling Integration TimeKind of MeasurementFrequency Disp Top (Lines LSD)Disp Mirror Upper Limit (LSD)TF (s)(Hz)(m Hz^-1/2) 2620Central Interferometer2,251,70E-042,60E-101,53E-06 2620Central Interferometer4,103,00E-043,00E-121,00E-08 25165North Input Cavity Mirror29,301,22E-063,00E-182,47E-12 25165West Input Cavity Mirror30,303,88E-063,00E-187,73E-13 25165North End Cavity Mirror31,304,14E-063,00E-187,24E-13 25165West End Cavity Mirror32,304,43E-063,00E-186,77E-13 X-AXIS 8388North Input Cavity Mirror29,301,18E-063,9E-17 3,30E-11 8388West Input Cavity Mirror30,306,08E-071,26E-17 2,07E-11 8388North End Cavity Mirror31,306,3E-073,9E-18 6,19E-12 8388West End Cavity Mirror32,307,53E-072,31E-17 3,07E-11 Red = Line Detected Blue = Line Not Detected Purple = Upper Limit not useful (too large)

29. ET-Xylophone AdV Upper LimitDetected Without Pre-Isolator (Just filter chain !) 53113 IP Guarantees for this ! Already compliant for ET (Remind that we are speaking of “Upper Limits”

30. Vertical TF measurements (Coupling included in the measurement)

31. Vertical Measurements

32. ET-Xylophone AdV Without Filter Zero (Just filter chain !) 60 F0 Guarantees for this UPPER LIMIT (!) compliant for ET Vertical Upper LimitVertical Detected

33. Preisolator makes safety margin wide in AdV

34. SA are compliant also for ET starting from 4 Hz.... What happens below?

35. @ 2.25 Hz 5  10e-6 Remarkable Attenuation also at 2.25 Hz HORIZONTAL

36. @ 2.25 Hz 1.5  10e-6 Remarkable Attenuation also at 2.25 Hz VERTICAL

37. Yes No Maybe 423 TF f Model Meas. Stage by Stage Measurement (and Model)

38. ET Design Programme Cut-off 3-4 Hz  No Design Study Cut-off 1-2 Hz  Design Study SCIENCE CASE & NEWTONIAN NOISE TO BE DISCUSSED AT ERICE MEETING

39. N 1 Hz 2 Hz ------------------------- {3, 1.6*10-7, 5.4*10-10} {4, 4.8*10-8, 3.3*10-11} {5, 2.6*10-8, 3.4*10-12} {6, 2.3*10-8, 6.7*10-12} {7, 2.1*10-8, 2.6*10-12} Optimized at 1Hz Courtesy G. Cella Horizontal ~50 m G.Cella

40. Simulations + Analytical Computation in progress

41. Actuation Noise

42. Coil Magnet V V -0.2 0.2 V Cavity Length V -0.2 0.2 /100 Locking

44. M Flex Joint g 30 mHz Inverted Pendulum

45. ADC DSPDAC Actuators Accelerometers

46. Superattenuatore Sensors Coil Drivers Motors Sensors Coil Drivers Position & Dampin g DSP: - 96 bit - 60 MFLOPs DAC: - 8 Chan. - 20 bit - 500 KHz ADC: - 8 Chan. -16 bit SAR - 200 KHz Acc. Sens: - 10 -9 m/s 2 - 0 – 100Hz - f.s. 1g Control Electronics System

47. Hierarchical Control

48. ADC DSPDAC Actuators Accelerometers RESIDUAL SWING < 0.1  m

49. WIND SEA MIRROR ACTUATION

50. Tilt

51. Direct Measurement on the ITF !! A.Gennai (VIR 029-A09)

52. Distribution and (its integral) of the maximum of the absolute values of marionetta correction voltage computed on 200 s-long interval (all VSR1 run, itf in science mode)

53. Calm Any

54. Calm Any

55. Setting the marionetta actuation range to 2.2 V we “risk” 1% of duty cycle Calm Any Actuation Noise Reduction by a factor 4 immediately available !

56. Reduction factor 3-4 Wind (5%) 7-8 Calm (95 %) Direct Meas. Now Calm Wind AdV Many other possibility to reduce noise

58. 2009-10 SAFE Resp: F.Frasconi

59. Tilt Control

60. Recent upgrades Gyrolaser: A.Di Virgilio’s group provided an instrument able to monitor ground tilt with the required sensitivity (close to 10 -9 rad/Hz 1/2 ) with high duty cycle. Tiltmeters: The flex-joint solution was killed. A new prototype concevied by A.Giazotto based on a complete different design was assembled (excellent mechanical performance). Piezo Actuation: The entire electro-mechanical system was assembled by F.Frasconi on SAFE bottom ring and monitored by LVDT. Preliminary tests are very encouraging. Vertical to Horizontal Coupling: The MSC group measured the coupling factor exciting marionetta in vertical and looking at the itf with a “surprising result” (TBC).

61. AdV: SA performance are compliant with AdV both for passive isolation and actuation noise ET: Present SA attenuation good also for the ET project (not too demanding above a few Hz) Passive isolation compliant above about 3-4 Hz Design Study necessary if lower frequency will be investigated Actuation Noise is the major concern Conclusions