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Seismic Isolation for AdV Stefano Braccini – INFN Pisa

Seismic Isolation for AdV Stefano Braccini – INFN Pisa. 2 Hz. Long Pendula. Ground. Resonances. f -2N. Transmisson. Frequency (Hz). Soft Springs. Mirror. Superattenuator. Magnetic Antisprings. 8 m. Blade Springs. Transfer Function Indirect Measurement. Thermal Noise.

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Seismic Isolation for AdV Stefano Braccini – INFN Pisa

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  1. Seismic Isolation for AdVStefano Braccini – INFN Pisa

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

  3. Superattenuator Magnetic Antisprings 8 m Blade Springs

  4. Transfer Function Indirect Measurement Thermal Noise Ground Seismic Noise Mirror Residual Seismic Noise

  5. GEO600 TAMA 300 VIRGO LIGO

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

  7. Residual Seismic Noise Upper Limits Thermal Noise Ground Seismic Noise Mirror Residual Seismic Noise

  8. AdV Sensitivity h(f) frequency (Hz)

  9. Passive Attenuation is not the end of the game….

  10. V V V V 0.2 0.2 Magnet Coil -0.2 -0.2 Lunghezza cavità l/100 Locking

  11. Low Frequency Mirror Swing Ground Mirror

  12. M g Inverted Pendulum Flex Joint 30 mHz

  13. Accelerometers RESIDUAL SWING < 0.1 mm DSP DAC Actuators ADC

  14. Digital Analog

  15. 0-200 mHz top-stage motion affected by wind MIRROR CORRECTION WIND SEA

  16. Tilt

  17. Any Calm Actuator Range Optimization

  18. Adv VIRGO Control noise in windy days (5% of running time)

  19. …… and for third generation? Superattenuator Performance enough for AdV

  20. Studies on Passive Attenuation

  21. High Sens Range Stressed Measurement T = 41943 s High Sens Range

  22. TF < 3 x 10-13 TOP 7.6 x 10-6m Hz-1/2 1.5 x 10-9m Hz-1/2 MIRROR Stressed Measurement T = 41943 s High Sens Range 2 x 10-18m Hz-1/2

  23. Underground input seismic noise will be much smaller WIDE SAFETY MARGIN 1.6 x 10-25Hz-1/2

  24. Shift seismic wall from 3-4 Hz to 1-2 Hz

  25. 2 Hz Long Pendula Ground Resonances f-2N Transmisson Frequency (Hz) Soft Springs Mirror

  26. 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 ~50 m Horizontal

  27. 2 Independent full simulations in progress

  28. Studies on Low Noise Control

  29. Tiltmeters R&D 10-8-10-9 rad Hz-1/2 @ 30 mHz

  30. SAFE

  31. Control Noise (Now) Low Noise DAC development (R&D in progress) 5-10 How much ultra-low freq. dynamics is reduced underground ? Extension of Hierarchical Control………………

  32. CONCLUSIONS Superattenuators are adequate for Advanced Detectors (Passive Isolation & Low Noise Control) A 6D inertial top stage control could help in windy days (SAFE program) ET Superattenuator design dominated by the “seismic wall” frequency requirement (Newtonian noise estimates)

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