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Status of the commissioning of the AURIGA detector

Status of the commissioning of the AURIGA detector. Luca Taffarello (INFN Sezione di Padova) on behalf of AURIGA Collaboration. Summary of the talk:. New detector set-up First Results, calibration and thermal behaviour Investigation of the un-modelled noise peaks

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Status of the commissioning of the AURIGA detector

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  1. Status of the commissioning ofthe AURIGA detector Luca Taffarello (INFN Sezione di Padova) on behalf of AURIGA Collaboration Luca Taffarello

  2. Summary of the talk: • New detector set-up • First Results, calibration and thermal behaviour • Investigation of the un-modelled noise peaks • Up-conversion of low frequency vibrations • Solution of the problem • New mechanical isolation at low frequency • Result achieved: very stable and gaussian behaviour • Duty Cycle 98 % (from 19th May 2005) Luca Taffarello

  3. Expected target AURIGA II run with 1999-2003 upgrades new mechanical suspensions: attenuation > 360 dB at 1 kHz FEM modelled new capacitive transducer: two-modes (1 mechanical+1 electrical) optimized mass new amplifier: double stage SQUID 200 henergy resolution new data analysis: C++ object oriented code frame data format Luca Taffarello

  4. II RUN @ T = 4.5K = data = simulation Noise hunting in cryogenic operation Best initial result of II run • Spurious peaks in the sensitive band • High false alarm rate Luca Taffarello

  5. Raw Data F5 F5 F5 F5 F1 F1 F1 F1 Non Stationary Performances Sensitive frequency band Time (5 hours) It is possible to classify spurious peaks in correlated “Families” (F1..F5..) in time families appear and dissapear Luca Taffarello

  6. Calibration: The dissipations of the 3 sensitives modes Measurement of the real part of the impedence seen by the SQUID ‚ n=865.68 Hz  ƒ QLV=1.15 106 QHV=1.15 106 ‚n=914.14 Hz QLV=5 106 QHV=0.74 106 ƒn=955.63 Hz QLV=0.45 106 QHV=0.75 106 HV E bias=7.5 MV/m Q in operation ~ 400-1000 cold-damping No evidence of discharge Luca Taffarello

  7. Calibration: the mechanical transfer function of the antenna A mechanical modes in the transducer charge line B Electromechanical modes C Mechanical modes of the charge plates A C B VERY IMPORTANT not evident excitation with mechanical and-or electromagnetic actuators Luca Taffarello

  8. Low Frequency Motions are Up-Converted! Accelerometer Inside vacuum chamber 8-22 Hz 894 Hz Spurious peak in the sensitive band SQUID output 18-22 Hz Seismometer 8-22 Hz 4 days friday-monday Luca Taffarello

  9. Evidence of the connection between the external (seismic) activity and the spurious peaks excitation in the sensitive band sensitive bandwidth OUTPUT of SEISMOMETER on top of the cryostat 0-22 Hz 1 DAY to determine a correlation between the external disturbances and the response in the sensitive bandwidth Evidence for nolinear behaviour Luca Taffarello

  10. Run 590 (Time-Frequency) from Sat 11h-13/11/04 to Mon 12h-15/11/04 Clean Raw Data Sat Sun Noisy Raw Data Mon Only during the Sunday nigth it is possible to get clean spectra The duty cycle “gaussian and stationary” very poor 20 %, evidence of effects of Human Activity Luca Taffarello

  11. Low frequency mechanical excitation and response in the detector bandwidth 2 example also without electrical field Shaking frequency 16.57 Hz Effect: some cluster with more peaks equidistant 16.57/3 Hz Shaking frequency 18.62 Hz Effect: all the multiple Not possible to reach shaking frequency below 10 Hz the seismic noise is too power Luca Taffarello

  12. Strategy: new mechanical isolation at low frequency Step 1: Dissipation stacks material: Polyurethane (Sylodamp by Angst Pfister), high dissipation Q=2 roll-off frequency 8-10 Hz Step 2: Active-air mounts (Vibraplane by Kinetic Systems) internal damping Q=2 lower natural frequencies 1-2 Hz, automatic leveling/height control • Hardware up-grades integrated during cryogenic operations Luca Taffarello

  13. STEP 1: rubber stacks between floor and cryostat supports 2 Dec. 2004 Position control feed-back lift used with the liquid helium inside the dewars Luca Taffarello

  14. First breakthrough: achieved design sensitivity (Dec 2004) 60% DUTY CYCLE !!! Go ahead !! Luca Taffarello

  15. F5 Veto 236.95+/- 0.2 Hz F5 893.63 Hz F5 Veto Luca Taffarello

  16. F5 Noise Amplitude @ 236.95+/- 0.2 Hz amplitude F5 Threshold veto F5 Veto Luca Taffarello

  17. AURIGA Events [no vetoes] SNR Italian Holiday Luca Taffarello

  18. AURIGA Events AFTER vetoes SNR Is possible to apply the epoch vetoes and the result is a duty cycle 60 % Luca Taffarello

  19. SNR Distribution AFTER vetoes(Simulation=Red) 3 events with SNR >10 during 9 days SNR Luca Taffarello

  20. Second Step: seismic isolation up-gradeexternal suspensions low frequency with vibrational damping Air springs: effective above 1-2 Hz Luca Taffarello

  21. Metal-arc welding on cryostat while keeping liquid helium in “wings” to support Auriga above the center of mass of the cryostat Luca Taffarello

  22. Step 2: integration of low frequency suspensions (May 19th) Final configuration Ferroconcrete Pillar Luca Taffarello

  23. Last breakthrough: achieved 98% Duty Cycle (May 2005) “Before the up-grade” “After the up-grade” Luca Taffarello

  24. On line effect (May 19th) Sensitive frequency band suspension activation 1 hour Luca Taffarello

  25. Low frequency motion comparison Luca Taffarello

  26. Current AURIGA Burst Search • Thermal at 4.5 K • 13.6 days, • Epoch vetoes not needed • apart from cryogenic maintenance • Duty time 98% • Very stationary • Gaussian noise • Outliers 9 events/day with SNR > 6 • Event rate 3700 /day with SNR > 4 Absolute amplitude 5.7 10-22 / Hz Luca Taffarello

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