The status report of the auriga detector
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The status report of the AURIGA detector. Luca Taffarello (INFN Sezione di Padova ). Special tanks to L. Conti and G. Vedovato. Summary of the talk:. New detector set-up First Results, calibration and thermal behaviour BUT evidence of noise peaks

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The status report of the AURIGA detector

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The status report of the AURIGA detector

Luca Taffarello

(INFN Sezione di Padova )

Special tanks to L. Conti and G. Vedovato

Luca Taffarello

Summary of the talk:

  • New detector set-up

  • First Results, calibration and thermal behaviour BUT evidence of noise peaks

  • External excitation to identify the input ports to avoid the noise (mechanical excitation @ low frequencies)

  • Strategy to overcome the disturbances

    • Definition of epoch vetoes in A.D. througt thresold identification

    • New dampers and pneumatic isolation system @ low frequencies

  • Result achieve

    • Good data in nigth and week end (2° Dec 2004-18° May 2005)

    • Very stable and gaussian behaviour (from 19 May 2005)

  • Luca Taffarello

    Expected target AURIGA II run with 1999-2003 upgrades

    new mechanical suspensions:

    attenuation > 360 dB at 1 kHzFEM 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 codeframe data format

    Luca Taffarello

    Setting @ T = 4.5K

    = experimental. data

    = simulation

    Evidence of spurious peaks in the bandwidth

    immediatly is started a diagnostic phase to address

    the spurious features in the noise spectra

    Best quiet period December 2003

    Luca Taffarello

    n=865.68 Hz

    ‚n=914.14 Hz

    First step: Calibration of the 3 sensitives modes

    The thermal behaviour of the modes is estimates by the measurement of the real part of the input impedence to the SQUID a 4.5 K



    ƒn=955.63 Hz

    T= 4.5 K

    E bias=7.5 MV/m

    Not evident lost of charge

    This is thermal

    Luca Taffarello


    • mechanical mode near the switch

    • Electrome-chanical modes

    • Mechanical modes of the charge plates



    VERY IMPORTANT not evident excitation with mechanical and-or electromagnetic actuators

    Luca Taffarello

    Complete control of the internal sources of noise

    (Note: one-sided spectra !)

    December 2004

    after the first


    detector up the


    Luca Taffarello

    Strategy to cope the spurious peaks

    • Identification of noise sources: noise hunting

    • Definition of the possible hardware solutions: 2 steps

      • Rubber dissipation layer below the cryostat(roll-off frequency 8-10 Hz Q=2)

      • Active-air mount (Vibraplane KS) automatic leveling/heigth control low vertical natural frequency and orizontal isolation 1-2 Hz internal damping Q=2 and broad load range)

        Very important parameter the Q factor to avoid other nolinear-coupling where the seismic power is higher and the movement of the cryostat can generate dangerous mechanical stress in the detector

    • Decision to maintain on air the detector because from the analysis data is possible to understand more what is wrong and to control directly the efficiency of the new set-up

    • Definition of epoch vetoes to obtain time period of data workable

    Luca Taffarello

    Noise hunting: 3 step analysis

    • Definition of peaks or band noise sources

    • Identification of noise sensitive peaks out bandwidth

    • Application of epoch vetoes based by crossing thresholds previous defined applied to this out bandwidth peaks

    Luca Taffarello

    SQUID output

    18-22 Hz

    Analysis of auxiliary channels

    Spurious peak in bandwidth

    894 Hz

    Acc. Inside vacuum chamber

    8-22 Hz


    8-22 Hz





    Luca Taffarello

    Evidence of connection between external (seismic) activities and bandwidth

    sensitive bandwidth

    OUTPUT of


    in the cryostat

    0-22 Hz



    Not Possible

    to determine a correlation between the external disturbances and the response in the sensitive bandwidth

    Evidence for

    not-linearity behaviour

    Luca Taffarello

    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

    950 Hz





    900 Hz


    Sunday - Clean Spectrum

    One year of data between dec. 03 to dec 04

    Sp= spurious

    Luca Taffarello


    “Normal” Noisy spectrum

    Luca Taffarello

    Run 590 (Time-Frequency)

    from Sat 11h-13/11/04 to Mon 12h-15/11/04

    Clean Raw Data



    Noisy Raw Data


    Only during the Sunday nigth is possible see the better spectra

    duty cycle Gaussian and stationary very poor 20 %,

    evidence of Monday morning effect, Human Activities?

    Luca Taffarello

    Noisy Raw Data









    Run 590 (Time-Frequency)

    5 hours

    It is possible to define some group of spurious peaks correlated

    F means Family, during the history different family appear and dissapear

    Luca Taffarello

    More clean data, long period good in the nigths and in week-end

    F5 Veto (120 s)

    236.95 +/- 0.2 Hz

    Run 608 - Vetoes

    Wide Band Veto

    F1 Veto (60 s)

    241.25 +/- 0.5 Hz

    F7 Veto (60 s)

    1133.2 +/- 2 Hz

    Wide Band





    4000 s Time-frequency behaviour during normal day

    Luca Taffarello

    F5 Veto 236.95+/- 0.2 Hz

    F5 893.63 Hz

    F5 Veto

    Luca Taffarello


    Ada lck psp plugin @ 236.95+/- 0.2 Hz



    Threshold veto



    Luca Taffarello

    First hardware up-grade: rubber layer of Sylodamp (Angst Pfister)

    Starting new run 2 Dec. 2004

    Previous position

    Position control feed-back

    lift used with the liquid helium

    inside the dewars

    Luca Taffarello

    AURIGA Events [no vetoes]


    Italian Holiday

    Luca Taffarello

    AURIGA Events [with vetoes]


    Is possible to apply the epoch vetoes and the result is a duty cycle 60 %

    Luca Taffarello

    AURIGA Events [with vetoes & prob>0.00001]


    a test of consistency about the shape of the burst

    Luca Taffarello

    AURIGA Events [with vetoes & prob>0.00001]


    Good stability of the detector in absolute amplitude

    Luca Taffarello

    SNR Distribution (with vetoes) (Simulation/Red)

    3 events


    SNR >10


    9 days


    Luca Taffarello

    Last hardware up-grade:external suspensions low frequency and with vibrational damping

    Air springs: effective above1-2 Hz

    Luca Taffarello

    Metal-arc welding with liquid helium inside the dewarswithout bias in the trasducer

    A kind of “wings” to support Auriga above the center of mass of the cryostat

    Luca Taffarello

    Low frequency suspensions installed (May 19th)

    Final configuration

    Ferroconcrete Pillar

    Luca Taffarello

    Low frequency suspensions installed (May 19th)

    suspension activation

    Luca Taffarello

    Before the up-grade

    AFTER! Also during the day

    Luca Taffarello



    Low frequency suspensions installed (May 19th)

    Not so evident and dramatic the isolation effect, but impressive the effect in the data!

    in the best case 1 order of magnitude in amplitude

    Luca Taffarello

    Perfect Gaussian and stationarybehaviour, duty cycle > 98%

    Luca Taffarello

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