April 19, 2023
THE MONOLITHIC SUSPENSION STATUS FOR THE VIRGO
INTERFEROMETER
THE MONOLITHIC SUSPENSION STATUS FOR THE VIRGO
INTERFEROMETER
Helios VoccaUniversity of Perugia
on behalf of the Virgo collaboration
MG12 Paris - July 12 - 18, 2009 2April 19, 2023
NEW VIRGO+ SENSITIVITY
NEW VIRGO+ SENSITIVITY
New thermal noise evaluation by Piergiovanni, Punturo and Puppo includes the viscous contribution of the marionette
Sensitivity curve of Virgo+ including monolithic suspensions:
F. Piergiovanni, M.Punturo, P.Puppo, The thermal noise of the Virgo+ and Virgo Advanced Last Stage Suspension (The PPP effect), Virgo Note: VIR-015C-09.
Qmario=300Qmario=1000No viscousSimple pendulum
10 Hz
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MONOLITHIC SUSPENSIONS MONOLITHIC SUSPENSIONS
Activity tasks Involved Virgo groups:Firenze/UrbinoPerugiaRomaEGO
General Strategy for Monolithic Suspensions Planning:
Payload parts assembled in the new 1500West Clean Room
Mirrors prepared at LMA (Lyon)
IF Possible (by cleanliness tests): payloads assembled in 1500W Clean RoomMG12 Paris - July 12 - 18, 2009
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THE MONOLITHIC ASSEMBLY
THE MONOLITHIC ASSEMBLY
Steel box to host the upper silica clamp on the marionetta
Silica Clampson the marionette
Silica anchorsCoupling to the mirror flats through lateral supports
Silicate bonding
MG12 Paris - July 12 - 18, 2009
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FIBRES PRODUCTIONFIBRES PRODUCTION
Laser pulling of 1.5 mm thick silica bars:WeldingAnnealingControlled pulling
100 W CO2 laser
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100 W CO2 laser pulling facility developed in collaboration with Glasgow group
Produced fibres are:Very reproducible in diameter and lengthReady to be characterized and assembled
FIBRES PRODUCTIONFIBRES PRODUCTION
MG12 Paris - July 12 - 18, 2009
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FIBRES CHARACTERIZATIONFIBRES CHARACTERIZATION
Inspection of the diameter regularity and check of neck reproducibility
Profiles of the necks are equalwithin a 10 μm accuracy level
MG12 Paris - July 12 - 18, 2009
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Measurement of bending lenghts and violin/bouncing frequenciesStatistics on breaking strength
Bending lengths fix the low frequency dynamics of the suspension.
4 GPa
5 kg
Violin mode
Bouncing
Mode (Hz)
Distance between bend.
Points (mm)
453±1 6.0±0.1 669.5±0.2
453±1 6.0±0.1 669.8±0.2
452±1 6.0±0.1 670.2±0.2
451±1 6.0±0.1 669.6±0.2
450±1 6.0±0.1 669.6±0.2
FIBRES CHARACTERIZATIONFIBRES CHARACTERIZATION
MG12 Paris - July 12 - 18, 2009
MG12 Paris - July 12 - 18, 2009 9April 19, 2023
PAYLOAD SUSPENSION AND LOCAL CONTROLPAYLOAD SUSPENSION AND LOCAL CONTROL
marionette and coils
mirror and magnets
reaction mass
Steel AlSl304 Marionetta prototype with PVC arms Dummy reaction mass, coils with peek supports A mirror is inserted in the holder and the system is balanced All the pieces are secured by safety structures Fibre bending points placed on the marionetta and mirror CoM
Transportation test (Fi, Pg, Rm with EGO support) on the dummy payload
Mechanical vibration monitored with accelerometersThe test was successful (no broken fibers! untill January 2009: see
next slide);
m/s2
July ‘08 - Shocks, Dust and Humidity tests July ‘08 - Shocks, Dust and Humidity tests
MG12 Paris - July 12 - 18, 2009 10April 19, 2023
Equivalent weight of the mirror is 70 kg at the moment of breakingCrash test movie on youtube (search monolithic crash)
Jan. ‘09 - Shocks, Dust and Humidity tests Jan. ‘09 - Shocks, Dust and Humidity tests
QuickTime™ e undecompressore Sorenson Video 3
sono necessari per visualizzare quest'immagine.
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DUMMY SUSPENSION IN PERUGIADUMMY SUSPENSION IN PERUGIA
Dummy payload installation in the vacuum chamber actuators
shadowmeter
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LOSS MEASUREMENTSLOSS MEASUREMENTS
Pendulum oscillation decay measurement loss angle = 2.7 10-7
Evidence of excess losses, maybe recoil or support losses Further investigation needed, measurements in progress
Kp/Ks.b.=2.8 10-14
Kp/Kepoxy=5.6 10-
12
waterglass
epoxy glue
silicate bonding
No excess losses are expected from epoxy or silicate bonding
MG12 Paris - July 12 - 18, 2009
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LOSS MESUREMENTSLOSS MESUREMENTS
Tests are going on to identify the source of excess loss:
Measure a 1.5 mm fused silica bar welded to the upper block and clamped in the “monolithic suspension” way.
Friction in the support: direct upper clamp measurement
Recoil losses: measurement with new
suspension
If the losses are due to recoil of the supporting structure, a linear relation between Q and mass should be measured
Different loads (1 kg, 3 kg, 5 kg…) suspended using two marionette-like clamps
MG12 Paris - July 12 - 18, 2009
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New (full) suspension is in preparationNew (full) suspension is in preparationSilicate bonding has been made 2 weeks ago in Lyon clean room.
In august the FS suspension will be mounted.
Measurements on it will go on in Cascina and Perugia
Toward Advanced VirgoToward Advanced Virgo
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Even if a final geometry for AdV mirrors has not been decided yet, an important evolution will be to remove the silicate bonded supports for the monolithic suspension.
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CONCLUSIONSCONCLUSIONS
Fiber production validated and well defined;Monolithic design for fused silica components is ok;Payloads are under construction;Virgo mirror (old north end) with supports, markers and magnets ready to be suspended;
NEXT STEPSComplete FS suspension to be performed in summer in the new 1500W clean room (almost ready);Measurements of the mechanical losses and identification of the excess losses will follow;Final design of the assembly structure to be fixed.
Ready to install at the end of 2009MG12 Paris - July 12 - 18, 2009