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April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Cryogenic payloads and cooling systems Cryogenic payloads and cooling systems (towards a third generation interferometer)(towards a third generation interferometer)
part II:part II: the Vibration Free the Vibration Free Cryostat and the Cryogenic Mini-Cryostat and the Cryogenic Mini-PayloadPayload
Paola PuppoPaola PuppoI.N.F.N. Sezione di Roma I.N.F.N. Sezione di Roma
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Refrigeration system study:
The Vibration Free Cryostat (V.F.C.) Thermal behavior; Cryogenic Instrumentation for the monitor and control
displacement sensor (low frequency) cryogenic accelerometers (high frequency)
Results on the vibration control
Cryogenic small scale payload made of silicon:
• Assembly test
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Refrigeration system studyRefrigeration system study::
The cryogenic facility: Vibration Free The cryogenic facility: Vibration Free Cryostat (Cryostat (V.F.C.V.F.C.))
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
The Vibration Free Cryostat: principle schemeThe Vibration Free Cryostat: principle scheme
V.F.C.
Spring
Active vibrational Active vibrational isolation system for isolation system for the heat linkthe heat link
Shorter heat linkShorter heat link Refrigerating power Refrigerating power
preservedpreserved
It is necessary to It is necessary to monitor the vibration monitor the vibration at low temperature at low temperature and to act on the and to act on the refrigerator:refrigerator:
Accelerometers Accelerometers and position and position sensing devices;sensing devices;
Actuators;Actuators;
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Sumitomo cryocoolerSumitomo cryocooler
Cooling capacity1st stage 10W/20W @ 45 K (50/60 Hz)
2nd stage 0.5W/0.5W @ 4.2 K (50/60 Hz)
Lowest temperature < 3 K
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Vibration Free Cryostat:Vibration Free Cryostat:
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
1
2
3
4
The jelly fish thermal contact
The special bellow
The piezo actuator
Vibration Free Cryostat: detailsVibration Free Cryostat: details
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Current statusCurrent status
Thermal behavior of the system (FEM and data);
Mechanical noise characterization completed;
PT Refrigeration system : set up of the vibration compensation system;
Mechanical transfer function measurements;
Control of the pulse tube induced vibrations;
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Thermal FEM simulationThermal FEM simulation
Cold Stage 1
Cold Stage 2
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
ResultsResultsThe results are used to evaluate the thermalpowers extracted at the cold stages points.
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Noise characterization:Noise characterization:
Low Frequency noiseLow Frequency noise
High Frequency noiseHigh Frequency noise
Results:• Two orders of magnitude gained at frequencies grater than 100 Hz
10-10
10-9
10-8
10-7
10-6
10-5
0,0001
0,001
0 5 10 15 20 25
m/ sqrt(Hz) cold head m/ sqrt(Hz) Vacuum Chamber
Hz
10-16
10-14
10-12
10-10
10-8
10-6
0,0001
0 1000 2000 3000 4000 5000 6000 7000
m/ sqrt(Hz) Vacuum Chamberm/ sqrt(Hz) Head
Hz
Setup:•1 Accelerometer placed on the cold head•1 Accelerometer on the top of the vacuum chamber
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Position sensor : the optical fiber Position sensor : the optical fiber bundlebundleMeasurement set-upMeasurement set-up
Material: optran silica for broad temperature rangeProtection: PVC or s.s.Laser source : 638 nm (red)Target: polished surface
Target
Laser
Photodiode
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Vertical Noise Vertical Noise measurementsmeasurements
10-8
10-7
10-6
10-5
0.0001
0 2 4 6 8 10 12
Dftt(m/sqrt(Hz))
Hz
The optical sensor is sensitive in the low frequency range and it is used as the readout ofthe control system.
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Vertical Tranfer Vertical Tranfer function function
MeasurementsMeasurements
Exciting source: piezo actuators
Sensor: optical sensor onthe II stage
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Preliminary results of VFC (no payload in the inner chamber):• Cooling down OK;• Vertical control monitoring the cold head OK (position sensing);• Study of all the mechanical couplings inside the VFC.
INFN-Roma
,
-120
-110
-100
-90
-80
-70
-60
-50
-40
0 1 2 3 4 5
Mag open-loopMag closed-loop (10 Hz bandwidth)
dB
f [Hz]
DAC noise plateau + no-roll-off filter effect
Preliminary results of VFC (no payload in the inner chamber):• Cooling down OK;• Vertical control monitoring the cold head OK (position sensing);• Study of all the mechanical couplings inside the VFC.
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
• Outer tank mode excitedby the control system and visible on the cold head residual motion when the control loop is closed;
• Such a coupling can be removed by modifying the mechanical set up both of the optical readout and of theouter tank;
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Cryogenic reduced scale silicon payloadCryogenic reduced scale silicon payload
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Mini payload made Mini payload made of silicon:of silicon: 1/3.5 1/3.5
scaledscaled
Si
Si
Copper insert in the silicon marionetta suspension point
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
1. Silicon mirror2. Copper reaction mass of the
mirror3. Silicon marionetta with shaped
copper insert to optimizethe thermal contact with
suspensions, and steel arms4. Reaction mass for marionetta
2
2
4
4
3
Cryogenic Payload, scaled to 1/3 a Virgo payload
1
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Assembly test:Assembly test:thermal links on aluminum thermal links on aluminum
samples of marionetta and mirrorsamples of marionetta and mirror
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
1. Mirror assembly2. Marionetta assembly in its reaction mass3. Connection of the thermal links
1
2
3
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
4.Mirror reaction mass assembly
5.Coils assembly4
5
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
6.The minipayload ready to be suspended on the vacuum chamber flange.
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
Mirror
ReactionMass
Marionettaarms
Marionetta
Reaction Mass for Marionetta Ansys simulationAnsys simulation
April 27th, 2006April 27th, 2006Paola Puppo – INFN RomaPaola Puppo – INFN Roma
ILIASILIAS
ConclusionsConclusions• Cancellation of the extra-noise vibration associated to the cooling system:
•vertical noise measured•transfer function measured•active control performed•thermal study performed
• Minipayload: first assembly test of the payload with aluminum mirror and marionetta. •Next step: to insert the assembled system in the VFC cryostat to cool it down and study the mechanical behavior.