12th may2004 fulvio ricci i o ilias-strega meeting i o ilias - strega meeting fulvio ricci...

12th May2004 Fulvio Ricci Io ILIAS-STREGA meeting

Io ILIAS - STREGA MEETING

Fulvio Ricci

Dipartimento di Fisica, Università di Roma La Sapienza

&

I.N.F.N. Sezione di Roma


The VIRGO-CRYO tasksThe final goalfinal goal of VIRGO-cryo is the construction of full scale prototype of a suspended test mass at cryogenic temperatures

The final goal is reached by merging the activity of task C1 and C3 during the last (4th) year of the project

Task C1 : main activity ==>>the cryogenic payload ( lower part) -->> “Roma La SAPIENZA”

Task C3 :main activity ==>>the cryogenic super-attenuator (upper part) -->> “INFN PISA”

There are several items in common between C1 and C3 also during the first part of the project : for example the development of sensor and actuators at low

temperature, the simulation software …..


VIRGO Cryogen ics Netw orkAcernese F., INFN & University Federico II, NapoliBabusci D., LNF INFN, FrascatiBarone F., INFN Napoli & University of SalernoBarsuglia M., LAL-Orsay IN2P3/CNRSBizouard M.A., LAL-Orsay IN2P3/CNRSBrisson V., LAL-Orsay IN2P3/CNRSBraccini S., INFN PisaBradaschia C., INFN Pisa Brocco L., INFN & University La Sapienza, Roma Calloni E., INFN & University Federico II, NapoliCattuto C., INFN PerugiaCavalier F., LAL-Orsay IN2P3/CNRSCella G, INFN & University of PisaCuoco E., INFN Firenze/UrbinoDattilo V., INFN PisaDavier M., LAL-Orsay IN2P3/CNRSDeWaard A., Leiden University, Leiden, The NetherlandsDe Rosa R., INFN & University Federico II, NapoliDi Fiore L., INFN NapoliDi Virgilio A., INFN PisaDominici P., INFN Firenze/UrbinoEleuteri A., INFN & University Federico II, NapoliFerrante I., INFN PisaFidecaro F., INFN Pisa Frasca S., INFN & University La Sapienza, Roma Frasconi F., INFN Pisa

Frossati G., Leiden University, Leiden, The NetherlandsGammaitoni L., INFN PerugiaGennai A., INFN PisaGiazotto A., INFN PisaGiordano G., LNF INFN, FrascatiGuidi G., INFN Firenze/Urbino Hello P., LAL-Orsay IN2P3/CNRSLa Penna P., EGOLosurdo G., INFN Firenze/UrbinoMajorana E., INFN PisaMarchesoni F., INFN Perugia Martelli F., INFN Firenze/Urbino Mazzoni M., INFN Firenze/Urbino Milano L., INFN & University Federico II, NapoliPalomba C., INFN Roma Passaquieti R., INFN & University of PisaPassuello D., INFN PisaPerniola B., INFN Firenze/Urbino Punturo M., INFN Perugia Puppo P., INFN Roma Rapagnani P., INFN & University La Sapienza, Roma Ricci F., INFN & University La Sapienza, RomaStanga R., INFN Firenze/Urbino Vetrano F., INFN Firenze/Urbino Vicere' A., INFN Firenze/Urbino Vocca H., INFN Perugia

Contact persons: Fulvio Ricci ([email protected]) Stefano Braccini ([email protected] )

mailto:[email protected]

mailto:[email protected]


R&D on Cryogenics

1) Study of the refrigeration system

- noise

- refrigeration power

2) Suspension compatibility: thermal conduction and acoustic quality factor Q measurements

3) Sensors at low temperatures

- accelerometers and position sensing devices

- actuators

Liquid heliumRefrigeratorshybrid system


ILIAS activity of theGravitational Wave group of the

University of Rome La Sapienza & INFN Roma 1

L. Brocco, S. Frasca, G. Martinelli, M Perciballi, C. Palomba, P. Puppo, P. Rapagnani, F. Ricci, E. Serrani

The main R&D activities to achieve the realization of a full cryogenic suspension (task C1)are focused on

a) Modification of a cryogenic facility hosting a new PTR refrigeration system for the mirror cooling

b) Low temperature monitor of the additional noise generated by the refrigeration system

c) Heat absorption measurements of the mirror substrates

d) Development of sensors and actuators for the position control of the mirror that are compatible with the cryogenic environment

e) Design and construction of a suspension last stage protype for a cryogenic environment


An alternative way to cool down without liquid helium:

the new generation of Cryocoolers

First stage

Second stageBenefit

- Ideal for applications that require efficient operation -No moving parts in cold head. -Minimal vibration, low acoustic noise. - High stiffness cold head allows mounting of heavy loads without extra structural support- High efficiency. 2 to 3 times higher efficiency than GM cryocoolers for loads load temperatures between 55 and 120 K.

A "low frequency” Pulse Tube Refrigerator (PTR) or "G-M style" pulse tube cryocooler, is a variant on a Gifford-McMahon (GM) cryocooler. PTR operate at low frequencies, typically <5 Hz. They use a conventional oil-flooded G-M compressor and a valve set near the cold head to convert the continuous flow of helium from the compressor to a low frequency pressure wave. The cold head itself has no moving parts. Because of their low frequency and high pressure ratio (up to 5:1), these cryocoolers are best suited to low temperature applications, and are competitive with GM cryocoolers at temperatures below about 65 K. Typical efficiencies are in the range of 4 to 9% of Carnot cycle.


Vacuum chamber forhosting the payload

Cold head of Pulse Tube Refrigerator

PTR ready for cooling

PTR Integration in the Rome cryogenic facility


The Rome cryogenic facility: acoustic insulation of the compressor station for PTR


First cooling test with PTR and a mirror sample: the thermal contact resistance


Elastic dissipation study at low

temperature: the case of CaF2


• Scheme– Ring down method

• Excitation– Hammer

• Transducer– PZT on suspension

• CaF2 sample50 x 25 mm

• Multiple loop suspension of NbTi

Experiment setup

Setup side view


Results on a small sample of CaF2


Work to be done

- PT Refrigeration system : noise characterization to be completed in the low frequency region

-In 8 weeks from now, we will start to set up the installation that includes the vibration compensation system-( we hope in the financial support of INFN Commissione II)

- New mirror suspension to reduce the thermal resistance which will be coupled to an elastic holder at 4K

- Q measurements on CaF2 sample of 10 cm in diameter.

-Parallel activity: study of an alternative design based on sub-cooled superfluid helium (at pressure of 1 bar)


Vibration measurements performed on the CRYOMECH refrigerator

with piezo-accelerometers at low temperature


Vertical displacement Horizontal displacementSensor noise

Displacement noise of the cold stage


Vibration free cryostat: modification of the Rome cryogenic facility

Conceptual schemeConceptual scheme


C3 TASK To build an anti-seismic mirror suspension

with mechanical performance similar to VIRGO Superattenuatorsand equipped with items for the extraction of the heat absorbed

by the mirror because of the impinging beam (< 1 W)

C3 task


Al / Cu

~1 m ~ 40 cm

x

Z

Y

30 cm

1 cm

Main Idea: Superattenuator mechanical filters coupled with high thermal

conductivity stripes not affecting mechanical performances

C3 task


1x1x70 cm Aluminum

l=60 cm

Set of stripes

Parallel to Y KY = 2.4 N/mParallel to X KX = 11.4 N/mRotation around Z K

θ

Z = 3.5 /N m Rotation around X K

θ

X = 3.0 /N m

Negligible Stiffness, Negligible effects on Q (measured)Enough thermal conductivity at 4 K (on paper)

C3 task

Preliminary tests of strips has been already performed


COLD FINGER

Very Soft Joint

Cryostat

COLD FINGER

Two possible strategies

C3 task


Possible Improvement (valid for both strategy)

A Superattenuator of reduced size (Prototype assembled for tests at Pisa INFN laboratories)

The new system exhibits less cryogenic incompatible items(no magnets, no glue, no viton,…..) and could be used at 4 K

with minor modifications

C3 task


Conclusions-We need to clarify the contribution of the various institution to the VIRGO cryo tasks

-Specific meetings have to be organized

-The experimental activity is already started at least in two labs

-- Cooling strategy, excess noise and thermal resistance have been identified to be the preliminary topic of this R&D acivitys

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12th may2004 fulvio ricci i o ilias-strega meeting i o ilias - strega meeting fulvio ricci...

Documents

lnf infn

infn university federico

sapienza infn roma

infn pisa brocco

infn pisa frasca

infn pisa giordano

infn pisa dominici

infn pisa marchesoni