S. Braccini: VIRGO-CRYO activities (10

Io ILIAS - STREGA MEETING
Fulvio Ricci
Dipartimento di Fisica, Università di Roma La Sapienza
&
I.N.F.N. Sezione di Roma
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
The VIRGO-CRYO tasks
The final 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
12th May2004
Io
…..
Fulvio Ricci
ILIAS-STREGA meeting
VIRGO C r yogen
i c s Ne tw o r k
Frossati G., Leiden University, Leiden, The Netherlands
Gammaitoni L., INFN Perugia
Gennai A., INFN Pisa
Giazotto A., INFN Pisa
Giordano G., LNF INFN, Frascati
Guidi G., INFN Firenze/Urbino
Hello P., LAL-Orsay IN2P3/CNRS
La Penna P., EGO
Losurdo G., INFN Firenze/Urbino
Majorana E., INFN Pisa
Marchesoni F., INFN Perugia
Martelli F., INFN Firenze/Urbino
Mazzoni M., INFN Firenze/Urbino
Milano L., INFN & University Federico II, Napoli
Palomba C., INFN Roma
Passaquieti R., INFN & University of Pisa
Passuello D., INFN Pisa
Perniola 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, Roma
Stanga R., INFN Firenze/Urbino
Vetrano F., INFN Firenze/Urbino
Vicere' A., INFN Firenze/Urbino
Vocca H., INFN Perugia
Acernese F., INFN & University Federico II, Napoli
Babusci D., LNF INFN, Frascati
Barone F., INFN Napoli & University of Salerno
Barsuglia M., LAL-Orsay IN2P3/CNRS
Bizouard M.A., LAL-Orsay IN2P3/CNRS
Brisson V., LAL-Orsay IN2P3/CNRS
Braccini S., INFN Pisa
Bradaschia C., INFN Pisa
Brocco L., INFN & University La Sapienza, Roma
Calloni E., INFN & University Federico II, Napoli
Cattuto C., INFN Perugia
Cavalier F., LAL-Orsay IN2P3/CNRS
Cella G, INFN & University of Pisa
Cuoco E., INFN Firenze/Urbino
Dattilo V., INFN Pisa
Davier M., LAL-Orsay IN2P3/CNRS
DeWaard A., Leiden University, Leiden, The Netherlands
De Rosa R., INFN & University Federico II, Napoli
Di Fiore L., INFN Napoli
Di Virgilio A., INFN Pisa
Dominici P., INFN Firenze/Urbino
Eleuteri A., INFN & University Federico II, Napoli
Ferrante I., INFN Pisa
Fidecaro F., INFN Pisa
Frasca S., INFN & University La Sapienza, Roma
Frasconi F., INFN Pisa
Contact persons: Fulvio Ricci ([email protected]) Stefano Braccini ([email protected] )
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
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
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Liquid helium
Refrigerators
hybrid system
ILIAS activity of the
Gravitational 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
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
An alternative way to cool down without liquid helium:
the new generation of Cryocoolers
First stage
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.
12th May2004
Second stage
Benefit
- 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.
Io
Fulvio Ricci
ILIAS-STREGA meeting
PTR Integration in the Rome cryogenic facility
PTR
ready for
cooling
Cold head of
Pulse Tube
Refrigerator
Vacuum chamber for
12th May2004
hosting
the payload
Io
Fulvio Ricci
ILIAS-STREGA meeting
The Rome cryogenic facility: acoustic insulation of the
compressor station for PTR
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
First cooling test with PTR and a mirror sample: the
thermal contact resistance
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Elastic dissipation study at low
temperature: the case of CaF2
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Experiment setup
• Scheme
– Ring down method
• Excitation
– Hammer
• Transducer
– PZT on suspension
• CaF2 sample
50 x 25 mm
• Multiple loop
suspension of NbTi
Setup side view
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Results on a small sample of CaF2
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
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)
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Vibration measurements performed on the CRYOMECH refrigerator
with piezo-accelerometers at low temperature
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Displacement noise of the cold stage
Vertical displacement
12th May2004
Io
Sensor noise
Fulvio Ricci
ILIAS-STREGA meeting
Horizontal displacement
Vibration free cryostat: modification of the
Rome cryogenic facility
Conceptual scheme
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
C3 TASK
To build an anti-seismic mirror suspension
with mechanical performance similar to VIRGO Superattenuators
and equipped with items for the extraction of the heat absorbed
by the mirror because of the impinging beam (< 1 W)
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
C3 task
Main Idea: Superattenuator mechanical filters coupled
with high thermal
conductivity stripes not affecting mechanical performances
Al / Cu
~ 40 cm
~1 m
Z
30 cm
1 cm
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
Y
x
C3 task
l=60 cm
Preliminary tests of strips
has been already performed
1x1x70 cm Aluminum
Set of stripes
Parallel to Y
KY = 2.4 N/m
Parallel to X
KX = 11.4 N/m
Rotation around Z
KZ = 3.5 N/m
Rotation around X
KX = 3.0 N/m
Negligible Stiffness, Negligible effects on Q (measured)
Enough thermal conductivity at 4 K (on paper)
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
C3 task
Two possible strategies
COLD FINGER
COLD FINGER
Cryostat
Very
Soft
Joint
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
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
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting
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
12th May2004
Io
Fulvio Ricci
ILIAS-STREGA meeting