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April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Cryogenic payloads and cooling systems (towards a third generation interferometer) part I: An Interferometer.

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Presentation on theme: "April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Cryogenic payloads and cooling systems (towards a third generation interferometer) part I: An Interferometer."— Presentation transcript:

1 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Cryogenic payloads and cooling systems (towards a third generation interferometer) part I: An Interferometer at Cryogenic Temperatures Piero Rapagnani I.N.F.N. Sezione di Roma

2 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Test masses and suspensions thermal noise reduces at low temperature: Thermoelastic noise both of the mirror substrates and coatings decrease: Thermal expansion rate decreases at low temperature; Thermal expansion rate decreases at low temperature; Mechanical Q of some materials increases at low int Thermal lensing: Thermal conductivity increases and consequently reduces thermal gradients on the coating; Thermal conductivity increases and consequently reduces thermal gradients on the coating; Refraction index variation with temperature is very small at low temperature; Refraction index variation with temperature is very small at low temperature; Why cool the mirrors?

3 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS 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 helium Refrigerators Hybrid system

4 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Issues to cool the mirrors Refrigeration system: Refrigeration system: The injected mechanical noise must be negligible, the sensitivity must be preserved:The injected mechanical noise must be negligible, the sensitivity must be preserved: Þ Good mechanical isolation between the mirror and the cooling system; Cooling time of the mirror as low as possible:Cooling time of the mirror as low as possible: Þ Good thermal couplings; Þ High refrigeration power; Suspension system compatible with good mechanical and thermal couplings: Suspension system compatible with good mechanical and thermal couplings: Thermal conductivities change with temperature; Thermal conductivities change with temperature; Mechanical quality factor Q; Mechanical quality factor Q;

5 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Cryogenic fluids and G.W. Detectors The first cryogenic antenna in the world : M=20 kg, T =4 K, ~ 5 kHz No excess noise

6 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS

7 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS The second cryogenic antenna of the Rome group -1978: M~ 400 kg, T =4 K, ~ 1.8 kHz Excess noise in the first phase of operation: Due to suspension system!!

8 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Advantage of the superfluid liquid Helium: the transition Data from the Antenna EXPLORER installed at CERN He phase transition to superfluid

9 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS The current technique to cool down a Resonant Antenna requires Heavy Work and several weeks Detector duty cycle: less than 1 month. VIRGO For an interferometric antenna 6 masses to be cooled. To preserve the duty cycle this heavy work must be done in parallel.....

10 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS In a BIG Laboratory, large Cryogenic Facilities are possible The example of LHC at CERN: Technologies are available, but are VERY expensive and require extensive manpower The Cryogenic Distribution Line (QRL) for the LHC (Large Hadron Collider). Each of the eight ~3.2 km QRL sectors is feeding Helium at different temperatures and pressures to the local cooling loops of the strings of superconducting magnets operating in superfluid helium below 2 K. With an overall length of 25.8 km the QRL has a very critical cost to performance ratio.

11 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS An alternative way to cool down without liquid helium: the new generation of Cryocoolers First stage Second stage Suitable for applications that require efficient operation: No moving parts in cold head. Minimal vibration, low acoustic noise, reliability. High efficiency: 2 to 3 times higher efficiency than GM cryocoolers for loads temperatures between 55 and 120 K. A Pulse Tube Refrigerator (PTR) or "G-M style" pulse tube cryocooler, is a variant of a Gifford- McMahon (GM) cryocooler. PTR operate at low frequencies, typically <5 Hz. Used a conventional oil- flooded G-M compressor and a valve set near the cold head to convert the continuous flow of helium to a low frequency pressure wave.

12 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS A possible solution Passive vibrational isolation system for the heat link Þ Long heat link Þ Part of the refrigerating power absorbed by the isolators Þ Attenuation of the refrigerating power

13 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Our solution Active vibration isolation system for the heat link Þ Shorter heat link Þ Refrigerating power preserved

14 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Integration of VFC, payload and Superattenuator

15 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Q from refrigerator Q from laser beam Mirror Reaction Mass: Thermal Shield at ~ 4K Marionetta Reaction Mass: Thermal Shield at ~ 4K High Efficiency Thermal Links Vacuum Chamber and Cryostat Thermal Shields Silicon Monolithic Wire

16 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Q from refrigerator Q from laser beam Mirror Reaction Mass: Thermal Shield at ~ 4K Marionetta Reaction Mass: Thermal Shield at ~ 4K High Efficiency Thermal Links Vacuum Chamber and Cryostat Thermal Shields Silicon Monolithic Wire Rough Estimates give T mirror ~ 10 K

17 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Q from Superfluid Helium Reservoir Q from laser beam Mirror Reaction Mass: Thermal Shield at ~ 1.5 K Marionetta Reaction Mass: Thermal Shield at ~ 1.5 K High Efficiency Thermal Links Vacuum Chamber and Cryostat Thermal Shields Silicon Monolithic Wire A hybrid system using Superfluid Helium could allow to reach T ~ 1.5 K

18 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Thermal Links: Many Materials and Composites available Thermal behavior at low temperatures must be tested

19 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS The short/medium term future: The Cryogenic Suspension Test Facility Still non investigated Problems: Thermal link (T ~ 4 K) Cryogenic (T~ 50 K) Suspension Elements

20 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS 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 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 Contact persons: Fulvio Ricci ( ) Stefano Braccini ( )

21 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS 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

22 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS The VIRGO-CRYO tasks final goal 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 …..

23 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS COLD FINGER Very Soft Joint Cryostat COLD FINGER Two possible strategies C3 task

24 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Work in progress PT Refrigeration system : noise characterization to be completed in the low frequency region. Set up of the vibration compensation system. The results of the FEM simulation will be used to develop a new mirror cryogenic suspension to reduce the thermal resistance. The PT Refrigeration system will be used to study the thermal properties of the materials candidates for the mirrors of a cryogenic interferometer and also of the e.m. actuators which can be used at low temperatures.

25 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS Future work ( if Commission II agree ) - PT Refrigeration system : noise characterization to be completed in the very low frequency region - In 10 weeks from now, we will start to operate the installation that includes the vibration compensation system -Q measurements on CaF2 sample of 10 cm in diameter. - New mirror suspension coupled to an elastic holder at 4K -We will produce also an alternative design based on sub- cooled superfluid helium (at pressure of 1 bar)

26 April 27th, 2006 Piero Rapagnani – INFN Roma ILIAS 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


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