[A proposal for ILIAS NEXT: Cryogenics versus vibration] [I3-FP7 call] Abstract The reduction of thermal noise in solids is a basic requirement in many kinds of detectors involving position or mechanical energy measurements. If cryogenics is used other favorable conditions are met as high quality factors or higher thermal conductivity such that the use of cryogenics appear a natural choice. The proposed activity is targeted to the leading feature of underground detectors. Vibration-free-cryostat (VFC [1,2,3,4]) activity is being proposed to be pursued pursued as JRA ILIAS in order to: study the integration of VFC and cryogenic sensor development with running cryogenics R&D projects for gravitational wave detectors [5,6,7]; study alternative configurations as vibration self-cancellation using double-pulse- tube systems [8]; adapt vibration-free cryo-cooler experience to other astro-particle physics detectors requiring low temperature and quiet environment [9]; design and develop new sensors dedicated to pulse-tube vibration reduction. 1 – Target

2 Paola Puppo - GWADW– May 14 th 2009 – Ft Lauderdale From S. Hild et all. 2 – Motivation

Vibration compensation Passive solutionActive solution Cold point displacement sensor Logic Unit Force Actuation at room temperature A. D. C. D.A.C. Elastic suspension of the cold head 3 – PT cryostats

4 – VFC

5 Vibration of the cold head reduced After the first upgrade displacement noise density

5 – Proposal Submitter Ettore Majorana 6 - Involved People Researchers Massimo Bassan Franco Frasconi (INFN) Ettore Majorana (INFN) Cristiano Palomba (INFN) Piero Rapagnani Fulvio Ricci 7 – Budget request FP7 ILIAS NEXT *kE 4-year temporary position200 Cryogenics and cryogenic vibration sensors 60 Know-how exchange and travel 20 TOTAL280 Technicians Mauro Ciaccafava Maurizio Perciballi submitted to JRA coordination with EC contribution reduced to 23%, Paris 11/09/2009 (TBC, application screwed within 2 weeks)

8 – References [1] Tomaru T. et al., “Vibration analysis of cryocoolers”, Cryogenics, , [2] S. Caparrelli et al., “Vibration-free cryostat for low-noise applications of a pulse tube cryocooler", Rev. of Sci. Inst , [3] E. Majorana et al., “Vibration Free Cryostat for cooling suspended mirrors”, Journal of Physics Conference Series –379, [4] F. Basti et Al., “Closed loop refrigeration systems and vibration control for a cryogenic gravitational-wave detector”, XIX AIV Congress, Senigallia 19 May, 2009 (in press). [5] P. Rapagnani and P. Puppo, “Cryogenic developments for future GW interferometers”, waves-interferometer-cryogenics-puppo-elba-science-technology-ppt-powerpoint/ GWDAW, Elba, Italy, waves-interferometer-cryogenics-puppo-elba-science-technology-ppt-powerpoint/ [5] K. Kuroda “LCGT Project” [7] K. Agatsuma, “Thermal noise limited underground interferometer CLIO”, Amaldi 8, 25 Giu (in press). [8] Suzuki T. et al., “Pulse tube cryocooler with self-cancellation of cold stage”, Cryo Prague [9] R. Ardito et al. “CUORE Collaboration: A cryogenic underground observatory for rare events”

AUXILIARY NOT USED

Mirror cooling to get ET sensitivity  Test masses and suspensions thermal noise reduces at low temperature:  Thermoelastic noise both of the mirror substrates and coatings decrease:  Thermal expansion rate a decreases at low temperature;  Thermorefractive noise  Losses of some materials decrease at low temperature 9 Paola Puppo - GWADW– May 14 th 2009 – Ft Lauderdale

: Silicon for substrates and suspensions: high thermal conductivity very low thermal expansion (zero below 17K)

The Pulse Tube Cryogenerator Second stage First stage Compressor High pressure lines Lenght up to 20 m High pressure flexible line

LCGT project It is a 3km Fabry-Perot MI with a power recycling scheme and equipped with a broadband RSE. The laser power is 150W Main mirrors made of sapphire are cooled at 20K. A SPI impedes the refrigerator- vibration. It is built underground at Kamioka. Two independent interferometers are installed in one vacuum system. The main target is the coalescence of BNS, which can be detected events per year at confidence level of 95% for mass 1.4Msun and S/N=10. Data Taking Starting in 2012 Cost: 132 M$ (without salaries and maintenace) Thanks to Prof. Kuroda - ILIAS Meetng