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News in the thermo-mechanical measurement in the Firenze facility. Gianpietro Cagnoli a,b), Enrico Campagna a,c), Elisabetta Cesarini a), Matteo Lorenzini a), Giovanni Losurdo a), Filippo Martelli a,c), Francesco Piergiovanni a,c), Flavio Vetrano a,c). INFN Sez. Firenze
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News in the thermo-mechanical measurement in the Firenze facility Gianpietro Cagnoli a,b),Enrico Campagna a,c), Elisabetta Cesarini a), Matteo Lorenzini a), Giovanni Losurdo a), Filippo Martelli a,c), Francesco Piergiovanni a,c), Flavio Vetrano a,c) INFN Sez. Firenze University of Glasgow University of Urbino 3rd ILIAS-GW Annual General Meeting, London October 26-27, 2006
Scientific activity of Firenze-Urbino group in STREGA • Research lines in STREGA M5 task: “Characterization of the losses of Si fibres at different temperatures, reaching the Liquid Nitrogen temperature” • Measurement of Silicon fibres: first results published in collaboration with the Pisa and Perugia INFN groups RSI 77, 044502 (2006) & CQG 23, 5277 (2006) • Work in progress on thermomechanical characterization of new materials • Facilities setup in Florence lab • Thermal conductance measurement facility • Results on Si and Silicate-bonding • Q measurement facility • Innovative nodal suspension, designed and realized • a measurement facility • Double FP cavity setup being completed
Vacuum chamber Outer tank Liquid N2 30 cm Inner cold shield Outer cold shield Inner tank Liquid He Optical windows Optical windows Experimental chamber Facility for k – The cryostat
INSULATOR BOX HEATER CLAMP THERMOMETERS SAMPLE SAMPLE HEATER COPPER BOX Facility for k Measurements on a Si reed
Facility for kMeasurements on a Si reed Solid lines from Y.S. Touloukian, E.H. Buyco, “Thermo-physical properties of matter”, Plenum, NY, 1970
Facility for k - Si-bonded samples Cold plate • 1”øx ¼ ” silicon disks silicate bonded by the Glasgow group • Work done incollaboration between Glasgow and Florence Heatsink Heater Sample Thanks to G. Frossati for providing the PT1000 sensors
Facility for k- Si-bonded samples • Setup had been optimized for fibers and rods • Heat flux inhomogeneity problems • 2 PT1000 put on the lateral surface • P=0.5 W DT=30 mK • Resolution around 500 mK • Bad data reproducibility • Not depending on • Power losses by radiative emission • PT1000 calibration • Hidden reason under investigation • Bad electrical contacts?
Facility for Q measurementsGeNS: a Gentle Nodal Suspension • Simple but innovative idea • Thickness < diameter stable equilibrium • Advantages w.r.t. other methods • No clamp • Allows to test coated samples • Minimize the contact surface • Independent relevant parameter estimation • Disk-sphere friction • Surface roughness • Q-dependence on suspension centering
Facility for Q: GeNS at work • 4.75 ø mm steel ball bearing • 15 mm diameter contactsurface (estimated) • Optical lever readout
Facility for Q: measurements • Samples • HOQ300 fused silica 75 ø mm disks • 1÷3 mm thickness • Normal/special surface working (parallelism) • Flamed/unflamed lateral surface • Q vs frequency (residual pressure ≈ 10e-5 mbar)
Measured Q in millions Facility for Q: measurements • Q versus vacuum chamber pressure • Q versus suspension position • 1.3 mm displacement precision ( → 2mm on the target screen) • Reproducibility around 3% even after a month
Heating wires for RC temperature control 0.1 K 1 h Facility for small displacement • Fluctuation below 0.01 K needed • Few mK stability reached
Future work • Facility for k • Characterization of Si-bonding influence on the thermal conductance • Facility for Q • Characterization of GeNS with measurement on Suprasil 311 • Coated sample investigation • Facility for a • Complete setup