Task M2 – Advanced Materials and Techniques for Resonant Detectors Motivation : Reduce thermal noise contribution to the acoustic detector noise budget.

Task M2 – General Strategy A) Reduce thermal noise power spectrum 1)Find the materials with the lowest mechanical and/or electrical dissipation and suitable to be cooled down at cryogenic temperatures (Mo,Be,SiC,CuAl,….) 2)Find the assembling and joining procedures that preserve the Q- factor of the material (explosion welding, silica bonding…)

Task M2 – General Strategy B) Reduce the relative contribution of thermal noise (i.e. increase the transducer efficiency  ) Surface treatments, two faces transducer,.. For the capacitive transducer:  is proportional to the Electric bias field For the optical transducer:  is prop. to the laser Power 1/2 time the Finesse  is prop. to the laser Power 1/2 time the Finesse

Task M2 – Advanced Materials and Techniques for Resonant Detectors Main outcomes : - Construction and test of high sensitivity and of low loss capacitive and optical displacement transducers - -Low temperature measurement of the mechanical Q, thermal expansion and heat capacity of several materials (Mo,Be,CuAl,SiC…). -Find joining procedures (electron beam, explosion beam welding, silicate bonding) and surface treatment which preserve high Q-factors. - Low temperature measurement of dielectric losses.

Task M2 – Advanced Materials and Techniques for Resonant Detectors Working GroupFacility used for M2Expertise for M2 INFN ROG MAT Cryogenic facility for testing mechanical and electromechanical resonators Low loss materials, low temperature Q measurements INFN Virgo MAT Clean rooms, Q measurement facilities, mechanical properties measurement facility, hard material milling machine Low loss suspensions, silicate bonding technology, thermal noise, interferometry INFN AURIGA LNL Ultra low temperature test facility for mechanical and optical displacement sensors Cryogenics, interferometry, low loss materials IFN Ultra low temperature test facilityFEM, low loss matching networks for SQUID amplifiers Leiden Ultra low temperature test facilityUltra low temperature technology, low loss electromechanical transducers IGR MAT Q measurements facilities and clean room Low loss suspensions, bonding, thermal noise, interferometry

9.JRA3 First 18 months Implementation Plan Tasks and Deliverables1 st to 6 th month7 th to 12 th month13 th to 18 th month WP 1 - Task M2: Advanced materials and techniques for resonant detectors Tasks: Construction of first CuAl, SiC and Be resonators Construction of first optical and cap. transducers Low T and low frequency, Q measurements on CuAl, SiC and Be Test of a metallic trans. on a resonant sphere Effect of the dieletric coating on the thermal noise Experiments on limiting bias electric fields in the capacitive transducer Upgrade of suspension performance of test facility Surface loss measurements at low temperature after chemical treatment Q of silicate bonding on SiC at low T (as part of improving fab. processes) Deliverables: - CuAl, SiC and Be resonator prototypes - Optical and capacitive transducer prototypes

M2.1 - M2.1 - Construction of first CuAl, SiC and Be resonators Working groups Rog, Auriga LNL,Leiden Working groups Rog, Auriga LNL,Leiden Be Hot Isostatic Pressure (ROG,LNL) Mo CuAl (ROG,Leiden) “Pure” resonators Transducer resonators Apr04-Sep04

M2.1 - M2.1 - Construction of first CuAl, SiC and Be resonators Working groups Auriga LNL, IFN Working groups Auriga LNL, IFN C/SiC resonator: status “..The size of the structures that can be manufactured is limited by the scale of the currently available facilities (3mx3mx4m)...” Best geometry under investigation

M2.3 - M2.3 -Low T and low frequency, Q measurements on CuAl, SiC and Be Optical read-out (ready) Working groups Leiden, Auriga LNL, IFN, ROG Working groups Leiden, Auriga LNL, IFN, ROG Apr04-Sep05 the last stage of suspension has to be designed and tested with high Q resonators First results for CuAl resonators: Q 300K =20000, Q LN2 =(3-5)x10 4, Q LHe4 =(5-10)x10 5 For the other materials measurements will be done at LNL: Capacitive read-out (for metal samples)

M2.3 - M2.3 -Low T and low frequency, Q measurements on CuAl, SiC and Be LNL Cryogenic test facility, optical readout

M2.2 -Construction of Optical and Capacitive transducers Optical Transducer: Working groups Auriga Fi,Pd,LNL Construction of the optical transducer is complete Low T Q-factor measurements in the TTF Apr04-Sep04 Only Resonator Assembled

M2.2 -Construction of Optical and Capacitive transducers M2.2 -Construction of Optical and Capacitive transducers Optical Transducer: Next step (Spring 2005) Up-grading

M2.2 -Construction of Optical and Capacitive transducers Capacitive Transducer: Working groups Leiden, Rog Many Capacitive transducer has been constructed Apr04-Sep04 ROG Leiden Rosetta Transducer, CuAl, gap 15  m, freq= 3200 Hz Rosetta Transducer, CuAl, gap 15  m, freq= 3200 Hz Double face transducer, Al5056, freq=920 Hz Double face transducer, Al5056, freq=920 Hz Rosetta Transducer Rosetta Transducer Drum Transducer + Bolt free assembling Drum Transducer + Bolt free assembling MiniGrail Transducer

M2.4 M2.4 Test of a metallic transd. on a resonant sphere Oct04-Dec05 Working groups Leiden, ROG Working groups Leiden, ROG T= 5 K MiniGrail Thermal noise dominated at 5K SQUID output PSD

M2.5 M2.5 Effect of the dielectric coating on the thermal noise Working groups Rog,IFN, Leiden, Auriga LNL Working groups Rog,IFN, Leiden, Auriga LNL Apr05-Dic05 1.Electric losses: measure of the electrical quality factor of a cryogenic LC resonator. The dielectric under investigation fills the capacitor gap. Sensitivity of the existing apparatus (IFN)  = Mechanical losses: measure the quality factor of transducers having dielectric coating. The available facilities are ROG, Leiden, LNL

M2.6 M2.6 - Experiments on limiting bias electric fields in the capacitive transducer Working groups Leiden, IFN, Auriga LNL Working groups Leiden, IFN, Auriga LNL Typical value for operating detectors MV/mTypical value for operating detectors MV/m Best result 25MV/m Leiden-MiniGrail July 2004Best result 25MV/m Leiden-MiniGrail July 2004 Test of surface treatment on small sample (goal 100 MV/m).Test of surface treatment on small sample (goal 100 MV/m). Oct04-Dic05 Experimental set-up (ready) Samples (ready) -Al5056 -Diameter 3 cm -Single point diamond turning (optical quality) -Dielectric coating (if need) still to be done

M2.9 M2.9 - Q of silicate bonding on SiC at low T (as part of improving fabrication processes) Apr05-Dec05 Working groups Auriga LNL, Virgo MAT, IGR MAT Working groups Auriga LNL, Virgo MAT, IGR MAT Assemble the resonators using silicate bonding and then measure the mechanical quality factor Silicate Bonding

Task M2 – Advanced Materials and Techniques for Resonant Detectors Conclusions 1.Almost all the objective of the first 6 months as been obtained. 2.According to the time schedule the second part of the program has begun.