“Investigation of superconductive materials ” Overview

1. STREGA JRA3WP 1 - Task M3 “Investigation of superconductive materials” Overview Renzo F. Parodi INFN-Genova

2. Collaboration • The INFN_Genoa Group is the only Group involved in the development of the M3-Task. Renzo F.Parodi, ILIAS GW General meeting

3. Long Term Aim • An innovative detector based on superconducting resonant cavities has been proposed. • A key feature of this detection scheme is the very high electromagnetic quality factor that can be obtained in superconducting structures. • The aim is to build cavities using the technique of niobium sputtering on a substrate having high thermal conductivity and low intrinsic mechanical dissipations. • The proof of feasibility of the detector will be essential for the development of advanced superconducting RF detectors with high sensitivity. Renzo F.Parodi, ILIAS GW General meeting

4. Short Term Applications • Superconducting RF cavities are Highly suitable to build RF parameric transducers for Acoustic detectors. • Superconducting RF Cavities can generate fields in the 107 V/m with power dissipation compatible with Ultra-cryogenic operation (.1~1 mW). • The high operating frequencies, and the development of Cryogenic RF electronics in telecommunications, gives “of the shelf” amplifiers with Noise temperature ten times the quantum limit. • The results already obtained in M3 are the basis for the production of an RF parametric transducer to be considered as possible readout on the ROG Sphere. Renzo F.Parodi, ILIAS GW General meeting

5. Design sensitivity -19 10 hmin 6 x 10-21 h < 10-20 over 400 Hz (-1/2) -20 [Hz] 10 (1/2) hh S -21 10 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 Frequency [Hz] Renzo F.Parodi, ILIAS GW General meeting

6. Task M3 ActivitiesFull project Renzo F.Parodi, ILIAS GW General meeting

7. Task M3 Activitiesfirst 36 months Renzo F.Parodi, ILIAS GW General meeting

8. Production of seamless copper cavities • Three copper cavity are built. • Starting from a seamless copper tube • By spinning on a collapsible mandrel Renzo F.Parodi, ILIAS GW General meeting

9. Seamless cavity production Collapsible spinning mandrel (Enzo Palmieri) INFN-LNL Renzo F.Parodi, ILIAS GW General meeting

10. Seamlesscavity production Three cavity are ready Renzo F.Parodi, ILIAS GW General meeting

11. Seamlesscavity production One of the cavities is Today used to test the sputtering setup for the Niobium sputtering film deposition process. The first cavity is usedas a test bed to produce niobium samples at different cavity places The samples are measured for Tc and Bc Renzo F.Parodi, ILIAS GW General meeting

12. Niobium Sputtering • Since the Higher the RF Qel the better is the sensitivity, niobium is the best material for the application. (Qel~1011 already achieved) • Niobium is also a good material from the mechanical point of view (low mechanical losses), but very expensive. • The Low Thermal conductivity when superconducting is also a big problem in our application. • Sputtered niobium films on high thermal conductivity and low mechanical losses material are the solution (when proven successful) Renzo F.Parodi, ILIAS GW General meeting

13. Niobium Film OptimizationCritical Temperature Tc Renzo F.Parodi, ILIAS GW General meeting

14. Niobium Film OptimizationCritical Field Bc Renzo F.Parodi, ILIAS GW General meeting

15. Niobium critical field Renzo F.Parodi, ILIAS GW General meeting

16. Mechanical characterisation of Substrata • The work is under way • We measured the Mechanical properties of the first cavity prototypes. • The test setup is ready and tested • Next step will be the measurement of the niobium and niobium on copper samples and cavities from room temperature to superfluid helium (1.85K). Renzo F.Parodi, ILIAS GW General meeting