| AVS 58th Annual International Symposium and Exhibition | |
| Vacuum Technology Division | Tuesday Sessions |
| Session VT-TuP |
| Session: | Vacuum Technology Poster Session & Student Poster Competition |
| Presenter: | T. Tajima, High Energy Accelerator Research Organization (KEK), Japan and LANL |
| Authors: | T. Tajima, High Energy Accelerator Research Organization (KEK), Japan and LANL N.F. Haberkorn, Los Alamos National Laboratory L. Civale, Los Alamos National Laboratory E. Valderrama, Alameda Applied Sciences Corporation M. Krishnan, Alameda Applied Sciences Corporation |
| Correspondent: | Click to Email |
Bpen, the magnetic field at which magnetic vortices start to penetrate into Nb films prepared by coaxial energetic deposition (CED) technique was measured with a SQUID magnetometer. Unlike the films prepared by conventional sputtering technique that showed Bpen ~ 94 mT at 2.5 K, the CED films showed Bpen of 180-190 mT at 2.5 K, a value that is very close to the number for bulk Nb used for SRF cavities. This corresponds to an accelerating gradient (Eacc) of approximately 45-48 MV/m for the SRF cavities with Bpeak/Eacc ~ 4 mT/(MV/m) such as those for the European XFEL or the ILC projects. These samples were coated on MgO, Sapphire and Borosilicate with RRR ranging between 21(Borosilicate) and 540 (MgO). The next step will be to coat on copper. If it is possible to fabricate Nb coated copper cavities that have similar performance to bulk Nb high-gradient cavities, this will lead to a significant cost saving since the cost of copper is about 2 orders of magnitude less than Nb. It will also have other benefits such as better thermal stability due to high thermal conductivity of copper and less susceptibility to ambient magnetic field than bulk Nb cavities as has already been shown by LEP Nb/Cu cavities at CERN.