Conveners
M3Or1C - Focus Series C: Superconducting RF Cavity Materials III
- Karl Hartwig (Texas A&M University)
- Shreyas Balachandran (National High Field Magnet Laboratory)
Cryogenic atomic force microscopy (AFM) allowed us to directly observe segregation morphology of nanometer size hydride phases (Nb1-xHx), which are responsible for Q degradation of superconducting radio frequency (SRF) Nb cavity at high RF field regime. Although niobium hydride has been recognized with cry-optical microscopy, electron diffraction or ion mass spectroscopy, identification of...
Nitrogen-doped niobium is one of the recent keystone advances in the field of SRF accelerator physics: N-doped cavities reach unprecedentedly high efficiency at usable accelerating gradients, and the more recently developed “nitrogen infusion” reaches similar efficiency with even higher accelerating field. On the horizon is niobium-3 tin (Nb3Sn), a superconducting compound that exceeds the...
Nb3Sn is the front running alternative material to replace niobium in SRF cavities. The most promising path toward deployement appears to be the tin vapor diffusion coating of Nb cavity, which had achieved significant progress in recent years. To elucidate the growth kinetics of Nb3Sn coating during this process, niobium samples were coated for different duration up to 60 hours. Several of...
MgB2 is a promising superconductor to replace Nb for SRF cavities. Clean MgB2 thin films have a low residual resistivity (<0.1 µΩcm) and a high Tc of 40 K, promising a low BCS surface resistance. Its thermodynamic critical field Hc is higher than Nb, potentially leading to a higher maximum accelerating filed. The lower critical field Hc1 of MgB2 is lower than Nb, but it can be enhanced by...
