2017/01/21 by Anna Grassellino, A. Grassellino, A. Romanenko +19 · 1 citation
Chemistry · Engineering · Physics and Astronomy · #Analytical Chemistry (journal) #Atomic physics #Chemistry #Condensed matter physics #Gyrotron and Vacuum Electronics Research #Impurity #Liquid nitrogen #Materials science #Metallurgy #Niobium #Nitrogen #Optics #Optoelectronics #Particle Accelerators and Free-Electron Lasers #Particle accelerator #Particle accelerators and beam dynamics #Physics #Resonator #Superconducting radio frequency #Superconductivity #physics.acc-ph
paper · pdf · doi:10.1088/1361-6668/aa7afe
arxiv created 2017/01/21 · openalex created_date 2017/02/03 · openalex publication_date 2017/06/22 · arxiv updated 2017/09/13 · openalex updated_date 2026/08/06
We report the finding of new surface treatments that permits one to manipulate the niobium resonator nitrogen content in the first few nanometers in a controlled way, and the resonator fundamental Mattis–Bardeen surface resistance and residual resistance accordingly. In particular, we find surface 'infusion' conditions that systematically (a) increase the quality factor of these 1.3 GHz superconducting radio frequency (SRF) bulk niobium resonators, up to very high gradients; (b) increase the achievable accelerating gradient of the cavity compared to its own baseline with state-of-the-art surface processing. Cavities subject to the new surface process have more than two times the state-of-the-art Q at 2 K for accelerating fields >35 MVm −1 . Moreover, very high accelerating gradients ∼45 MVm −1 are repeatedly reached, which correspond to peak magnetic surface fields of 190 mT, among the highest measured for bulk niobium cavities. These findings open the opportunity to tailor the surface impurity content distribution to maximize performance in Q and gradients, and have therefore very important implications on future performance and cost of SRF based accelerators. They also help deepen the understanding of the physics of the RF niobium cavity surface.