CLASSE NEWS |
21 May 2014
Cornell Nitrogen-doped Single Cell SRF Cavity Reaches Record Performance
The Cornell SRF team recently has fabricated, prepared and tested a 1.3 GHz single cell SRF cavity, which reached record high intrinsic quality factors Q
0 at high accelerating fields. To reduce wall losses by the RF fields inside the cavity, the niobium surface layer of the cavity was doped with nitrogen, a procedure originally developed by researchers at FNAL.
In a cavity performance test conducted by graduate student Dan Gonnella, the Cornell cavity reached 2K quality factors of 3.5x10
10 at a very high accelerating field of 30 MV/m. At 1.8K and 30 MV/m, the quality factor climbed above 6x10
10. No other SRF cavity before has reached such high cryogenic efficiency at high accelerating fields in the 30 MV/m range.
The cavity was prepared and tested as part of Cornell's ongoing LCLS_II high Q
0 program, which is led by Prof. Liepe. SRF cavities with high intrinsic quality factors at medium to high fields are of critical importance for future SRF driven linear accelerators. These SRF linacs will operate in continuous mode, and become only feasible with highly efficient (i.e. high Q
0) SRF cavities.
Dan Gonnella is in his third year of PhD studies in the SRF group. His advisor is Matthias Liepe.