Accelerator Seminar: Valery Shemelin

Conference Date
Conference Location

CC F326-327

Speaker: Valery Shemelin, Cornell University

Title: Optimization of Superconducting Cavities: Shape, Fields, Multipactor

Abstract: A method is discussed to search geometrical parameters of elliptical cavities to obtain the best possible figures of merit: B_pk/E_acc (peak magnetic field) and GR/Q (losses) for a given E_pk/E_acc (peak electric field), aperture, wall slope angle. The result of this search is the reentrant cavity with a record acceleration rate of 59 MeV/m with the aperture radius of 30 mm and 52 MeV/m with 35 mm. Further improvement in optimization is offered – equidistant optimization, that makes clear the dependence of maximal acceleration gradient on the limiting electric and magnetic field. Use of specially developed software – TunedCell on the base of SuperLANS - made possible to find best geometries of cavities in a 4D space of parameters.An overview of different multipactor kinds is presented, zones of 1-point and 2-point multipactor in elliptical cavities are described, and a method to search for multipactor–free geometries is offered.