ESS Medium and High Beta Cavity Prototypes

In the framework of the ESS activity in progress at INFN-LASA, we are designing and developing 704.42 MHz Medium (β=0.67) and High (β=0.86) beta prototype cavities plug compatible with the ESS cryomodule design. The cells of one Medium and one High beta cavity are fabricated with high quality CBMM Large Grain Niobium (480 mm dia. Ingot, RRR=300, sliced by Heraeus) while a Medium beta cavity is done with Fine Grain material for comparison. The prototype cavities will be produced by the firm Ettore Zanon S.p.A. under the supervision of INFN LASA group.