Development of a Prototype Niobium SRF Cavity for the PEFP Proton Superconducting Linac

A superconducting linac is one of the extension options for the 100-MeV proton linac for the Proton Engineering Frontier Project (PEFP). For the basic study on the RF superconducting linac, we have developed a prototype cavity of elliptical shape with a geometrical beta of 0.42. The main purposes of the prototype cavity fabrication are to confirm the design, to check the fabrication procedure, and to gain some manufacturing experiences with the niobium cavity. The details of the prototyping and the test results will he given in this paper.