Design, fabrication, RF test at 2 K of 1050MHz, β=0.49 single cell large and fine grain niobium cavity

Abstract

BARC is developing a technology for the accelerator driven subcritical system (ADSS) that will be mainly utilized for the transmutation of nuclear waste and enrichment of U233. Design and prototyping of a superconducting medium velocity cavity has been taken up as a part of the ADSS project. The cavity design for β = 0.49, f = 1050 MHz has been optimized to minimize the peak electric and magnetic fields, with a goal of 5 MV/m of accelerating gradient at a Q > 5 × 109 at 2 K. After the design optimization, two single cell cavities were fabricated from polycrystalline (RRR > 200) and large grain (RRR > 96) Niobium material. The cavities have been tested at 2 K in a vertical cryostat at Jefferson Lab and both achieved the performance specifications.