NEW TECHNIQUE AND RESULTS OF LASER WELDED SCRF CAVITY DEVELOPED AT RRCAT

A new technique to fabricate SCRF cavities with the help of laser welding process has been developed at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, Department of Atomic Energy, India. In this technique, an Nd:YAG laser has been used and welding was performed in inert gas environment in a specially designed welding rig. The advantages of this technique are reduced cost, small heat affected zone, no necessity to weld in vacuum and an enhanced rate of production. The paper describes the technique and fabrication method of a single-cell 1.3 GHz SCRF cavity which was fabricated at RRCAT with this new technique. It also discusses the test results of this cavity which was processed and tested at Fermi Lab, USA (FNAL). The cavity reached an Eacc of 17MV/m with a Q0 of 1.4 x10 10 at 2K after buffered chemical and electro-polishing processing sequence. The cavity was then barrel polished to remove a small weld defect and then electro-polished. In the next test the cavity achieved a quench field of 31.6 MV/m with a Q0 of 1.0 x10 10 .