Title: RRR Niobium Seamless Cavities
Author: Roy Crooks
Institution: Black Laboratories
Abstract: Roy Crooks, Black Laboratories, L.L.C., Newport News, VA, USA
Waldemar Singer, DESY, Hamburg, Germany
Conventional welding of half-cells deep-drawn from niobium sheet may generate flaws near the cavity equators which limit cavity performance. Cavities have been produced from RRR niobium tube by a combination of spinning and hydroforming, using the facilities at DESY. Seamless cavities were manufactured from tubes produced by two different methods, based on pipe spun from plate and on pipe back-extruded from ingot (at ATI Wah Chang). The microstructures resulting from the two fabrication methods are described, along with SRF properties from recent tests on prototype ILC cavities.