SUPERFLUID HELIUM TESTING OF A STAINLESS STEEL TO TITANIUM PIPING TRANSITION JOINT

Stainless steel‐to‐titanium bimetallic transitions have been fabricated with an explosively bonded joint. This novel joining technique was conducted by the Russian Federal Nuclear Center, working under contract for the Joint Institute for Nuclear Research. These bimetallic transitions are being considered for use in future superconducting radio‐frequency cavity cryomodule assemblies. This application requires cryogenic testing to demonstrate that this transition joint remains leak‐tight when sealing superfluid helium. To simulate a titanium cavity vessel connection to a stainless steel service pipe, bimetallic transition joints were paired together to fabricate piping assemblies. These piping assemblies were then tested in superfluid helium conditions at Fermi National Accelerator Laboratory test facilities. The transition joint test program will be described. Fabrication experience and test results will be presented.