Meander-line current structure for SNS fast beam chopper

A new current structure for the fast traveling-wave 2.5 MeV beam chopper for the Spallation Neutron Source (SNS) project has been proposed. It is based on the meander-folded straight or notched stripline with separators. Detailed electromagnetic modeling with MAFIA has been used to optimize the structure design and parameters. The time-domain 3D MAFIA simulations predict the structure rise and fall times around 1 ns. A notched meander line with a dielectric substrate has been developed to accommodate both electromagnetic and mechanical requirements.