Coupling impedance measurements of the SNS RF cavity and extraction kicker magnet

The Spallation Neutron Source (SNS) is a high intensity machine with peak currents in the accumulator ring reaching ∼50 A at the 1.4 MW design level. This unprecedented beam intensity necessitates a careful investigation of coupling impedances posing as potential performance limitations. Impedance estimates of accelerator components pointed to the RF cavities and extraction kickers as the major contributors to the impedance budget and extensive measurements were performed on their prototypes. Impedance measurements were performed using the standard wire method.