LANSCE DTL LONGITUDINAL FIELD MEASUREMENTS AT HIGH- POWER*

Shifts in proton beam tuning were observed in the DTL portion of the Los Alamos Neutron Science Center (LANSCE) Accelerator corresponding with cooling system obstructions during the 2003 operational cycle. A diagnostic system was developed to measure longitudinal field changes at the operational field levels to confirm the source of the tune shifts and track the effectiveness of cooling system repairs. This paper describes the diagnostic system and the results of field distribution measurements at high RF power in the accelerating structures.