Pallation neutron source 2.5 MW (402.5 MHZ), and 5 MW (805 MHZ) klystron transmitter systems

The Spallation Neutron Source (SNS) being built at the Oak Ridge National Lab (ORNL) in Tennessee includes a one GeV proton linac, which requires 3 distinct types of RF systems. The radio frequency quadrapole (RFQ) and the drift tube linac (DTL) have 2.5-MW peak, 402.5 MHz, klystron transmitters installed. The coupled-cavity linac (CCL) and the two high energy beam transport (HEBT) cavities utilize 5-MW peak, 805 MHz klystron transmitters. The superconducting linac (SCL) has 550-kW peak, 805 MHz klystron transmitters. This paper will describe the design, fabrication and testing of the 2.5-MW and 5-MW transmitters, each of which includes a klystron control console, a single klystron supporting high voltage enclosure, and a six circuit klystron cooling metering cart. The 550-kW transmitter is described in an accompanying paper to be presented at this conference D. Gapp 2004. Two tailored hardware versions (402.5 MHz and 805 MHz transmitters) of a common baseline design used to meet the specified goals of a megawatt class RF transmitter system are presented. Features of the hardware installed at Los Alamos National Laboratory (LANL), such as interlocks, PLC fault logging and the real-time interface to the linac´s data archive system are described. Design and fabrication of a compact, high reliability, klystron filament isolation transformer with totally shielded primary and secondary windings is discussed.