Progress on the new high power 200 MHz RF system for the LANSCE DTL

The Los Alamos Neutron Science Center (LANSCE) linac accelerates up to 1 mA average of proton current for various applications, including the short pulse spallation neutron source, proton radiography, isotope production and neutron research. Long beam pulses at high current put extreme demands on the drift tube linac (DTL) RF power amplifiers, which were originally installed in 1972. A new RF power system is being developed for increased peak power with higher duty factor. The final power amplifiers use a THALES TH628 Diacrodeo(R) and will not require the large anode modulators used in the present system. The RF amplitude control will be introduced at a low level in the power chain. When completed, the new system will reduce the number of electron power tubes from twenty-four to seven in the RF plant for the 100 MeV DTL. Details of the EM field models, the mechanical layout, prototype construction techniques, RF tests, and system considerations will be discussed.