Speaker
Description
Los Alamos Neutron Science Center started developing a replacement RF powerplant for the 100 MeV drift tube linac over twenty years ago, as there were lifetime issues with high duty factor (12% DF) operation using the RCA/Burle/Photonis 7835 power triode at 200 MHz. Cathode emission failures were predominantly happening at LANSCE at high average power, as 200 MHz injector linacs at BNL and FNAL run at much lower DF. In 2006, LANSCE reduced beam power to half DF, going from 120 Hz to 60 Hz repetition rate, and remained in that mode to survive until the replacement system was tested, commercialized and installed 8 years later. Prototyping began with test stand construction in 2009, with a LANL-built cavity amplifier working in 2011. This was followed by commercial production of 7 power amplifiers built-to-print with installation in three outages in 2014-2016. The linac returned to full DF in 2014. As the only linac using this tube from Thales, we took a risk with a new tube development at the time. In the subsequent decade of operation, the choice of the Thales TH628L has proven to be a wise decision as four tubes have exceeded 55K hours in operation, with two more with slightly less. Reliability of the amplifiers and supporting infrastructure has exceeded expectations. This talk will discuss details of this work, and share insights on using modern tetrode technology for an old linac.
Work was performed under the auspices of the US Department of Energy by Triad National Security, LLC, under contract 89233218CNA000001.
