• J.T.M. Lyles, S. Archuletta, N.K. Bultman, Z.C. Chen, J. Davis, A.C. Naranjo, D. Rees, G. M. Sandoval, Jr., D.S. Warren
  LANL, Los Alamos, New Mexico
• D. Baca, R.E. Bratton, R.D. Summers
  Compa Industries, Inc., Los Alamos, New Mexico

An major up­grade is re­plac­ing much of the 40 year-old pro­ton drift tube linac RF sys­tem with new com­po­nents at Los Alam­os Neu­tron Sci­ence Cen­ter (LAN­SCE). When in­stalled for the LAN­SCE-R pro­ject, the new sys­tem will re­duce the total num­ber of elec­tron power tubes from twen­ty-four to eight in the RF pow­er­plant. A new 200 MHz high power cav­i­ty am­pli­fi­er has been de­vel­oped at LAN­SCE. This 3.2 MW final power am­pli­fi­er (FPA) uses a Thales TH628 Di­acrode, a state-of-the-art tetrode that elim­i­nates the large anode mod­u­la­tor of the tri­ode-based FPA that has been in use for four decades. Drive power for the FPA is pro­vid­ed by a new tetrode in­ter­me­di­ate power am­pli­fi­er and a sol­id-state driv­er stage. The new sys­tem has suf­fi­cient du­ty-fac­tor ca­pa­bil­i­ty to allow LAN­SCE to re­turn to 1 MW beam op­er­a­tion. Pro­to­type RF power am­pli­fiers have been de­signed, fab­ri­cat­ed, and as­sem­bled and are being test­ed. High volt­age DC power be­came avail­able through in­no­va­tive re-en­gi­neer­ing of an in­stalled sys­tem. De­tails of the elec­tri­cal and me­chan­i­cal de­sign of the FPA and an­cil­lary sys­tems are dis­cussed. Power test re­sults have val­i­dat­ed the de­sign and con­struc­tion of this very high power am­pli­fi­er sys­tem.