A 17 GIGAHERTZ TRAVELING WAVE RELATIVISTIC KLYSTRON FOR HIGH GRADIENT ACCELERATORS

PARAMETRIC STUDIES OF NEXT-GENERATION ELECTRON LINEAR COLLIDERS AND RESULTS PRESENTED DURING THE LAST THREE INTERNATIONAL WORKSHOPS CONTINUE TO SUPPORT EARLIER CONTENTIONS THAT THE MOST FAVORABLE CHOICE OF LINAC FREQUENCY IS IN THE RANGE OF 10 TO 20 GHZ, WITH PARTICULAR INTEREST IN THE UPPER END OF THE BAND. ALTHOUGH CONSIDERABLE INTEREST EXISTS IN 17 GHZ LINEAR COLLIDER CONCEPTS-AND SOME RESEARCH ACTIVITIES ARE ALREADY IN PROGRESS AT BROOKHAVEN NATIONAL LABORATORY AND MASSACHUSETTS INSTITUTE OF TECHNOLOGY (AND IN PRIVATE LABORATORIES INTERESTED IN COMMERCIAL APPLICATIONS OF HIGH FREQUENCY LINACS)-THERE ARE NO RELATIVISTIC KLYSTRONS (RK) PRESENTLY AVAILABLE TO SUPPORT 17 GHZ HIGH GRADIENT ACCELERATOR RESEARCH. (LINEAR COLLIDER RK DEVELOPMENT IS AT 14 GHZ IN RUSSIA AND AT 11.4 GHZ IN THE UNITED STATES AND JAPAN). THE OBJECTIVE OF THIS PROJECT IS TO STUDY MEANS OF COMBINING RESEARCH ON HIGH POWER TRAVELING WAVE RELATIVISTIC KLYSTRON (TWRK) STRUCTURES; LONG RADIO FREQUENCY (RF) PULSE CIRCUIT DEVELOPMENT; AND THE AVAILABILITY OF AN EXISTING 580 KV, 120 A, 1 MUS PULSED-BEAM TEST FACILITY. REACHING THIS OBJECTIVE WILL ALLOW THE ESTABLISHMENT OF AN INEXPENSIVE PROGRAM FOR THE DESIGN, FABRICATION, AND TESTING OF A NEW RF SOURCE SUITABLE FOR HIGH GRADIENT 17 GHZ ACCELERATOR RESEARCH. PHASE I IS EXPLORING THE FEASIBILITY OF EXTENDING TO 17 GHZ NEW DESIGN CONCEPTS ASSOCIATED WITH A RECENTLY DEMONSTRATED 43% CONVERSION EFFICIENCY, 100 MW, 11.4 GHZ RK USING A NOVEL SLOW WAVE OUTPUT STRUCTURE. SPECIAL DESIGN EMPHASIS IS BEING DIRECTED AT ACHIEVING A GAIN OF 60 DB AND AN EFFICIENCY OF >48% WITH A PROTOTYPE 30 MW TUBE. IN PHASE II, THE 17 GHZ TWRK AND ITS HIGH POWER RF DIAGNOSTIC EQUIPMENT WILL BE CONSTRUCTED AND INSTALLED IN THE TEST FACILITY, LONG PULSE HIGH POWER RF TESTS WILL BE PERFORMED, AND THE INTEGRITY AND SUITABILITY OF THE TUBE WILL BE EVALUATED. IT IS EXPECTED THAT THIS LOW PERVEANCE, HIGH EFFICIENCY TWRK COULD BE A STRONG CANDIDATE FOR A LINEAR COLLIDER PULSE COMPRESSION POWER SOURCE.