Simulation of traveling-wave output structures for high power rf tubes
Travelling wave output structures can in principle provide higher efficiency and lower surface gradients than a single output cavity. We discuss simulations of TW structures designed for X-band klystrons to be used in the SLAC NLC. The PIC Code CONDOR calculated efficiency over 50 percent for one such circuit. When the circuit was built in the SLAC XC7 klystron, the match was so poor that it had to be modified. When tested, the tube produced less than half the efficiency calculated. We subsequently found significant differences between the field distribution calculated by CONDOR versus that from the 3-D code MAFIA. We have now developed a procedure which gives much better agreement between the 2D and 3-D models. We use a {pi}/2 disk-loaded structure, with the waveguide coupling to an output cavity through an iris, rather than directly to the drift tube as in the XC7. The disk radii are tapered to produce an approximately constant gradient. The output coupling is adjusted to match to a uniform structure replicating the cell before the waveguide. The simulations predict 75 MW, 49 percent efficiency, with peak surface fields of 73 MV/m. from a 440 kV, 350 amp beam at 11.424 GHz.
- Research Organization:
- Stanford Linear Accelerator Center, Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 10187064
- Report Number(s):
- SLAC-PUB-6234; CONF-930511-435; ON: DE93041005; TRN: 93:021852
- Resource Relation:
- Conference: PAC `93: international particle accelerator conference,Washington, DC (United States),17-20 May 1993; Other Information: PBD: Apr 1993
- Country of Publication:
- United States
- Language:
- English
Similar Records
A ppM-focused klystron at X-band with a travelling-wave output structure
A PPM-focused klystron at X-band with a traveling-wave output structure