Klystron studies using polarization variables

A computer program utilizing a system of polarization variables has been developed at the Stanford Linear Accelerator Center. This system differs from other variable systems because of its capacity to reduce and isolate the non-linearities in large signal klystron interaction theory calculations. This paper will discuss the basic idea behind polarization variables and discuss some interesting aspects of space charge, beam loading and output cavity impedance on the accuracy of analysis and required computation time of the program. The algorithm was designed to include relativistic effects and has been used for analysis on a broad range of klystrons at the accelerator center. The code has not only given Us confidence in its use as an analytic tool but has also allowed us to obtain our primary goal, that of designing and building state-of-the-art klystrons with peak power outputs in excess of 40 MW at 270 kV, and approaching 60 MW at 300 kV, with efficiencies well in excess of 50%. Excellent correlation between experimental and computed results has been obtained for other tube designs as well and will be presented.