An analysis on electric fields and effective voltage in single-gapped klystron cavity

Although the operating frequency of usual linear accelerators was S-band, X-band 100 MW class pulsed klystrons for next generation linear colliders are under development in several countries. 1D simulation codes like JPNDlSK can predict performances of S-band klystrons but do not agree with measured values of the X-band klystrons. So 2.5D codes like CONDOR and MAGIC are necessary for designing new X-band tubes. In this paper the author points out the reason why ID simulation code cannot obtain a good agreement with measured results of X-band klystrons from the view point of cavity field analysis.