RF power sources for JLC

RF power sources are a key problem to be solved for the next generation linear colliders. The candidates are mainly divided into two categories. One includes conventional power sources such as klystron, crossed field amplifier, gyrocon, and lasertron while the second approach is the two beam scheme, such as super conducting RF of CLIC project in CERN, and induction linacs at LBL, LLNL and in KEK. For the JLC (Japan Linear Collider) project, the elementary design work must be completed in 1993, and this time limit leads to the conclusion that the effort to develop RF power sources must be concentrated on conventional power sources. The first part of this program has already been carried out. The first test diode tube, named XB-50D, was fabricated in May 1989 and pulsed test operation has been performed up to the cathode voltage of 450 kV. The report describes major results of the XB-50D diode test, focusing on its aging history, the cathode voltage and the beam current. The design of a 30 MW klystron, XB-50K, was implemented in 1989. For the design of the main linacs, at least 100 MW RF power with a pulse duration of 400 nsec is of absolute necessity. With such 100 MW klystrons, a RF pulse compression scheme will be essentially necessary for constructing RF power sources for the JLC X-band linacs. (N.K.)