Development of X-band PPM klystron for JLC project

The 0.5-TeV JLC project requires about 1800 (/linac) klystrons operating at 75 MW output power with 1.5 /spl mu/s pulse length. Periodic Permanent Magnet (PPM) klystrons are being developed to eliminate the expense and power requirements of the focusing solenoids. KEK has begun a two-year project with Toshiba to produce two PPM klystrons in two stage. The goal is to produce 50 MW output power with efficiency > 50% at 1.5 /spl mu/s pulse length at the first klystron and then to advance to 75 MW with efficiency = 55% at the second one.