Development of the C-band (5712 MHz) 50 MW class PPM klystron

Abstract

Hot isostatic pressing (HIP) technique has been firstly applied to fabricate a magnetic circuit in a PPM klystron. Simply stacking disks of the magnetic stainless-steel (Mag-SUS) and oxygen-free copper (OFC) alternatively, and processing in a HIP vessel filled with pressurized Ar-gas at 1,200-kgf/cm(exp 2) and temperature of 800 C for 2 hours, they were bonded in one block with diffusion bonding. No brazing-alloys were used in this process. After machining the rf-cavities and beam drift-tube on the bonded PPM stack, they were assembled together in one body by means of conventional brazing method. The C-band PPM klystron based on this technique was fabricated in the course of the Linear Collider R & D. Output power of 37 MW was generated with 2.5-microsecond pulse width and 50 pps repetition rate.