PPM Focused X-Band Klystron Development at the Stanford Linear Accelerator Center

X-band klystrons capable of 50 MW and utilizing Periodic Permanent Magnet (PPM) focusing are undergoing design and fabrication at the Stanford Linear Accelerator Center (SLAC). The klystron development is part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). The first klystron to be tested this year has a 0.6 UK beam at 465 kV, a 5-cell traveling-wave output structure and a predicted efficiency of 63%. A 465 kV, 190 Abeam-stick with 12 periods of PPM focusing has recently operated to verify the gun optics and transmission of the beam in the absence of rf bunching. Beam transmission greater than 99.8%. has been measured. Design and simulation of the beam-stick and klystron are discussed along with performance of the beam-stick under confined-flow and shielded conditions.