Multipactoring zone map of an rf input coupler and its application to high beam current storage rings

Multipactoring phenomena in a radio frequency (rf) input coupler, which could cause serious problems during accelerator operation, are described based on electrodynamics with the superposition state of the input and reflected waves in the coupler. Since the reflection coefficient varies widely with the beam loading in the case of high beam current storage rings, multipactoring zones should be represented in the two-dimensional space of the input rf power and the reflection coefficient. Based on this map, we have performed a simulation study for normal-conducting rf accelerating cavities and developed a method to operate an rf cavity with multipactoring problems so as to minimize the influence of multipactoring

Recent Progress at KEKB

We summarize the machine operation of KEKB during past one year. Progress for this period, causes of present performance limitations and future prospects are described

Achievements of KEKB

The machine commissioning of KEKB started in December 1998 and its operation was terminated at the end of June 2010 to upgrade KEKB to SuperKEKB. In this paper, we summarize the history of KEKB and show the achievements made there