Design of the KEKB RF system

Transient beam loading effects in harmonic rf systems for light sources

“…Most recent studies have looked at synchronous phase transients in high current electron-positron colliders [12][13][14][15] and in harmonic rf systems [8,16]. For small perturbations in the voltage along the bunch train, one can estimate the transient bunch synchronous phase by…”

An accelerator resonantly coupled with an energy storage (ARES) for the KEKB

“…Second, the storage cavity has only one mode, or, practically speaking, the TE015 mode is well separated from the other modes. Since neither assumption is correct, we have carefully studied these two effects, using the coupledresonator model calculation for the first problem [2] and a three-dimensional analysis for the second one [3]. The result was quite promising, although an extensive study was necessary in order to sufficiently separate the TE015 mode from the other modes.…”

“…At this conference the development of the KEKB roomtemperature (normal-conducting) RF system is being systematically reported in detail. The newly invented accelerating cavity [1][2][3] will be used for this system. This cavity, refered to as "an accelerator resonantly coupled with an energy storage (ARES)," is actually a coupled-cavity system comprising three cavities: an acclerating cavity (acavity) and an energy-storage cavity (s-cavity) with a coupling cavity (c-cavity) in between (see Fig.…”

“…The total consistent set of RF parameters for the KEKB is presented in Ref. [5], showing that ARES can meet the requirements for the KEKB.…”

B-Factory commissioning and first result

“…On the other hand, due to its high gradient, a superconducting cavity has a large stored energy by itself. These large stored energies of cavities effectively suppress the coupled-bunch instabilities due to the fundamental mode of cavities [8]. At PEP-II, the coupledbunch instabilities due to the fundamental mode of cavities are damped by using RF feedback with comb filters [9].…”