Speaker
Description
At KEK, fireball-triggered RF breakdowns [1] have been observed in 509-MHz normal-conducting accelerating cavities. It has been found that the breakdown was caused by a high-temperature microparticle that we call “fireball” now. Recently, the fireball-triggered breakdown attracts interests again in relation to the SuperKEKB accelerator that is suffering from sudden beam losses. A hypothesis is proposed that similar phenomena with the fireball breakdown could cause the sudden beam losses [2]. Because of such growing interests, we have started experimental study of the fireball-triggered breakdown in the accelerating cavity, again. In this study, we are trying to observe more detailed characteristics of the fireball-triggered breakdown, such as the emitted total current at the moment of breakdown. Furthermore, using the Particle-in-Cell simulation of CST Studio Suite, we are trying to reproduce the breakdown phenomena observed in the experiment. The results will be useful for better understanding the mechanism of the sudden beam loss in SuperKEKB. In this workshop, we report the initial experimental and simulation results.
[1] T. Abe, et al., Phys. Rev. Accel. Beams 21, 122002 (2018).
[2] T. Abe, this workshop.
