Study of Fast Ion Instability at Kekb Electron Ring
نویسندگان
چکیده
We have studied fast ion instability (FII) in the electron ring (HER) at KEKB. We introduce an application of Singular Value Decomposition (SVD) to study multi-bunch beam oscillations. The SVD analysis[1] has been performed for a matrix consists of vertical bunch positions in a turn-byturn and bunch-by-bunch to extract wave lengths which characterized the behavior of multi-bunch beam instabilities. Multi-bunch beam instabilities were also observed by changing the beam size with adjusting the dispersion function. We found that the multi-bunch beam instabilities were stronger as the beam size decreased. We compared the wave length and growth time with the linear approximate calculation of the FII. Observed multi-bunch beam instability is consistent with the FII.
منابع مشابه
Horizontal Instability in the KEKB HER
After a brief introduction to the problem, I study several aspects related to the horizontal instability in the KEKB HER, namely resistive-wall instability, ion trapping and ion instability, ion losses and the associated modification of the fast beam-ion instability, measurements of coupledbunch oscillations and their simulation assuming they are driven by ions, resistive wall, or electron clou...
متن کاملEUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN-SL-Note-2000-061 AP More Electron Cloud Studies for KEKB: Long-Term Evolution, Solenoid Patterns, and Fast Blow Up
We report recent electron-cloud studies for the Low Energy Ring (LER) of KEKB, continuing earlier investigations [1, 2]. Here we simulate the build up and decay time of the cloud for various solenoid and C-yoke configurations, discuss the electron density enhancement during the bunch passage [3], and estimate the instability threshold using the Ruth-Wang theory of fast blow up [4, 5]. Geneva, S...
متن کاملBeam Tests of a Clearing Electrode for Electron Cloud Mitigation at Kekb Positron Ring*
In order to mitigate the electron cloud instability in an intense positron ring, an electron clearing electrode with a very thin structure has been developed. The electrode was tested with a positron beam of the KEKB B-factory (KEKB). A drastic reduction in the electron density around the beam was demonstrated in a wiggler magnet with a dipole-type magnetic field of 0.78 T. The clearing electro...
متن کاملFast Ion Instability Simulations for CesrTA
In 2008, it has been proposed to convert the Cornell Electron Storage Ring (CESR) into a test accelerator, called CesrTA, for the proposed International Linear Collider (ILC) damping rings. One of the effects to be studied in CesrTA is fast ion instability. An electron beam ionizes residual gas in the vacuum chamber, resulting in positive ions being trapped in the beam’s potential. Fast ion ins...
متن کاملObservation of Transverse Coupled Bunch Instability at Kekb
Transverse coupled bunch instability was experimentally studied in low energy positron ring (LER) and high energy electron ring (HER) at KEKB. The oscillations of bunches were recorded by a bunch oscillation recorder for the total of 4096 turns. The data were analysed to obtain the mode distribution and the growth rate of oscillation. The result of the analysis is presented in this paper.
متن کامل