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OPR04 |
Electron Cloud Build Up and Instability in DAΦNE
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A strong horizontal instability limiting the positron current has been observed at DAΦNE since the installation of the FINUDA detector in 2003. Experiments and simulations seem to provide an evidence that the electron cloud build-up in the wigglers and bending magnets of the DAΦNE positron ring induces a coupled bunch instability with features compatible with observations . To better understand the electron cloud effects and possibly to find a remedy, a detailed simulation study is undergoing. In this communication we present recent simulation results relative to the build up of the electron cloud, also taking into account the effect of clearing electrodes in the dipoles and wigglers of the DAΦNE positron ring. The resulting electron cloud distribution is used to study both coupled and single bunch induced instabilities.
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Slides
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MIT03 |
Experimental Efforts at LNF to Reduce Secondary Electron Yield in Particle Accelerators
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46 |
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- R. Cimino, M. Commisso, T. Demma, D. Grosso
INFN/LNF
- N. Mahne, A. Giglia
CNR-IOM
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A common effort in most of the accelerator centers is to develop new technologies to produce and test beam pipe inner walls of particle accelerators with an as low as possible Secondary Electron Yield (SEY). This item, in fact, is crucial in controlling Electron Cloud formation and in reducing its effects, that are well known to be a potential bottle-neck to the performances obtainable from present and future accelerators. Frascati has a longstanding experience in qualifying materials in terms of surface parameters of interest to e-cloud issues. We are routinely measuring SEY, its dependence from electron energy, temperature and scrubbing and we are about to be ready to study not only Photo Electron Yield (PEY) by using synchrotron radiation beamlines in construction at DAΦNE, but more importantly, to characterize in situ the surface chemical composition and eventual modifications occurring during electron or photon irradiation. Such characterization effort is also suggesting ways to produce Low SEY materials. Some preliminary results will be here discussed.
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Slides
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