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WEPNEC10 | Investigation on the Ion Clearing of Multi-Purpose Electrodes of BERLinPro | electron, brightness, linac, emittance | 80 |
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High-brightness electron beams provided by modern accelerators require several measures to preserve their high quality and to avoid instabilities. The mitigation of the impact of residual ions is one of these measures. It is particularly important if high bunch charges in combination with high repetition rates are aimed for. This is because ions can be trapped in the strong negative electrical potential of the electron beam causing emittance blow-up, increased beam halo and longitudinal and transverse instabilities. One ion-clearing strategy is the installation of clearing electrodes. Of particular interest in this context is the performance of multi-purpose electrodes, which are designed such that they allow for a simultaneous ion-clearing and beam-position monitoring. Such electrodes will be installed in the BERLinPro facility. In this contribution, we present numerical studies of the performance of multi-purpose clearing-electrodes planned for BERLinPro, i.e. we investigate the behavior of ions generated by electron bunches while passing through the field of the electrodes. Hereby, several ion species and configurations of electrodes are considered. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC10 | ||
About • | paper received ※ 11 October 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020 | ||
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WEPNEC22 | Beam Impedance Study on a Harmonic Kicker for the CCR of JLEIC | impedance, cavity, HOM, kicker | 116 |
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Funding: Work supported by Jefferson Science Associates, LLC under U.S DOE Contract No. DE-AC05-06OR23177 In this report, we present the development of a fast harmonic kicker, a normal conducting deflecting cavity that kicks electron bunches from ERL ring to circulator cooler ring (CCR) in Jefferson Lab Electron Ion Collider (JLEIC). This cavity utilizes 5 harmonic modes to generate a sharp kick to the electron bunch at high frequency of 86.6MHz, which is injection frequency into the CCR. The beam dynamics study and RF design of the hardware was reported in [1],[2]. In this report we present further progress including impedance by higher order mode (HOM) study and mechanical design for fabrication. [1] G. Park, et. al TUPAL068, Proc. of IPAC 2018, Apr 2018, Vancouver, BC Canada [2] G. Park, et. al, Proc. of IPAC2019, May 2019, Melbourne, Australia |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-WEPNEC22 | ||
About • | paper received ※ 30 September 2019 paper accepted ※ 04 November 2019 issue date ※ 24 June 2020 | ||
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THCOWBS03 | System Identification Procedures for Resonance Frequency Control of SC Cavities | controls, operation, cryomodule, linac | 129 |
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Funding: Work supported by Deutsche Forschungsgemeinschaft (DFG): GRK 2128 ’AccelencE’ Energy Recovery Linacs promise superior beam quality: sharper and more intense. To reach these goals, resonance frequency control of the superconducting RF cavities is an important part. In this work, system identification procedures conducted at components of the S-DALINAC (Institute for Nuclear Physics, TU Darmstadt, Germany) are shown. This includes investigations of the piezo tuner’s effect on, e.g., the phase of the accelerating field when a periodic disturbance is applied. The results are compared to simulations of the modelled system and the impact of the applied controller is discussed. |
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Slides THCOWBS03 [0.593 MB] | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-THCOWBS03 | ||
About • | paper received ※ 17 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020 | ||
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THCOWBS06 | Beam Breakup Limit Estimations and Higher Order Mode Characterisation for MESA | cavity, HOM, dipole, cryomodule | 134 |
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Funding: Work supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA+" EXC 2118/2019, through RTG2128 Accelence and by ARIES. MESA is a two pass energy recovery linac (ERL) currently under construction at the Johannes Gutenberg-University in Mainz. MESA uses two 1.3 GHz TESLA type cavities with 12.5 MV/m of accelerating gradient in a modified ELBE type cryomodule in c.w. operation. One potential limit to maximum beam current in ERLs is the transverse beam breakup (BBU) instability induced by dipole HOMs. These modes can be excited by bunches passing through the cavities off axis. Following bunches are then deflected by the HOMs, which results in even larger offsets for recirculated bunches. This feedback can even lead to beam loss. To measure the quality factors and frequencies for the dressed as well as undressed cavities improves the validity of any current limit estimation done. |
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Slides THCOWBS06 [3.256 MB] | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-THCOWBS06 | ||
About • | paper received ※ 18 September 2019 paper accepted ※ 04 November 2019 issue date ※ 24 June 2020 | ||
Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | ||