| Paper | Title | Page |
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| TUP25 | Simulation and Measurements of the Fast Faraday Cups at GSI UNILAC | 286 |
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Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05P21RORB2. Joint Project 05P2021 - R&D Accelerator (DIAGNOSE) The longitudinal charge profiles of the high intensity heavy ion beam accelerated at the GSI UNILAC upto 11.4 MeV/u can differ significantly in consecutive macro-pulses. Variations in bunch shape and mean energy were also observed within a single macro-pulse. In order to have an accurate and fast determination of bunch shape and its evolution within a macro-pulse, a study of fast Faraday Cup designs is underway at GSI. In this contribution, we present CST particle in cell (PIC) simulations of radially coupled co-axial Fast Faraday Cup (RCFFC) and conventional axially coupled FFC (ACFFC) design. The simulation results are compared to the measurements performed under comparable beam conditions primarily with RCFFCs. A rather large impact of secondary electron emission is observed in simulations and experiments. The biasing of the FFC central electrode as a mitigation mechanism on the measured profiles is discussed. |
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| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP25 | |
| About • | Received ※ 15 September 2022 — Revised ※ 17 September 2022 — Accepted ※ 25 October 2022 — Issue date ※ 02 November 2022 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| WEP28 | Studies on Radially Coupled Fast Faraday Cups to Minimize Field Dilution and Secondary Electron Emission at Low Intensities of Heavy Ions | 460 |
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Fast Faraday Cups (FFCs) are interceptive beam diagnostic devices used to measure fast signals from sub-nanosecond bunched beams and the operation of these devices is a well-established technique. However, for short bunch length measurements in non-relativistic regimes with ion beams, the measured profile is diluted due to field elongation and distortion by the emission of secondary electrons. Additionally, for short bunches with the expected intensities envisaged in the High Current Injector at the Inter University Accelerator Centre, the impedance matching of the EM structure puts severe design constraints. This work presents a detailed study on the modification of a radially-coupled coaxial FFC [1]. The field dilution and secondary electron emission aspects are modelled through EM simulations and techniques to minimise these effects are explored. This has resulted in a new design, which has a better signal to noise ratio and benefits from a more accurate bunched beam measurement.
[1] Carneiro, J.-P., et al. ’Longitudinal Beam Dynamics Studies at the Pip-II Injector Test Facility.’ International Journal of Modern Physics A, vol. 34, no. 36, 2019, p.1942013 |
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| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-WEP28 | |
| About • | Received ※ 03 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 25 October 2022 — Issue date ※ 28 November 2022 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |