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Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider

The two-stage (TS) multibeam klystron (MBK) technology has recently attracted significant research attention due to its compactness and high-efficiency (HE) performance. However, there is still a lack of scientific research on the beam optics for such microwave power sources integrated with a postac...

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Autores principales: Cai, Jinchi, Nisa, Zaib un, Syratchev, Igor, Burt, Graeme
Lenguaje:eng
Publicado: 2022
Materias:
Acceso en línea:https://dx.doi.org/10.1109/TED.2022.3182299
http://cds.cern.ch/record/2826897
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author Cai, Jinchi
Nisa, Zaib un
Syratchev, Igor
Burt, Graeme
author_facet Cai, Jinchi
Nisa, Zaib un
Syratchev, Igor
Burt, Graeme
author_sort Cai, Jinchi
collection CERN
description The two-stage (TS) multibeam klystron (MBK) technology has recently attracted significant research attention due to its compactness and high-efficiency (HE) performance. However, there is still a lack of scientific research on the beam optics for such microwave power sources integrated with a postacceleration (PA) gap. In this article, a comprehensive optics study based on the newly developed 2-D optics code CGUN is conducted for the first time to demonstrate the most critical steps in the optics design process, by adopting the 400-MHz TS MBK for the future circular collider (FCC) as an example. Two specific challenges arise in this TS MBK, which are studied in this article, and solutions are given. First, due to the combination of slow electrons, impedance change from individual beamtubes into common volume, and the mild decay of the magnetic field, there are possible reflected electrons at the collector entrance. This requires an increase in the beam voltage to 80 kV, beyond the requirements from considering the output gap alone, as well as tighter control on bouncing electrons. The beam scalloping is also found to be highly sensitive to the position of the PA gap and magnetic field, which later demonstrates that large gap length and magnetic field are required. Final all-in-one particle-in-cell (PIC) simulations of this klystron equipped with this special optics design demonstrate that the specification of 1.2-MW continuous wave (CW) power is practically attainable with an efficiency of 77.5% and without the presence of reflected electrons at any point in the whole circuit.
id cern-2826897
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2022
record_format invenio
spelling cern-28268972022-09-15T09:31:49Zdoi:10.1109/TED.2022.3182299http://cds.cern.ch/record/2826897engCai, JinchiNisa, Zaib unSyratchev, IgorBurt, GraemeBeam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular ColliderAccelerators and Storage RingsThe two-stage (TS) multibeam klystron (MBK) technology has recently attracted significant research attention due to its compactness and high-efficiency (HE) performance. However, there is still a lack of scientific research on the beam optics for such microwave power sources integrated with a postacceleration (PA) gap. In this article, a comprehensive optics study based on the newly developed 2-D optics code CGUN is conducted for the first time to demonstrate the most critical steps in the optics design process, by adopting the 400-MHz TS MBK for the future circular collider (FCC) as an example. Two specific challenges arise in this TS MBK, which are studied in this article, and solutions are given. First, due to the combination of slow electrons, impedance change from individual beamtubes into common volume, and the mild decay of the magnetic field, there are possible reflected electrons at the collector entrance. This requires an increase in the beam voltage to 80 kV, beyond the requirements from considering the output gap alone, as well as tighter control on bouncing electrons. The beam scalloping is also found to be highly sensitive to the position of the PA gap and magnetic field, which later demonstrates that large gap length and magnetic field are required. Final all-in-one particle-in-cell (PIC) simulations of this klystron equipped with this special optics design demonstrate that the specification of 1.2-MW continuous wave (CW) power is practically attainable with an efficiency of 77.5% and without the presence of reflected electrons at any point in the whole circuit.oai:cds.cern.ch:28268972022
spellingShingle Accelerators and Storage Rings
Cai, Jinchi
Nisa, Zaib un
Syratchev, Igor
Burt, Graeme
Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider
title Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider
title_full Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider
title_fullStr Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider
title_full_unstemmed Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider
title_short Beam Optics Study on a Two-Stage Multibeam Klystron for the Future Circular Collider
title_sort beam optics study on a two-stage multibeam klystron for the future circular collider
topic Accelerators and Storage Rings
url https://dx.doi.org/10.1109/TED.2022.3182299
http://cds.cern.ch/record/2826897
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AT nisazaibun beamopticsstudyonatwostagemultibeamklystronforthefuturecircularcollider
AT syratchevigor beamopticsstudyonatwostagemultibeamklystronforthefuturecircularcollider
AT burtgraeme beamopticsstudyonatwostagemultibeamklystronforthefuturecircularcollider