Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures
The objective of this work is the evaluation of the risk of suffering a multipactor discharge in an S-band dielectric-assist accelerating (DAA) structure for a compact low-energy linear particle accelerator dedicated to hadrontherapy treatments. A DAA structure consists of ultra-low loss dielectric...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2024-01-01
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| Series: | Results in Physics |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211379723010380 |
| _version_ | 1827378190468775936 |
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| author | Daniel González-Iglesias Benito Gimeno Daniel Esperante Pablo Martinez-Reviriego Pablo Martín-Luna Nuria Fuster-Martínez César Blanch Eduardo Martínez Abraham Menendez Juan Fuster Alexej Grudiev |
| author_facet | Daniel González-Iglesias Benito Gimeno Daniel Esperante Pablo Martinez-Reviriego Pablo Martín-Luna Nuria Fuster-Martínez César Blanch Eduardo Martínez Abraham Menendez Juan Fuster Alexej Grudiev |
| author_sort | Daniel González-Iglesias |
| collection | DOAJ |
| description | The objective of this work is the evaluation of the risk of suffering a multipactor discharge in an S-band dielectric-assist accelerating (DAA) structure for a compact low-energy linear particle accelerator dedicated to hadrontherapy treatments. A DAA structure consists of ultra-low loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure, with the advantage of having an extremely high quality factor and very high shunt impedance at room temperature, and it is therefore proposed as a potential alternative to conventional disk-loaded copper structures. However, it has been observed that these structures suffer from multipactor discharges. In fact, multipactor is one of the main problems of these devices, as it limits the maximum accelerating gradient. Because of this, the analysis of multipactor risk in the early design steps of DAA cavities is crucial to ensure the correct performance of the device after fabrication. In this paper, we present a comprehensive and detailed study of multipactor in our DAA design through numerical simulations performed with an in-house developed code based on the Monte–Carlo method. The phenomenology of the multipactor (resonant electron trajectories, electron flight time between impacts, etc.) is described in detail for different values of the accelerating gradient. It has been found that in these structures an ultra-fast non-resonant multipactor appears, which is different from the types of multipactor theoretically studied in the scientific literature. In addition, the effect of several low electron emission coatings on the multipactor threshold is investigated. Furthermore, a novel design based on the modification of the DAA cell geometry for multipactor mitigation is introduced, which shows a significant increase in the accelerating gradient handling capabilities of our prototype. |
| first_indexed | 2024-03-08T12:52:23Z |
| format | Article |
| id | doaj.art-6ebde103e03540ff8ac8ac41074fb3de |
| institution | Directory Open Access Journal |
| issn | 2211-3797 |
| language | English |
| last_indexed | 2024-03-08T12:52:23Z |
| publishDate | 2024-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Physics |
| spelling | doaj.art-6ebde103e03540ff8ac8ac41074fb3de2024-01-20T04:45:06ZengElsevierResults in Physics2211-37972024-01-0156107245Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structuresDaniel González-Iglesias0Benito Gimeno1Daniel Esperante2Pablo Martinez-Reviriego3Pablo Martín-Luna4Nuria Fuster-Martínez5César Blanch6Eduardo Martínez7Abraham Menendez8Juan Fuster9Alexej Grudiev10Instituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, Spain; Corresponding author.Instituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainInstituto de Física Corpuscular (IFIC), CSIC-UV, c/ Catedrático José Beltrán 2, 46980 Paterna, SpainCERN, European Organization for Nuclear Research, Geneva 1221, SwitzerlandThe objective of this work is the evaluation of the risk of suffering a multipactor discharge in an S-band dielectric-assist accelerating (DAA) structure for a compact low-energy linear particle accelerator dedicated to hadrontherapy treatments. A DAA structure consists of ultra-low loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure, with the advantage of having an extremely high quality factor and very high shunt impedance at room temperature, and it is therefore proposed as a potential alternative to conventional disk-loaded copper structures. However, it has been observed that these structures suffer from multipactor discharges. In fact, multipactor is one of the main problems of these devices, as it limits the maximum accelerating gradient. Because of this, the analysis of multipactor risk in the early design steps of DAA cavities is crucial to ensure the correct performance of the device after fabrication. In this paper, we present a comprehensive and detailed study of multipactor in our DAA design through numerical simulations performed with an in-house developed code based on the Monte–Carlo method. The phenomenology of the multipactor (resonant electron trajectories, electron flight time between impacts, etc.) is described in detail for different values of the accelerating gradient. It has been found that in these structures an ultra-fast non-resonant multipactor appears, which is different from the types of multipactor theoretically studied in the scientific literature. In addition, the effect of several low electron emission coatings on the multipactor threshold is investigated. Furthermore, a novel design based on the modification of the DAA cell geometry for multipactor mitigation is introduced, which shows a significant increase in the accelerating gradient handling capabilities of our prototype.http://www.sciencedirect.com/science/article/pii/S2211379723010380MultipactorDielectric accelerating structuresRF particle acceleratorsPlasma discharge |
| spellingShingle | Daniel González-Iglesias Benito Gimeno Daniel Esperante Pablo Martinez-Reviriego Pablo Martín-Luna Nuria Fuster-Martínez César Blanch Eduardo Martínez Abraham Menendez Juan Fuster Alexej Grudiev Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures Results in Physics Multipactor Dielectric accelerating structures RF particle accelerators Plasma discharge |
| title | Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures |
| title_full | Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures |
| title_fullStr | Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures |
| title_full_unstemmed | Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures |
| title_short | Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures |
| title_sort | non resonant ultra fast multipactor regime in dielectric assist accelerating structures |
| topic | Multipactor Dielectric accelerating structures RF particle accelerators Plasma discharge |
| url | http://www.sciencedirect.com/science/article/pii/S2211379723010380 |
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