Determination of the meniscus shape of a negative ion beam from an experimentally obtained beam profile
Rattachement africain : jp, it. Niveau de preuve : code pays fourni par la source.
Le résumé fourni par la source
In order to understand the physics mechanism of a negative ion extraction in negative ion sources, an emission surface of the negative ions around an aperture at a plasma grid, so-called a meniscus, has been analyzed by an inverse calculation of the negative ion trajectory in a two dimensional beam analysis code. In this method, the meniscus is defined as the final position of the negative ion trajectories which are inversely calculated from the measured beam profile to the plasma grid. In a case of the volume-produced negative ions, the calculated meniscus by the inverse calculation was similar to that obtained in conventional beam simulation codes for positive ion extractions such as BEAMORBT and SLACCAD. The negative ion current density was uniform along the meniscus. This indicates that the negative ions produced in the plasma are transported to the plasma grid uniformly as considered in the transportation of the positive ions. However, in a surface production case of negative ions, where the negative ions are generated near the plasma grid with lower work function by seeding cesium, the current density in the peripheral region of the meniscus close to the plasma grid surface was estimated to be 2 times larger than the center region, which suggested that the extraction process of the surface-produced negative ions was much different with that for the positive ions. Because this non-uniform profile of the current density made the meniscus shape strongly concave, the beam extracted from the peripheral region could have a large divergence angle, which might be one of origins of so-called beam halo. This is the first results of the determination of the meniscus based on the experiment, which is useful to improve the prediction of the meniscus shape and heat loads based on the beam trajectories including beam halo.
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Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- Determination of the meniscus shape of a negative ion beam from an experimentally obtained beam profile
- Date Crossref
- 01/01/2017
- Éditeur
- Author(s)
- Type
- proceedings-article
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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National Institutes for Quantum Science and Technology pays non établi dans la noticeStructure de recherche
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National Agency for New Technologies pays non établi dans la noticeOrganisme public
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University of Padua pays non établi dans la noticeUniversité ou école supérieure
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Istituto Nazionale di Fisica Nucleare pays non établi dans la noticeStructure de recherche
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National Institute for Quantum and Radiological Science and Technology (QST) pays non établi dans la noticeStructure de recherche
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University of Padova INFN pays non établi dans la noticeUniversité ou école supérieure
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INFN pays non établi dans la noticeInstitution
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Laboratori Nazionali di Legnaro pays non établi dans la noticeInstitution
National Institutes for Quantum Science and Technology, National Agency for New Technologies et University of Padua, avec 5 autres affiliations.
Une affiliation ne permet pas de déduire la nationalité d’un auteur.