Core-halo limit and internal dynamics of high intensity beams

Nghiem, P.; Valette, Matthieu; Chauvin, Nicolas; Pichoff, N.; Uriot, D.

doi:10.1063/1.4929795

Cited by 6 publications

(8 citation statements)

References 35 publications

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“…The idea is to extrapolate from the case of dense uniform core surrounded by a much more tenuous halo (see Fig. This determination has a quadruple advantage: (1) It can be applied to any type of density profile, see examples in Figure 11; (2) It corresponds well to a visual inspection of the profile; (3) It does not presuppose any relation between the halo and the general shape of the profile; (4) And, most important of all, the core and the halo so defined are located in the two different space charge field domains or, said with other words, such a limit reveals the internal dynamics of the particle beam (Nghiem et al 2014d). In this extreme case, the space charge field is clearly linear in the core and nonlinear in the halo, and the limit between core and halo is obviously the location where there is the abrupt slope variation in the profile when going from a tenuous density to a much higher one.…”

Section: Beam Characterizationmentioning

confidence: 71%

Advanced concepts and methods for very high intensity accelerators

et al. 2014

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For very high intensity accelerators, not only beam power but also space charge is a concern. Both aspects should be taken into consideration for any analysis of accelerators aiming at comparing their performances and pointing out the challenging sections. As high beam power is an issue from the lowest energy, careful and exhaustive beam loss predictions have to be done. High space charge implies lattice compactness making the implementation of beam diagnostics very problematic, so a clear strategy for beam diagnostic has to be defined. Beam halo is no longer negligible. Its dynamics is different from that of the core and plays a significant role in the particle loss process. Therefore, beam optimization must take the halo into account and beam characterization must be able to describe the halo part in addition to the core one. This paper presents the advanced concepts and methods for beam analysis, beam loss prediction, beam optimization, beam diagnostic, and beam characterization especially dedicated to very high intensity accelerators. Examples of application of these concepts are given in the case of the IFMIF accelerators.

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Section: Beam Characterizationmentioning

confidence: 71%

Advanced concepts and methods for very high intensity accelerators

et al. 2014

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“…The integrated thermal neutron flux in the cold moderator is 2.4 10 22 ´neutrons cm −2 for a year of 5MW beam operation, leading to a maximum silicon yield rate of about 0.9% per year. The cold moderator should retain more than 5% of total elongation after a year, due to silicon embrittlement.…”

Section: Neutron Heat Loadmentioning

confidence: 99%

“…There are already several mathematical definitions of the beam halo, e.g. [21,22], and even more publications on the processes in which halo is generated, e.g. [23,24].…”

Section: Timelinementioning

confidence: 99%

The European Spallation Source Design

et al. 2017

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The ESS Design: Accelerator 6The ESS Design: Target 66The ESS Design: Controls 93The ESS Design: Conventional Facilities 109Physica ScriptaPhys. Scr. 93 (2018) 014001 (121pp) https://doi.org/10. 1088/1402-4896/aa9bff This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercialNoDerivs 3.0 licence. Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercialNoDerivs 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Neutron scattering is a well-developed and extensively used means to get access to fundamental properties of biological matter as well as of physical materials. Until the end of the twentieth century that was mainly practiced with-and limited in performance by-the continuous flux of neutrons from ageing nuclear reactors (e.g. the Institut Laue-Langevin (ILL), the flagship of neutron research in Europe and in the world) [1]). Looking forward to the following two decades, an OECD report published in 1998 diagnosed the foreseeable decrease of the number of operational facilities [2] and the need to progress in performance. Considering the high scientific interest and the increasing importance of the subject for society at large, the report concluded by strongly recommending the construction of next generation neutron sources in America, Europe and Asia. Pulsed spallation neutron sources (SNS) using a proton beam power exceeding 1 MW were specifically mentioned as the most interesting high performance facilities in the future landscape of neutron laboratories.The USA was the first country to follow this advice by building the SNS in the Oak Ridge National Laboratory (ORNL) which started in 2006 [3, 4]. Japan followed in 2009 with the Japan Proton Accelerator Research Centre (J-PARC) in Tokai [5,6]. In Europe, the subject was part of a concerted effort to further develop the European world-leading largescale research infrastructures suite. In 2003, the European Strategy Forum for Research Infrastructures (ESFRI), set up by the Research Ministries of the Member States and associated countries, concluded that a 5 MW long-pulse, single target station layout with nominally 22 'public' instruments was the optimum technical reference design for an European Spallation Source (ESS) that would meet the needs of the European science community in the second quarter of the century [7].Six years later, in 2009, it materialised in a real project with the adoption of the site of Lund (Sweden). A preconstruction phase followed until the end of 2013 during which the design was finalised [8]. Construction then started with the first neutron beams planned to be available in 2019, and the ESS facility to be operational at full performance in 2025.2 Description 2.1 Principle and specifics. The high level parameters of ESS are shown in table 1. As at SNS and J-PARC, neutrons at ESS are produced by spallation, when the 2 GeV protons hit the meta...

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“…As a result, discrete phase space structures are typically measured experimentally due to the limited spatial and angular resolutions of individual devices [6]. Beams are often described in terms of their focusing characteristics, namely their core and halo components [7]. The beam core refers to the central, well-focused component, while the beam halo refers to the outer, less-focused components.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the beam core in phase space using kernel density estimation

Haba

2024

J. Phys.: Conf. Ser.

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Phase space is a mathematical construct that encompasses particle positions and their corresponding momenta. In general, discrete phase space structures are experimentally measured due to the limited spatial and angular resolutions of individual devices. From the perspective of beam focusing characteristics, beams are discussed in terms of core components and halo components. While the beam core is typically the primary component with low divergence, it may occasionally consist of multiple components with different velocity distributions. Mathematical modeling of the beam core in phase space is essential for accurately quantifying beam divergence and emittance. This paper presents a model that can be applied to beam cores with inner structures and reconstructs the phase space structure using kernel density interpolation. The reconstructed phase space structure is then utilized to determine beam divergence and emittance with greater precision. Additionally, these insights contribute to an enhanced understanding of beam physics.

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Core-halo limit and internal dynamics of high intensity beams

Cited by 6 publications

References 35 publications

Advanced concepts and methods for very high intensity accelerators

Advanced concepts and methods for very high intensity accelerators

The European Spallation Source Design

Modeling of the beam core in phase space using kernel density estimation

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