A new 18 GHz room temperature electron cyclotron resonance ion source for highly charged ion beams

Koivisto, H.; Ikonen, Arto; Kalvas, Taneli; Kosonen, Sami; Kronholm, Risto; Marttinen, M.; Tarvainen, O.; Toivanen, V.

doi:10.1063/1.5128860

Cited by 8 publications

(3 citation statements)

References 7 publications

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“…Thus, all extraction wall locations in table 3 are downstream from the magnetic field maximum at x = 86 mm. The fraction of the escaping electron flux incident on a 4×40 mm 2 extraction slit is approximately 4%, which is seemingly small but comparable to the 5% electron flux fraction incident on the extraction aperture of the JYFL 14 GHz ECRIS and exceeding the 2.5% fraction predicted for the 18 GHz HIISI ECRIS [29], both these sources performing well.…”

Section: Electron Tracking Simulationsmentioning

confidence: 62%

Design of a 10 GHz minimum-B quadrupole permanent magnet electron cyclotron resonance ion source

Kalvas¹,

Tarvainen²,

Toivanen³

et al. 2020

J. Inst.

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This paper presents a simulation study of a permanent magnet electron cyclotron resonance ion source (ECRIS) with a minimum-B quadrupole magnetic field topology. The magnetic field is made to conform to conventional ECRIS with Bmin/BECR of 0.67 and a last closed magnetic isosurface of 1.86BECR at 10 GHz. The distribution of magnetic field gradients parallel to the field, affecting the electron heating efficiency, cover a range from 0 to 13 T/m, being similar to conventional ECRIS. Therefore it is expected that the novel ion source produces warm electrons and high charge state ions in significant number. Single electron tracking simulations are used to estimate plasma flux distribution on the plasma chamber walls and to provide an estimate of the ion density profile at the extraction slit then used in ion optical simulations demonstrating high transmission through the low energy beam transport. The designed ion source is intended to study if the quadrupole field topology could produce high charge state beams in comparable intensities to conventional ECRIS and efficiently transport them through a low energy beamline, thus paving the way for a superconducting ARC-ECRIS using the same field topology. Furthermore, the prospects of the presented ion source design as an injector of a single-ended accelerator for ion beam analysis are discussed.

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Section: Electron Tracking Simulationsmentioning

confidence: 62%

Design of a 10 GHz minimum-B quadrupole permanent magnet electron cyclotron resonance ion source

Kalvas¹,

Tarvainen²,

Toivanen³

et al. 2020

J. Inst.

Self Cite

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“…A 14 N beam, produced at the Heavy-Ion Ion Source Injector ion source 65 , was accelerated to 148 MeV by the K-130 heavy-ion cyclotron. The beam impinged on a circular target foil stack mounted in the molybdenum crucible of the hot-cavity catcher.…”

Section: Methodsmentioning

confidence: 99%

Evidence of a sudden increase in the nuclear size of proton-rich silver-96

Reponen

Groote

et al. 2021

Nat Commun

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Understanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus 100Sn, where the near-equal number of protons (Z) and neutrons (N) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the N = 50 magic neutron number in the silver isotopic chain with the measurement of the charge radius of 96Ag (N = 49). The results provide a challenge for nuclear theory: calculations are unable to reproduce the pronounced discontinuity in the charge radii as one moves below N = 50. The technical advancements in this work open the N = Z region below 100Sn for further optical studies, which will lead to more comprehensive input for nuclear theory development.

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“…The source performances in terms of charge states and extracted currents has been explained by taking into account the different patterns of the electromagnetic field that is excited into the cavity, for a specific frequency (or set of frequencies) [1,2]. In order to enhance the source performances, several approaches have been used in the past years, such as the modification of the plasma cavity trying to better match the confining magnetic field profile [3], and the improvement of the microwave injection system by using modified or better cavity-matched waveguide configurations [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of Slotted Waveguide Antenna Radiating in a “Plasma-Shaped” Cavity of an ECR Ion Source

Mauro

Torrisi

Leonardi

et al. 2021

Telecom

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The design of a microwave antenna sustaining a high-energy-content plasma in Electron Cyclotron Resonance Ion Sources (ECRISs) is, under many aspects, similar to the design of a conventional antenna but presenting also peculiarities because of the antenna lying in a cavity filled by an anisotropic plasma. The plasma chamber and microwave injection system design plays a critical role in the development of future ECRISs. In this paper, we present the numerical study of an unconventionally shaped plasma cavity, in which its geometry is inspired by the typical star-shaped ECR plasma, determined by the electrons trajectories as they move under the influence of the plasma-confining magnetic field. The cavity has been designed by using CST Studio Suite with the aim to maximize the on-axis electric field, thus increasing the wave-to-plasma absorption. As a second step, an innovative microwave injection system based on side-coupled slotted waveguides is presented. This new launching scheme allows an uniform power distribution inside the plasma cavity which could lead to an increase of ion source performances in terms of charge states and extracted currents when compared to the conventional axial microwave launch scheme. Finally, the use of both the “plasma-shaped” cavity and the microwave side coupled scheme could make the overall setup more compact.

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A new 18 GHz room temperature electron cyclotron resonance ion source for highly charged ion beams

Abstract: This is a self-archived version of an original article. This version may differ from the original in pagination and typographic details.

Cited by 8 publications

References 7 publications

Design of a 10 GHz minimum-B quadrupole permanent magnet electron cyclotron resonance ion source

Design of a 10 GHz minimum-B quadrupole permanent magnet electron cyclotron resonance ion source

Evidence of a sudden increase in the nuclear size of proton-rich silver-96

Design and Analysis of Slotted Waveguide Antenna Radiating in a “Plasma-Shaped” Cavity of an ECR Ion Source

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