A compact dc‐break for ECR ion source @ 18 GHZ Leonardi, O.; Torrisi, G.; Sorbello, G. ...
Microwave and optical technology letters,
December 2018, 2018-12-00, 20181201, Letnik:
60, Številka:
12
Journal Article
Recenzirano
This paper shows simulations and experimental result of a 1.5 kW waveguide DC‐Break designed for the AISHa ion source in commissioning phase at INFN‐LNS.
The DC‐Break was designed to fulfill an ...insulation of 50 kV, power losses lower than 0.5 dB by considering the compactness as key requirement.
Abstract
In the frame of the PANDORA_Gr3 project, aiming at measuring for the first time in-plasma nuclear
β
-decays of astrophysical interest, an innovative multi-diagnostic approach to correlate ...plasma parameters to nuclear activity has been proposed 1–3. This is based on several detectors and techniques (optical emission spectroscopy, RF systems, interferopolarimetry) and here we focus on high resolution spatially-resolved X-ray spectroscopy, performed by means of a X-ray pin-hole camera setup sensitive in the 0.5–20 keV energy domain. We present measurements on an Ar plasma heated by Electron Cyclotron Resonance at the ECR-plasma lab of ATOMKI-Debrecen. The achieved spatial and energy resolution were 0.5 mm and 300 eV at 8 keV, respectively 4. The new algorithm of analysis for single-photon-counted images has been developed allowing an investigation in High-Dynamic-Range (HDR) mode. Hence a spatially resolved quantitative characterization of plasma vs. plasma walls emitted spectra was done; the investigated electrons are the ones crucial for in-plasma ionization. Both stable and turbulent plasma regimes can be investigated.
Abstract
Metals can be injected into electron cyclotron resonance ion sources (ECRIS) via different techniques, among which resistive ovens are used to vaporize neutral materials, later captured by ...the energetic plasma that will step-wise ionize them, hence giving multiply charged ion beams for accelerators. Recently, PANDORA, a novel ECR plasma trap, has been conceived to perform interdisciplinary research spanning from nuclear physics to astrophysics, where in-plasma high charge states of metallic species are demanded. However, a full knowledge on the vaporization method and on the coupling of neutral atoms with plasma and its overall dynamics is still not available. Simulations, hence, are of fundamental relevance to improve the overall efficiency, reduce consumption of rare expensive isotopes, and to improve the ion source performance. We present a numerical study about metallic species suitable for oven injection in ECRIS, focusing on metals diffusion, transport, and wall deposition under molecular flow regime. We studied the metal dynamics with and without plasma. Results underline the plasma role on a space-dependent conversion yield, reflecting the strongly inhomogeneous ECR plasma. The plasma and its parameters have been modelled using an established self-consistent particle-in-cell model. The numerical tool is conceived for the PANDORA plasma trap but can be extended to other ECR plasmas and traps. As test cases we studied the
134
Cs and
48
Ca radioisotopes, as metals of interest for the modern nuclear physics. A focus is given on the
β
-decaying
134
Cs, as an application case for PANDORA, providing quantitative estimates of the γ-detection signal-poisoning effect by neutral metals deposition at the chamber wall.
Abstract
The requirements for future accelerator chains need to increase the injected beam brilliance significantly, still keeping high the beam quality in terms of reliability, reproducibility and ...stability. A roadmap for ion source development may consist of several steps: plasma simulation, multiphysics simulation of each system component, high-level control system, plasma characterization, beam characterization, data analysis and, again, plasma simulation. The cycle starts and ends with plasma simulation because it is the instrument that shows how different phenomena take part in the plasma and beam formation and because, in such a way, the accuracy grows with each cycle. Commercial multiphysics simulation tools are essential for adequately designing all ion source equipment: magnets, intense electrostatic field regions, microwave propagation and coupling, thermal dissipation and vacuum. The dependence of source performances from source parameters (magnetic field profile, gas pressure, microwave power) has been widely investigated using a high-level control system1 able to test tens of thousands of source configurations without human interaction. This characterization technique allowed us to identify a new magnetic configuration, High Stability Microwave Discharge Ion Sources2, that produces a beam with high stability, intensity and brilliance. The plasma simulation tool we developed discloses the role of two types of electrostatic waves in plasma formation and their correlation to stability. The simulation provides a complete view of ions and electrons energy and density distributions, the formation of the plasma meniscus and the beam extraction. The paper will present the results obtained with this development procedure on Microwave Discharge Ion Sources and how we started to apply it to the Electron Cyclotron Resonance Ion Sources development.
Abstract
An innovative ECR ion trap facility, called PANDORA (Plasma for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry), was designed for fundamental plasma processes and ...nuclear physics investigations. The overall structure consists of three subsystems: a) a large (70 cm in length, 28 cm in inner diameter) ECR plasma trap with a fully superconducting B-minimum magnetic system (B
max
= 3.0 T) and an innovative design to host detectors and diagnostic tools; b) an advanced non-invasive plasma multidiagnostics system to locally characterize the plasma thermodynamic properties; c) an array of 14 HPGe detectors. The PANDORA facility is conceived to measure, for the first time, in-plasma
β
-decaying isotope rates under stellar-like conditions. The experimental approach consists in a direct correlation of plasma parameters and nuclear activity by disentangling - by means of the multidiagnostic system that will work in synergy with the γ-ray array - the photons emitted by the plasma (from microwave to hard X-ray) and γ-rays emitted after the isotope
β
-decay. In addition to nuclear physics research, fundamental plasma physics studies can be conducted in this unconventional ion source equipped with tens of detection and diagnostic devices (RF polarimeter, optical emission spectroscopy (OES), X-ray imaging, space and time-resolved spectroscopy, RF probes, scope), with relevant implications for R&D of ion sources for accelerator physics and technology. Several studies have already been performed in downsized nowadays operating ECRIS. Stable and turbulent plasma regimes have been described quantitatively, studying the change of plasma morphology, confinement, and dynamics of losses using space resolved X-ray spectroscopy.
Electron cyclotron resonance ion sources (ECRIS) are the most efficient ion sources among those used in facilities for nuclear physics with stable and exotic beams, because of their ability to ...generate intense beams of medium charge state ions, or moderate intensities at high and very high state of charge (hundreds of eμA of U 33+ o Xe 34+ ). Their development has been based primarily on semi-empirical laws (High-B mode plus frequency scaling), which link the performances in terms of current and produced charge state distribution to the magnetic field (that provides the ion confinement in the plasma) and to the frequency of microwaves (used for plasma heating). A further scaling in field and frequency, to access larger extracted current and charge states, involves a considerable impact on the ion sources complexity and cost, probably exceeding the technological limits for superconducting magnets. The experience gained in the last decade produced an understanding of some new mechanisms of plasma production in ECRIS, highlighting the main weaknesses of the previous model. Additional requirements such as the improvement of stability and reliability or the minimization of beam-current ripple require a perfect knowledge of the plasma heating mechanism, to be obtained via experimental and theoretical work, accompanied by adequate plasma and beam diagnostics. We will review hereinafter the basis of the so-called "standard model" for ECRIS beam production along with the new ideas that in the coming years may disclose the path towards further improvements.
Abstract
Resistive oven technique is used to inject vapours of metallic species in electron cyclotron resonance (ECR) plasma traps, where plasma provides step-wise ionization of neutral metals, ...producing charged ion beams for accelerators. We present a numerical survey of metallic species suitable for oven injection in ECR ion sources, studying neutrals diffusion and deposition under molecular flow regime. These aspects depend on geometry of the evaporation inlet, thermodynamics, and plasma parameters, which strongly impact on ionization and charge-exchange rate, thus on the fraction of reacting neutrals. We considered diffusion of metals with and without plasma. The plasma and its parameters have been modelled considering an established self-consistent particle-in-cell model. Numerical predictions might be relevant to reduce the metal consumption, to increase the overall efficiency, and to improve the plasma ion source performances. As test case, we studied the
134
Cs isotope, as one of the alkali metals of interest for the modern nuclear physics.
In this letter, we present the design, fabrication, and characterization of a 3-D photonic crystal (PhC) waveguide based on an optimized woodpile structure operating in the millimeter-wave band. By ...carefully adjusting the size and shape of the air defect, a silicon electromagnetic bandgap (EBG) woodpile waveguide can be created: this dielectric waveguide supports a well-confined TE 10 -like mode. Numerical results for this structure have been obtained using the finite element method (FEM) simulation software Ansys HFSS and present very good agreement with the measured ones.
Abstract
A broad range of Nuclear Physics research activities have been carried out at INFN-LNS until the summer 2020, when the accelerators were stopped for the upgrade. The upgrade of LNS is a ...project mainly funded by a PON-FESR (National Program for Research and Innovation) strategic line for boosting the research infrastructures, having its own goals, time-schedule and deadlines. In addition to such an action promoted by the Italian Ministry of Research, further funds have been made available from INFN budget. The end of the phase supported by the PON for procurement and tenders is currently set for the end of 2023. A series of actions will therefore be implemented to improve scientific opportunities for users. In particular, the focus is on the commissioning of the Tandem and Superconducting Cyclotron with the new set-up, completed by the renewal of the experimental areas and the commissioning of the new fragment separator FRAISE, also financed under the PON. The high-intensity program, including the determination of the nuclear matrix elements (NME) for the double beta decay and the study of EOS for nuclear matter with large neutron content, will be made feasible by these improvements to accelerators, beamlines and detectors. Some highlights of the whole activity as well as of the Applied Physics perspectives and the Astroparticle Physics multi-messenger program, strictly connected to the Nuclear Physics program, are given.
The AISHa ion source at INFN-LNS Castro, G.; Celona, L.; Chines, F. ...
Journal of physics. Conference series,
04/2022, Letnik:
2244, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
The Advanced Ion Source for Hadrontherapy (AISHa) is an ECR ion source operating at 18 GHz, developed with the aim of producing high intensity and low emittance highly charged ion beams for ...hadrontherapy purposes. Due to its unique peculiarities, AISHa is a suitable choice for industrial and scientific applications. In the framework of the INSpIRIT and IRPT projects, in collaboration with Centro Nazionale di Adroterapia Oncologica (CNAO), new candidates for cancer treatment (including metal ion beams) are being developed. Moreover, within the IONS experiment, AISHa will be the test-bench for the development of an innovative active plasma chamber designed to increase plasma confinement by changing plasma fluxes. OES technique will be also used to refine techniques of non-invasive plasma diagnostics. Finally, a dedicated setup is under realization to provide impinging beams and detection systems for target production in nuclear physics experiments.
