ECRIS2024 - List of Keywords (ECR)

Paper	Title	Other Keywords	Page
MOA3	Development towards intense uranium ion beam production of the RIKEN 28 GHz SC-ECRIS	emittance, extraction, ECRIS, ion-source	1
	G.Q. Saquilayan, J. Ohnishi, O. Kamigaito, T. Nagatomo, Y. Higurashi RIKEN Nishina Center, Wako, Japan
	High intensity Uranium ²³⁸U³⁵⁺ ion beams are produced in the 28 GHz superconducting electron cyclotron resonance ion source (SC-ECRIS) and accelerated to high energies in the Radioactive Isotope Beam Factory (RIBF) at RIKEN. We report the current progress of the SC-ECRIS. Intense beam operation of U³⁵⁺ was made possible through the development of high temperature ovens with optimized consumption rates of more than 10 mg/h and beam intensities reaching up to 250 eμA. With efforts toward realizing even higher beam intensities, it is now more important to optimize beam optics and minimize losses in the accelerator. This has stressed the study of emittance size and its growth factors. Measurement using a slit-collector type emittance monitor showed beam emittances that increase proportionally with the extraction current. For beam currents of 100 to 150 eμA, the beam emittances had minimal variation and remain at 0.15 π·mm·mrad for an extraction current of 5.5 mA. Differences between the normalized horizontal and vertical rms emittances were observed and horizontal emittances tend to be lower and less affected by beamline components. Using measured horizontal emittances coupled with a reference model calculation of space charge induced beam emittances, the ²³⁸U³⁵⁺ beam emittance ε₀ defined by the ion source was estimated. A systematic study using the calculated ε₀ to understand its correlation between the ECR parameters and magnetic field strength is currently ongoing.
	Slides MOA3 [1.637 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOA3
About •	Received ※ 15 September 2024 — Revised ※ 16 September 2024 — Accepted ※ 29 January 2025 — Issued ※ 01 March 2025
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MOB1	GANIL ion sources: optimisation for operation	ion-source, plasma, experiment, cyclotron	5
	M. Dubois, B. Osmond, F. Lemagnen, L. Gouleuf, V. Metayer GANIL, Caen, France
	The GANIL (Grand Accélérateur National d’Ions Lourds) in Caen has been producing and accelerating stable and radioactive ion beams for nuclear physics, atomic physics, radiobiology and materials irradiation since 1982. On cyclotrons facility, two ion sources (ECR4 and ECR4M) are used to produce around 4,000 hours per year of gaseous and metallic beams. Recently, studies have been carried out to find ways of optimizing beam characteristics (stability, intensities). One of these involves improving the long-term stability of the beam, which is an important parameter for tuning the accelerator and for physics experiments. At the same time, this improved stability will also reduce the need of on-call interventions for ion source experts. Other studies and tests have been carried out to increase the intensity and/or stability of the metal beams by adapting the injection of the ion source on ECR4/4M. Depending on the configuration, the gain shall be up to a factor of 2 on the charge state required for acceleration, and stability has also been improved compared to previous one. Some details and results will be presented.
	Slides MOB1 [6.158 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOB1
About •	Received ※ 04 November 2024 — Revised ※ 22 November 2024 — Accepted ※ 20 January 2025 — Issued ※ 23 January 2025
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MOB2	ECRIS operation and developments at TRIUMF	ion-source, experiment, plasma, background	10
	F. Ames, J.A. Adegun, C.R.J. Charles, K. Jayamanna, O.K. Kester, B.E. Schultz TRIUMF, Vancouver, Canada
	Rare isotope beams are used at the ISAC facility at TRIUMF for studies mainly in nuclear and astrophysics, but also for applications ranging from material science to medicine. The isotopes are produced via the ISOL technique and ionized via a set of different ion sources depending on the application. In cases where highly charged ions are needed, charge state breeding is done with a 14.5 GHz PHOENIX ECR ion source from PANTECHNIK. The source has been operational for more than a decade providing a wide range of ions from Na to U at A/Q <7 for post-acceleration. A second ECR ion source, a SUPERNANOGAN also from PANTECHNIK is used to provide highly charged ions from stable isotopes either for set-up and calibration for the rare isotope beams or for nuclear reaction studies with stable ions. The presentation will give a summary of results and will describe the challenges and improvements to the original sources. For the charge state breeding this is mainly increasing the efficiency and the purity of the delivered beams. In the case of the SUPERNANOGAN special emphasis is put on operational aspects to cover a wide range of elements and easy switchover. The latest in this series of improvements is the implementation of two frequency plasma heating in both ion sources.
	Slides MOB2 [2.008 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOB2
About •	Received ※ 15 September 2024 — Revised ※ 25 November 2024 — Accepted ※ 29 January 2025 — Issued ※ 29 March 2025
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MOC1	Recent achievements in the production of metallic ion beams with the CAPRICE ECRIS at GSI	operation, ECRIS, plasma, extraction	14
	A. Andreev, F. Maimone, J. Mäder, M. Galonska, R. Lang, R. Hollinger GSI, Darmstadt, Germany
	The GSI CAPRICE Electron Cyclotron Resonance Ion Source (ECRIS) provides highly-charged ion beams for various experiments at GSI, enabling the delivery of continuous wave (CW) metallic ion beams with low material consumption, which is crucial for producing high charge state ion beams from rare or extremely rare isotopes such as ⁴⁸Ca. These metallic beams are produced utilizing the thermal evaporation technique by resistively heated ovens. Due to the research groups’ demand for higher beam intensities, increased ion currents of higher charge states are now necessary from the CAPRICE ECRIS. A test campaign was conducted to establish and improve the production of high charge states of enriched ⁵⁴Cr and ⁵⁵Mn ion beams. During the tests, plasma images were captured using a CCD camera to support the operation and enable real-time monitoring of the material consumption. Additionally, a hot screen was used to protect the ceramic insulators in the extraction system from metal deposition, thereby improving the operational stability of the ECRIS. The application of an optical emission spectroscopy to monitor the stability of metallic ion beams during the operation with the resistively heated ovens was also investigated. This contribution presents the operational experience, the intensities and stability achieved for the aforementioned elements. In addition, an update on a recent improvement involving a specialized oven preparation stand for better conditioning of the ovens is given.
	Slides MOC1 [3.835 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOC1
About •	Received ※ 13 December 2024 — Revised ※ 21 January 2025 — Accepted ※ 29 January 2025 — Issued ※ 14 May 2025
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MOP01	Characterization of the 2.45 GHz DREEBIT ECRIS via optical spectroscopy	plasma, electron, ECRIS, ion-source	31
	M. Molodtsova, A. Philipp, E. Ritter DREEBIT, Großröhrsdorf, Germany
	ECR ion sources are widely used to provide ions for various experimental setups. DREEBIT GmbH aims to industrialize this type of ion source technology for efficient and reliable use in, e. g., hadron cancer therapy as well as ion implantation of semiconductors. Our goal is to build table-top sized ion sources which can easily be handled as part of a larger machine such as a particle accelerator or target irradiation facility, thereby fulfilling high requirements on beam current, quality, stability as well as reproducibility in serial production. To achieve this, we have already optimized the microwave injection system and magnetic plasma confinement by introducing a simple method to allow for injection of circularly polarized waves and adjusted the magnetic field distribution which led to an 80 % increase of beam current. In the present work, we show how optical emission spectroscopy was used to gain deeper information about the plasma of this specific type of ion source, independent from its ion extraction system. The plasma characterization includes studies of the electron energy distribution and the density of atomic and molecular hydrogen showing that the previous design changes of introducing circularly polarized microwaves and optimizing the magnetic field distribution have led to a well-optimized ECR ion source concerning plasma heating and proton production inside the plasma, indicating how the source performance can be enhanced in further steps.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP01
About •	Received ※ 02 October 2024 — Revised ※ 09 October 2024 — Accepted ※ 29 January 2025 — Issued ※ 07 April 2025
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MOP08	Automatic classification of plasma states in an ECR-type ion source	plasma, luminosity, network, ion-source	45
	A. Fernández-Rua, I. Arredondo, R. Justo, P. Usabiaga, J. Feuchtwanger University of the Basque Country (UPV/EHU), Leioa, Spain J. Feuchtwanger Ikerbasque, Bilbao, Spain
	In this paper we present the methodology used to acquire the data needed to obtain and train a neural network that will be used in an ECR source to infer the state of the plasma. All the data is the combination of the control signals and a set of non-intrusive measurements that can be accessed during normal operation. For this purpose, machine learning techniques are explored. First, a set of characterisation experiments are carried out in which the state of the plasma is detected for different operating conditions that are fed to a clustering algorithm. Second, a supervised learning paradigm is adopted to train a neural network that is capable of determining the state of the plasma at different working states. The variables that are controlled are: the input RF power and gas flow, the non-intrusive measurements that are acquired are: transmitted and reflected RF power and a ccd camera is used to measure the relative luminosity of the plasma. Based on these variables the state of the plasma is determined. This methodology has been applied to the low-power ECR source in which low-density hydrogen plasmas are generated at the IZPILab laboratory of the University of the Basque Country.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP08
About •	Received ※ 13 September 2024 — Revised ※ 07 February 2025 — Accepted ※ 28 February 2025 — Issued ※ 25 March 2025
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MOP09	Status report on 60 GHz ECRIS activity	experiment, ion-source, LEBT, extraction	49
	T. Andre, A. Cernuschi, C. Peaucelle, E. Labussière, M. Migliore, J. Angot, M.A. Baylac, O. Zimmermann, P. Sole, P.-O. Dumont, T. Thuillier LPSC-IN2P3, Grenoble Cedex, France F. Debray Grenoble High Magnetic Field Laboratory, Grenoble, France
	SEISM (Sixty gigahErtz Ion Source using Megawatt magnets) is an electron cyclotron resonance ion source source operating at the frequency of 60 GHz using a gyrotron producing high intensity HF pulse (up to 1 ms/300 kW/2 Hz). The prototype is based on an axial cusp magnetic geometry using polyhelix coils (installed at the LNCMI facility in Grenoble) generating a closed ECR surface at 2.1 T. Since 2019 and the restart of the project, several experimental campaigns were carried out using oxygen support gas. Beam production was studied using the setting of the source aiming to reproduce the ion current densities of 1 A/cm² previously measured. Set up and recent experimental results, will be presented. Furthermore, in the frame of the PACIFICS project (funded by French National Research Agency under the Equipex Program), a new 60 GHz ion source will be built, where polyhelix will be replaced by superconducting coils and the source will be installed at LPSC for easier availability. A new extraction system will be built in order to transform the observed high current density into a target ion beam intensity of ~100 mA. This paper will present a preliminary study of the new extraction system, built upon the principles developed by Vybin [1]. The system’s design and optimization is carried out using COMSOL Multiphysics and IBSIMU simulation tools, ensuring precise modeling of electric field fields and ion trajectories. [1] S.S. Vybin et al., “Plasma Sources Sci. Technol.”, vol. 29, p. 11LT02, 2020
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP09
About •	Received ※ 15 September 2024 — Revised ※ 22 November 2024 — Accepted ※ 02 June 2025 — Issued ※ 22 June 2025
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MOP15	Study of noble gas memory effect of ECR3 at ATLAS	ion-source, experiment, detector, ECRIS	64
	R.H. Scott, J.T. McLain, R.C. Vondrasek ANL, Lemont, Illinois, USA M. Paul, S. Bhattacharya The Hebrew University of Jerusalem, Jerusalem, Israel
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. Over the past three decades a portion of the accelerated beam time at the Argonne Tandem Linac Accelerator System (ATLAS) has been reserved for ultra-sensitive detection of argon radioisotopes. A unique noble-gas accelerator mass spectrometry (NOGAMS) technique [1] at ATLAS combines electron cyclotron resonance ion source (ECRIS) positive ion production, acceleration up to ~6 MeV/u and detection methods for separating isobars and other m/q contaminants. The ECR3 ion source was chosen for such experiments due to the limited scope of material introduced into the plasma chamber, inferring a lower background production compared to ECR2. A recent ³⁹⸴⁴²Ar NOGAMS experiment has highlighted a need to understand the beam production of material that is no longer being actively introduced into the ECRIS, known as memory effect. A quantitative study of source memory was performed to determine the decay characteristics of argon in the ECR3 ion source. Results of this study as well as details of setup and operation of ECR3 for NOGAMS experiments are presented. [1] M. Paul et al., Nucl. Instr. and Methods in Phys. Res., Sect. B, vol. 456, p. 222, 2019. doi:10.1016/j.nimb.2019.04.003
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP15
About •	Received ※ 13 September 2024 — Revised ※ 20 September 2024 — Accepted ※ 29 May 2025 — Issued ※ 07 June 2025
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TUA1	Design of a new iron plug for the TRIUMF ECRIS charge state booster	injection, plasma, booster, GUI	68
	J.A. Adegun, F. Ames, O.K. Kester TRIUMF, Vancouver, Canada
	Funding: Natural Sciences and Engineering Research Council of Canada (NSERC) and TRIUMF This paper presents an innovative solution to address the issue of asymmetric dipole fields in the injection region of the TRIUMF electron cyclotron resonance ion source charge state booster. The asymmetric fields arise from a wide gap in the booster’s injection soft iron plug, which allows the connection of the RF waveguide to the plasma chamber. Simulations have revealed that singly charged ions, injected for charge breeding, experience deflection and get lost due to the asymmetric magnetic fields instead of being effectively captured by the plasma, thereby diminishing the efficiency of the charge state booster. To rectify this problem, a novel iron plug with an enlarged inner diameter, which allows the RF waveguide to connect to the plasma chamber with no gap was designed. Furthermore, this new design necessitates alterations to the injection electrodes and plasma chamber of the booster. Additionally, the waveguide and gas-inlet windows were repositioned to ensure better RF coupling into the plasma cavity. By eliminating the gap and implementing these design changes, it is anticipated that the TRIUMF charge state booster will operate at the same overall efficiency as other PHOENIX boosters.
	Slides TUA1 [5.636 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUA1
About •	Received ※ 17 September 2024 — Revised ※ 07 October 2024 — Accepted ※ 29 May 2025 — Issued ※ 23 June 2025
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TUA2	ECR2 performance upgrades at ATLAS	plasma, ion-source, solenoid, extraction	72
	J.T. McLain, R.C. Vondrasek, R.H. Scott ANL, Lemont, Illinois, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. The user requests for higher beam energies and intensities have driven the decision to upgrade the ECR2 ion source at the Argonne Tandem Linac Accelerator System. Multiple upgrades are in progress with the expected outcome of dramatically increased ECR2 beam intensities and charge state capabilities. The magnetic upgrades include integrating an improved hexapole permanent magnet array [1] that provides the ion source radial fields, reworking the magnetic materials surrounding the plasma chamber, and installing a new cooling system for the electromagnetic solenoids that govern the ion source axial fields. The new hexapole and higher solenoid magnet operating currents will increase the ion source magnetic fields and support the use of 18 GHz RF heating, further increasing the ECR2 beam capabilities. Following these improvements and subsequent source performance, simulations of beam transport devices on the ion source platform will need to be revisited for transmission of high intensity beams. Details of these upgrade projects and simulations of the ion optics are presented. [1] R. Vondrasek, J. McLain, and R. Scott, J. Phys.: Conf. Ser., vol. 2743, p. 012044. 2024.
	Slides TUA2 [2.658 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUA2
About •	Received ※ 13 September 2024 — Revised ※ 25 November 2024 — Accepted ※ 29 January 2025 — Issued ※ 05 June 2025
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TUB1	Progress in 3D self-consistent full wave-PIC modelling of space resolved ECR plasma properties	plasma, electron, simulation, ECRIS	76
	A. Pidatella, G.S. Mauro, B. Mishra, E. Naselli, G. Torrisi, D. Mascali INFN-LNS, Catania, Italy A. Galatà, C.S. Gallo INFN-LNL, Legnaro (PD), Italy
	We present updates of a simulation suite to model in-plasma ion-electron dynamics, including self-consistent electromagnetic (EM) wave propagation and ion population kinetics to study atomic processes in ECR plasmas. The EM absorption is modelled by a heuristic collisional term in the cold dielectric tensor. However, we are stepping beyond the cold approximation, modelling the hot tensor with non-collisional RF wave damping. The tool calculates steady-state particle distributions via a full wave-PIC code and solves for collisional-radiative process giving atomic population and charge state distribution. The scheme is general and applicable to many physics’ cases of interest for the ECRIS community, including the build-up of the charge-state-distribution and the plasma emitted X-ray and optical radiation. We present its last updates and future perspectives, using as a case-study the PANDORA scenario. We report about studying in-plasma dynamics of injected metallic species and radioisotopes ionisation efficiency for different injection conditions and plasma parameters. The code is capable of reconstructing space-resolved plasma emissivity, to be directly compared to plasma emission measurements, and modelling plasma-induced modification of radioactivity.
	Slides TUB1 [21.575 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUB1
About •	Received ※ 03 October 2024 — Revised ※ 14 October 2024 — Accepted ※ 29 January 2025 — Issued ※ 01 May 2025
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TUD1	Time-resolved measurement of ion beam energy spread variation due to kinetic plasma instabilities in CW and pulsed operation of an ECRIS	plasma, ECRIS, operation, electron	86
	V. Toivanen, H.A. Koivisto University of Jyväskylä, Jyväskylä, Finland J.O. Huovila University of Eastern Finland, Joensuu, Finland O.A. Tarvainen STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The energy spread of ion beams extracted from Electron Cyclotron Resonance (ECR) ion sources is influenced by plasma conditions such as the plasma potential, and effects taking place in the beam formation region. Kinetic plasma instabilities have a significant impact on the plasma properties, and consequently on the ion beam energy spread. We present experimental results of time-resolved energy spread behaviour when kinetic plasma instabilities are present in CW and pulsed operation of the JYFL 14 GHz ECR ion source. It is shown that the instability-induced energy spread variation corresponds to a momentary plasma potential increase up to several kV from the steady-state value of 10–30 V. The method for measuring the time-resolved energy spread variation is presented, and the consequences of the energy spread and the underlying plasma potential variation for ECRIS operation are discussed.
	Slides TUD1 [3.281 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUD1
About •	Received ※ 13 September 2024 — Revised ※ 18 September 2024 — Accepted ※ 29 March 2025 — Issued ※ 09 May 2025
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TUP01	Operation with the LAPECR3 ion sources for cancer therapy accelerators	ion-source, extraction, operation, high-voltage	91
	J.Q. Li, C. Qian, J.D. Ma, L.T. Sun, X.Z. Zhang, H.W. Zhao, Y. Cao IMP/CAS, Lanzhou, People’s Republic of China H.W. Zhao UCAS, Beijing, People’s Republic of China G. Jin LANITH, Lanzhou, People’s Republic of China
	An all-permanent magnet electron cyclotron resonance ion source-LAPECR3 (Lanzhou All Permanent magnet Electron Cyclotron Resonance ion source No.3) had been developed as the C⁵⁺ ion beam injector of Heavy Ion Medical Machine (HIMM) accelerator facility since 2009 in China. The first HIMM demo facility was built in Wuwei city in 2015, which had been officially licensed to treat patients in early 2020. The facility has been proven to be very effective, and more than 1000 patients have been treated so far. In order to prevent ion source failure, each facility employs two identical LAPECR3 ion sources to supply C⁵⁺ beam. At present, there are eight HIMM facilities under construction or in operation, and more than 16 LAPECR3 ion sources have been built. In order to improve the performance of the ion source for long term operation, some techniques were employed to optimize source performance and to avoid the damage of key equipment. This paper will introduce the operation status of LAPECR ion sources at these HIMM facilities and present the latest results of carbon beam production.
	Poster TUP01 [1.475 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP01
About •	Received ※ 10 September 2024 — Revised ※ 14 September 2024 — Accepted ※ 27 May 2025 — Issued ※ 26 June 2025
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TUP05	RF and multipactor simulations in the plasma chamber of the SILHI proton source	electron, multipactoring, simulation, cavity	97
	M. Barant, A. Dubois, G. Ferrand, J. Plouin, O. Tuske CEA-IRFU, Gif-sur-Yvette, France
	In the scope of high current protons sources simulations, we tried to simulate the plasma chamber of the SILHI proton source with HFSS. This work focuses on the RF and multipactor simulation close to the boron nitride window.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP05
About •	Received ※ 09 September 2024 — Revised ※ 19 September 2024 — Accepted ※ 30 January 2025 — Issued ※ 27 February 2025
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TUP06	Wien Filter upgrade and measurement for BETSI test bench	proton, ion-source, diagnostics, electron	101
	O. Tuske, O. Delferrière, Y. Gauthier, Y. Sauce, A. Dubois CEA-IRFU, Gif-sur-Yvette, France
	During first operation of SILHI in 1995 at CEA Saclay, a velocity filter diagnostic (Wien Filter) was installed on the LEBT, analyzing the 100 mA of protons at 95 keV. The device was used many years providing beam proportion measurements on the beam axis. Unfortunately, it was damaged while handling and was no longer working as intended. This paper describes the maintenance and upgrade of the diagnostic as well as the first beam proportion figures with ALISES 2 and ALISES 3 ion sources.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP06
About •	Received ※ 13 September 2024 — Revised ※ 20 November 2024 — Accepted ※ 04 February 2025 — Issued ※ 06 June 2025
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TUP08	Planned optimization of the ion sources on the HIT test bench	ion-source, plasma, resonance, rfq	109
	T. Winkelmann, A. Peters, B. Naas, R. Cee, Th. Haberer HIT, Heidelberg, Germany
	The Heidelberg Ion Beam Therapy Center (HIT) is a hospital-based treatment facility in Germany. Since the first treatments in 2009, more than 8.500 patients have been irradiated with protons or carbon ions and since July 2021 with helium ions. At HIT, three Supernanogan ion sources supplied by Pantechnik are in operation around the clock for therapy up to 335 days a year. A 4th Supernanogan ECR ion source is installed at the HIT test bench. The test bench is currently being prepared for a measurement campaign that will begin in October. The aim of the investigations is to obtain more beam current for the carbon ions used in therapy by feeding two microwave frequencies in parallel. We expect that this experiment will provide a better understanding of the ionization process in the ion source. In the first step we will feed 14.5 GHz and an extra frequency near the resonance frequency of 14.5 GHz. ±0.5 GHz. In the second step we will feed in 14.5 GHz and 18 GHz. To characterize and evaluate the beam quality in this setup, we will use the pepperpot a 4D emittance measuring device. In addition, it is possible to measure the beam current and the beam profile at the test bench. This article provides an overview of the planned developments on the test bench.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP08
About •	Received ※ 12 September 2024 — Revised ※ 19 September 2024 — Accepted ※ 30 January 2025 — Issued ※ 14 March 2025
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TUP09	Characterization of an proton ECR ion source for low beam current	ion-source, plasma, experiment, luminosity	112
	P. Usabiaga, I. Arredondo, J. Feuchtwanger University of the Basque Country (UPV/EHU), Leioa, Spain I. Ariz, J.M. Seara Eizaguirre Fundación TEKNIKER, Ebar (Gipuzkoa), Spain J. Feuchtwanger Ikerbasque, Bilbao, Spain J. Portilla, J. Vivas, V. Etxebarria University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	Funding: Basque Government, Department of Industry, Elkartek KK-2022/00026 + Basque Government, Department of Education, IT1533-22 In this paper we analyze the behavior of a low beam current proton ECR ion source for linac. During the operation of the source, as a function of the operating parameters we have observed a complex behavior. The state of the plasma is highly dependent on the input parameters, and in some cases even bi-stable conditions can be achieved showing abrupt changes in the state. To try to understand this behavior we carried out a series of experiments varying the input parameters both sequentially and randomly to avoid following the same path every time. Thanks to these experiments we have been able to observe the change in the luminosity of the plasma, which is an indirect measure of the degree of ionization in the plasma, along with the changes in reflected and transmitted RF power delivered to the source. We also characterized the relation between the outside temperature of the ion source chamber walls and the plasma. In addition to this we have analyzed the resulting extracted ion beam using a pepperpot and a faraday cup. We have observed that our beam doesn’t have one dominant species and has three species that are found in comparable quantities.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP09
About •	Received ※ 31 August 2024 — Revised ※ 13 September 2024 — Accepted ※ 19 September 2024 — Issued ※ 29 December 2024
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TUP10	Optical diagnostic studies to analyse electron cyclotron resonance plasma produced in the GTS-LHC ion source	ion-source, experiment, plasma, dipole	116
	B.S. Bhaskar, D. Küchler CERN, Geneva, Switzerland T. Kövener Private Address, ,
	The GTS-LHC electron cyclotron resonance (ECR) ion source is an integral part of the chain of accelerators at CERN. It produces the heavy ion beams which are accelerated using a series of accelerators from LINAC up to the LHC. The ion beams are extracted from an ECR plasma generated at the GTS-LHC ion source, however, there has not yet been a non-invasive diagnostic device to study the plasma. This research focuses on the implementation of an optical diagnostics and studies the optical emission spectra (OES) as a monitor of the performance of the ion source. Furthermore, we explore the correlation between spectral properties and changing source parameters, offering insights into the behaviour of the ion source, which in turn helps in fine-tuning of the source. Specifically, the study concentrates on long-term OES analysis spanning several weeks, focusing on the production of magnesium and lead ions using the GTS-LHC ion source.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP10
About •	Received ※ 11 September 2024 — Revised ※ 19 September 2024 — Accepted ※ 09 October 2024 — Issued ※ 26 March 2025
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TUP13	Transport of intense Bismuth and Uranium beams into a radio frequency quadrupole accelerator	rfq, ion-source, extraction, focusing	124
	G.O. Rodrigues IUAC, New Delhi, India R.W. Hamm R&M Technical Enterprises, Pleasanton, CA, USA
	A 48.5 MHz RFQ has been designed to transport and accelerate ²³⁸U⁴⁰⁺ (0.52 emA) and ²⁰⁹Bi³⁰⁺ (1.047 emA) beams extracted from a high performance ECR ion source. The RFQ design comprises of a pre-buncher built into the vanes to narrow the transmitted charge state distribution as much as possible. The design parameters as a function of cell length is optimised on ²⁰⁹Bi³⁰⁺. It is shown that the losses of various ions without using an inlet aperture are inevitable, but by proper coating of the vanes of the RFQ, sputtering can be minimised to a great extent. Titanium shows better results when compared with gold or copper and this has been verified using the modelling results from SRIM. The design details of matching the ECR and the RFQ and the predicted performance will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP13
About •	Received ※ 12 March 2025 — Revised ※ 01 May 2025 — Accepted ※ 29 June 2025 — Issued ※ 29 June 2025
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TUP14	3D simulations of the CAPRICE ECRIS extraction system	simulation, experiment, plasma, extraction	131
	M.A. Händler IAP, Frankfurt am Main, Germany A. Andreev, F. Maimone, G. Franchetti, J. Mäder, M. Galonska, R. Lang, R. Hollinger GSI, Darmstadt, Germany
	The simulation of the ion extraction from the Electron Cyclotron Resonance Ion Sources (ECRISs) is necessary for the optimization and development of the performance of ion sources. Due to the magnetic field configuration of the ECRISs the calculations need to be performed in 3D. Therefore simulation programs based i.e. on C⁺⁺ libraries like IBSimu were developed. In this work a physical model was implemented in IBSimu generating detailed 3D simulations of ion extraction from a CAPRICE-type ECRIS. Simulations of multi-species Argon ion beam including Helium contribution as support gas extracted from CAPRICE are carried out. The study includes the effect of different space charge compensation degrees. Furthermore, ion beams extracted with different plasma electrode apertures were analyzed in terms of ion beam current, beam profile, beam size, divergence angle, and beam quality. In addition the simulation results were compared to experimental findings, i.e. ion beam intensities and beam profiles measured with viewing screens.
	Poster TUP14 [5.264 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP14
About •	Received ※ 20 December 2024 — Revised ※ 27 January 2025 — Accepted ※ 30 January 2025 — Issued ※ 17 April 2025
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WEA1	Characterization of D⁺ species in the 2.45 GHz ECRIS for 14-MeV neutron production	neutron, extraction, ion-source, plasma	136
	S.J. Vala, H.L. Swami, M. Abhangi, R. Kumar, R. Kumar Institute for Plasma Research, Bhat, Gandhinagar, India
	The Institute for Plasma Research has set up a 14-MeV neutron generator facility. The stability, quality, and repeatability of the D⁺ ion beam are critical parameters for ensuring the reliable operation of the neutron generator. Hence, a 2.45 GHz ECR ion source has been installed to produce the deuterium beam. The primary D beam characteristics are assessed by varying extraction voltage, microwave power, gas flow, and solenoid current of the ECRIS. By optimizing these parameters, the maximum design beam current is achieved. The D ion beam contains various species, including D⁺, D₂⁺, D₃⁺, and impurities. Accurate measurement of the D⁺ content within the D ion beam is the key parameter for a neutron generator. Multiple experiments were conducted to determine the D⁺ species and optimise the ECRIS parameters for maximum production of D⁺ species. Two beam current measurement devices, the DCCT and the Faraday Cup, were installed in the beamline to measure the total deuterium beam current and D⁺ beam current, respectively. Notably, the variation in the D⁺ fraction primarily depends on the operating parameters of the ECRIS, such as extraction voltage, microwave power and gas flow. This paper presents the results of the D⁺ ion current as a function of extraction voltage, microwave power, and gas flow rate. Understanding and characterizing the D⁺ species are essential steps toward achieving stable and efficient neutron production in fusion applications.
	Slides WEA1 [3.259 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEA1
About •	Received ※ 15 September 2024 — Revised ※ 16 September 2024 — Accepted ※ 29 January 2025 — Issued ※ 26 April 2025
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WEA2	Compact 2.45 GHz PMECR ion sources and LEBTs developed for accelerator based radiation therapy facilities at Peking University	ion-source, proton, rfq, LEBT	139
	S.X. Peng, B.J. Cui, T.H. Ma, W.B. Wu, K. Li, Y.C. Dong, Z.Y. Guo, J.E. Chen PKU, Beijing, People’s Republic of China
	Funding: National Natural Science Foundation of China (Grant Nos. 11975036, 11775007) Recently, Accelerator Based Radiation Therapy (ABRT) facilities for cancer treatment, that includes ion therapy and BNCT, have been bloomed up rapidly and is being established as a future modality to start a new era of in-hospital facilities around the world. A high current, small emittance, easy maintenance, long lifetime, high stability and reliability ion source is crucially important for those ABRT facilities. Research on this kind of characters ion source has been launched at Peking University (PKU) ion source group for more than 30 years and some exciting progresses, such as hundred mA H⁺/N+/O+ etc. beam current, less than 0.2 pi.mm.mrad emittance, a continue 300 hours non-sparking CW proton operation record have been achieved. Recently, we also involved in the ABRT campaign by in charging of ion sources. In this paper, we will summarize the several compact PKU 2.45 GHz permanent magnet ECR sources (PMECR) that were developed for proton therapy machines and BNCT facilities. The individual structure of the sources as well as the LEBT along with the commissioning results will be presented then.
	Slides WEA2 [18.981 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEA2
About •	Received ※ 18 September 2024 — Revised ※ 25 November 2024 — Accepted ※ 29 January 2025 — Issued ※ 31 May 2025
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WEB1	Mixed carbon and helium ion beams for simultaneous heavy ion radiotherapy and radiography: an ion source perspective	experiment, ion-source, plasma, instrumentation	148
	M. Galonska, A. Andreev, C. Graeff, F. Maimone, J. Mäder, L. Volz, R. Lang, R. Hollinger GSI, Darmstadt, Germany C. Graeff TU Darmstadt, Darmstadt, Germany
	Within the framework of research on simultaneous heavy ion radiotherapy and radiography, a mixed carbon/helium ion beam with a variable He percentage has been successfully established and investigated at GSI for the first time in order to study this new mode of image guidance for carbon ion beam therapy. The mixed C/He ion beam was provided by the 14.5 GHz CAPRICE ECR ion source for the subsequent linac-synchrotron accelerator systems at GSI. Prior to that experiment, different ion combinations (¹²C³⁺/⁴He⁺ or ¹²C⁴⁺/³He⁺) out of CH₄ or CO₂ have been investigated at the ECR test bench in terms of ion beam currents, stability, and C-to-He-fraction quantified by optical spectral lines and mass spectra. From an ion source perspective, it turned out that each of the different combinations comply with all the requirements of the experiments which successfully took place utilizing a ¹²C³⁺/⁴He⁺- ion beam with an energy of 225 MeV/u. Finally, both ions were simultaneously accelerated and extracted and characterised in the biophysics cave. This paper briefly outlines some of the measurements obtained at the test bench and during the beam time from an ion source perspective.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEB1
About •	Received ※ 15 January 2025 — Revised ※ 24 January 2025 — Accepted ※ 26 February 2025 — Issued ※ 22 May 2025
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WEB2	Applying machine learning techniques to the operation of the superconducting ECR ion source VENUS	operation, ion-source, controls, plasma	152
	D.S. Todd, A. Kireeff, H. Crawford, J.Y. Benitez, M. Salathe, V. Watson, Y.S. Lai LBNL, Berkeley, CA, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Nuclear Physics program under Award Numbers DE-FOA-0002490 and DE-FOA-0002875 An operator of the superconducting ECR ion source VENUS tasked with optimizing the current of a specific ion species or finding a stable operating mode is faced with an operation space composed of ten-to-twenty knobs in which to determine the next move. Machine learning techniques are well-suited to multidimensional optimization spaces. Over the last three years we have been working to employ such techniques with the VENUS ion source. We will present how the introduction of computer control has allowed us to automate tasks such as source baking or to utilize optimization tools to maximize beam currents with no human intervention. Our more recent applications of Bayesian optimization and reinforcement learning to beam current maximization and the maintenance of long term source stability will also be presented. Finally, we will discuss control and diagnostic changes that we have employed to exploit the faster data collection and decision making abilities when VENUS is under computer control.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEB2
About •	Received ※ 04 October 2024 — Revised ※ 18 October 2024 — Accepted ※ 26 February 2025 — Issued ※ 24 May 2025
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WEB3	Beam intensity prediction using ECR plasma images and machine learning	plasma, ion-source, extraction, operation	156
	Y. Morita, T. Nishi RIKEN, Saitama, Japan A. Kasagi Rikkyo University, Tokyo, Japan K. Kamakura University of Tokyo, Tokyo, Japan N. Oka National Institute of Information and Communications Technology, Tokyo, Japan
	Long-term beam stability is one of the important issues in supplying multivalent heavy ion beams using an Electron Cyclotron Resonance Ion Source (ECRIS). When the beam intensity drops for long-term operation, the ECRIS parameters need to be tuned to restore the original beam intensity. Continuous measurement of the beam intensity using a Faraday cup (FC) is impractical while the beam is in use. We have had to rely on an unreliable method of monitoring the total drain current to estimate the beam intensity during beamtime. To resolve this issue, we propose a new method for predicting the beam intensity at FC using machine learning. Our approach incorporates plasma images, captured through a hole in the beam extraction electrode, and operating parameters as input data for the machine learning model. In short-term test datasets, our model has successfully produced rough predictions of the beam intensity. This presentation will detail the prediction model and its prediction results on the test data.
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEB3
About •	Received ※ 14 September 2024 — Revised ※ 18 October 2024 — Accepted ※ 02 February 2025 — Issued ※ 04 March 2025
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THA2	Numerical design of an innovative superconducting magnetic trap for probing β-decay in ECR plasmas	plasma, injection, electron, detector	159
	G.S. Mauro, L. Celona, G. Torrisi, A. Pidatella, E. Naselli, F. Russo, B. Mishra, G. Finocchiaro, D. Santonocito, D. Mascali INFN-LNS, Catania, Italy A. Galatà INFN-LNL, Legnaro (PD), Italy
	The main aim of Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry (PANDORA) project is to build a flexible magnetic plasma trap where plasma reaches a density nₑ ∼ 10¹¹ – 10¹³ cm⁻³, and a temperature, in units of kT, kTₑ ∼ 0.1 – 30 keV in order to measure, for the first time, nuclear β-decay rates in stellar-like conditions. Here we present the numerical design of the PANDORA magnetic system, carried out by using the commercial simulators OPERA and CST Studio Suite. In particular, we discuss the design choices taken to: 1) obtain the required magnetic field levels at relevant axial and radial positions; 2) avoid the magnetic branches along the plasma chamber wall; 3) find the optimal position for the set of plasma diagnostics that will be employed. The magnetic trap has been conceived to be as large as possible, both in radial and axial directions, in order to exploit the plasma confinement mechanism on a bigger plasmoid volume. The plasma chamber will have a length of 700 mm and a diameter of 280 mm. The magnetic trap tender procedure has been completed in June 2024 and the structure realization is expected to start in late 2024.
	Slides THA2 [6.420 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-THA2
About •	Received ※ 25 January 2025 — Revised ※ 28 January 2025 — Accepted ※ 30 January 2025 — Issued ※ 15 June 2025
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Paper

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Other Keywords

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MOA3

Development towards intense uranium ion beam production of the RIKEN 28 GHz SC-ECRIS

emittance, extraction, ECRIS, ion-source

1

G.Q. Saquilayan, J. Ohnishi, O. Kamigaito, T. Nagatomo, Y. Higurashi
RIKEN Nishina Center, Wako, Japan

High intensity Uranium ²³⁸U³⁵⁺ ion beams are produced in the 28 GHz superconducting electron cyclotron resonance ion source (SC-ECRIS) and accelerated to high energies in the Radioactive Isotope Beam Factory (RIBF) at RIKEN. We report the current progress of the SC-ECRIS. Intense beam operation of U³⁵⁺ was made possible through the development of high temperature ovens with optimized consumption rates of more than 10 mg/h and beam intensities reaching up to 250 eμA. With efforts toward realizing even higher beam intensities, it is now more important to optimize beam optics and minimize losses in the accelerator. This has stressed the study of emittance size and its growth factors. Measurement using a slit-collector type emittance monitor showed beam emittances that increase proportionally with the extraction current. For beam currents of 100 to 150 eμA, the beam emittances had minimal variation and remain at 0.15 π·mm·mrad for an extraction current of 5.5 mA. Differences between the normalized horizontal and vertical rms emittances were observed and horizontal emittances tend to be lower and less affected by beamline components. Using measured horizontal emittances coupled with a reference model calculation of space charge induced beam emittances, the ²³⁸U³⁵⁺ beam emittance ε₀ defined by the ion source was estimated. A systematic study using the calculated ε₀ to understand its correlation between the ECR parameters and magnetic field strength is currently ongoing.

Slides MOA3 [1.637 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOA3

About •

Received ※ 15 September 2024 — Revised ※ 16 September 2024 — Accepted ※ 29 January 2025 — Issued ※ 01 March 2025

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MOB1

GANIL ion sources: optimisation for operation

ion-source, plasma, experiment, cyclotron

5

M. Dubois, B. Osmond, F. Lemagnen, L. Gouleuf, V. Metayer
GANIL, Caen, France

The GANIL (Grand Accélérateur National d’Ions Lourds) in Caen has been producing and accelerating stable and radioactive ion beams for nuclear physics, atomic physics, radiobiology and materials irradiation since 1982. On cyclotrons facility, two ion sources (ECR4 and ECR4M) are used to produce around 4,000 hours per year of gaseous and metallic beams. Recently, studies have been carried out to find ways of optimizing beam characteristics (stability, intensities). One of these involves improving the long-term stability of the beam, which is an important parameter for tuning the accelerator and for physics experiments. At the same time, this improved stability will also reduce the need of on-call interventions for ion source experts. Other studies and tests have been carried out to increase the intensity and/or stability of the metal beams by adapting the injection of the ion source on ECR4/4M. Depending on the configuration, the gain shall be up to a factor of 2 on the charge state required for acceleration, and stability has also been improved compared to previous one. Some details and results will be presented.

Slides MOB1 [6.158 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOB1

About •

Received ※ 04 November 2024 — Revised ※ 22 November 2024 — Accepted ※ 20 January 2025 — Issued ※ 23 January 2025

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MOB2

ECRIS operation and developments at TRIUMF

ion-source, experiment, plasma, background

10

F. Ames, J.A. Adegun, C.R.J. Charles, K. Jayamanna, O.K. Kester, B.E. Schultz
TRIUMF, Vancouver, Canada

Rare isotope beams are used at the ISAC facility at TRIUMF for studies mainly in nuclear and astrophysics, but also for applications ranging from material science to medicine. The isotopes are produced via the ISOL technique and ionized via a set of different ion sources depending on the application. In cases where highly charged ions are needed, charge state breeding is done with a 14.5 GHz PHOENIX ECR ion source from PANTECHNIK. The source has been operational for more than a decade providing a wide range of ions from Na to U at A/Q <7 for post-acceleration. A second ECR ion source, a SUPERNANOGAN also from PANTECHNIK is used to provide highly charged ions from stable isotopes either for set-up and calibration for the rare isotope beams or for nuclear reaction studies with stable ions. The presentation will give a summary of results and will describe the challenges and improvements to the original sources. For the charge state breeding this is mainly increasing the efficiency and the purity of the delivered beams. In the case of the SUPERNANOGAN special emphasis is put on operational aspects to cover a wide range of elements and easy switchover. The latest in this series of improvements is the implementation of two frequency plasma heating in both ion sources.

Slides MOB2 [2.008 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOB2

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Received ※ 15 September 2024 — Revised ※ 25 November 2024 — Accepted ※ 29 January 2025 — Issued ※ 29 March 2025

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MOC1

Recent achievements in the production of metallic ion beams with the CAPRICE ECRIS at GSI

operation, ECRIS, plasma, extraction

14

A. Andreev, F. Maimone, J. Mäder, M. Galonska, R. Lang, R. Hollinger
GSI, Darmstadt, Germany

The GSI CAPRICE Electron Cyclotron Resonance Ion Source (ECRIS) provides highly-charged ion beams for various experiments at GSI, enabling the delivery of continuous wave (CW) metallic ion beams with low material consumption, which is crucial for producing high charge state ion beams from rare or extremely rare isotopes such as ⁴⁸Ca. These metallic beams are produced utilizing the thermal evaporation technique by resistively heated ovens. Due to the research groups’ demand for higher beam intensities, increased ion currents of higher charge states are now necessary from the CAPRICE ECRIS. A test campaign was conducted to establish and improve the production of high charge states of enriched ⁵⁴Cr and ⁵⁵Mn ion beams. During the tests, plasma images were captured using a CCD camera to support the operation and enable real-time monitoring of the material consumption. Additionally, a hot screen was used to protect the ceramic insulators in the extraction system from metal deposition, thereby improving the operational stability of the ECRIS. The application of an optical emission spectroscopy to monitor the stability of metallic ion beams during the operation with the resistively heated ovens was also investigated. This contribution presents the operational experience, the intensities and stability achieved for the aforementioned elements. In addition, an update on a recent improvement involving a specialized oven preparation stand for better conditioning of the ovens is given.

Slides MOC1 [3.835 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOC1

About •

Received ※ 13 December 2024 — Revised ※ 21 January 2025 — Accepted ※ 29 January 2025 — Issued ※ 14 May 2025

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MOP01

Characterization of the 2.45 GHz DREEBIT ECRIS via optical spectroscopy

plasma, electron, ECRIS, ion-source

31

M. Molodtsova, A. Philipp, E. Ritter
DREEBIT, Großröhrsdorf, Germany

ECR ion sources are widely used to provide ions for various experimental setups. DREEBIT GmbH aims to industrialize this type of ion source technology for efficient and reliable use in, e. g., hadron cancer therapy as well as ion implantation of semiconductors. Our goal is to build table-top sized ion sources which can easily be handled as part of a larger machine such as a particle accelerator or target irradiation facility, thereby fulfilling high requirements on beam current, quality, stability as well as reproducibility in serial production. To achieve this, we have already optimized the microwave injection system and magnetic plasma confinement by introducing a simple method to allow for injection of circularly polarized waves and adjusted the magnetic field distribution which led to an 80 % increase of beam current. In the present work, we show how optical emission spectroscopy was used to gain deeper information about the plasma of this specific type of ion source, independent from its ion extraction system. The plasma characterization includes studies of the electron energy distribution and the density of atomic and molecular hydrogen showing that the previous design changes of introducing circularly polarized microwaves and optimizing the magnetic field distribution have led to a well-optimized ECR ion source concerning plasma heating and proton production inside the plasma, indicating how the source performance can be enhanced in further steps.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP01

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Received ※ 02 October 2024 — Revised ※ 09 October 2024 — Accepted ※ 29 January 2025 — Issued ※ 07 April 2025

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MOP08

Automatic classification of plasma states in an ECR-type ion source

plasma, luminosity, network, ion-source

45

A. Fernández-Rua, I. Arredondo, R. Justo, P. Usabiaga, J. Feuchtwanger
University of the Basque Country (UPV/EHU), Leioa, Spain
J. Feuchtwanger
Ikerbasque, Bilbao, Spain

In this paper we present the methodology used to acquire the data needed to obtain and train a neural network that will be used in an ECR source to infer the state of the plasma. All the data is the combination of the control signals and a set of non-intrusive measurements that can be accessed during normal operation. For this purpose, machine learning techniques are explored. First, a set of characterisation experiments are carried out in which the state of the plasma is detected for different operating conditions that are fed to a clustering algorithm. Second, a supervised learning paradigm is adopted to train a neural network that is capable of determining the state of the plasma at different working states. The variables that are controlled are: the input RF power and gas flow, the non-intrusive measurements that are acquired are: transmitted and reflected RF power and a ccd camera is used to measure the relative luminosity of the plasma. Based on these variables the state of the plasma is determined. This methodology has been applied to the low-power ECR source in which low-density hydrogen plasmas are generated at the IZPILab laboratory of the University of the Basque Country.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP08

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Received ※ 13 September 2024 — Revised ※ 07 February 2025 — Accepted ※ 28 February 2025 — Issued ※ 25 March 2025

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MOP09

Status report on 60 GHz ECRIS activity

experiment, ion-source, LEBT, extraction

49

T. Andre, A. Cernuschi, C. Peaucelle, E. Labussière, M. Migliore, J. Angot, M.A. Baylac, O. Zimmermann, P. Sole, P.-O. Dumont, T. Thuillier
LPSC-IN2P3, Grenoble Cedex, France
F. Debray
Grenoble High Magnetic Field Laboratory, Grenoble, France

SEISM (Sixty gigahErtz Ion Source using Megawatt magnets) is an electron cyclotron resonance ion source source operating at the frequency of 60 GHz using a gyrotron producing high intensity HF pulse (up to 1 ms/300 kW/2 Hz). The prototype is based on an axial cusp magnetic geometry using polyhelix coils (installed at the LNCMI facility in Grenoble) generating a closed ECR surface at 2.1 T. Since 2019 and the restart of the project, several experimental campaigns were carried out using oxygen support gas. Beam production was studied using the setting of the source aiming to reproduce the ion current densities of 1 A/cm² previously measured. Set up and recent experimental results, will be presented. Furthermore, in the frame of the PACIFICS project (funded by French National Research Agency under the Equipex Program), a new 60 GHz ion source will be built, where polyhelix will be replaced by superconducting coils and the source will be installed at LPSC for easier availability. A new extraction system will be built in order to transform the observed high current density into a target ion beam intensity of ~100 mA. This paper will present a preliminary study of the new extraction system, built upon the principles developed by Vybin [1]. The system’s design and optimization is carried out using COMSOL Multiphysics and IBSIMU simulation tools, ensuring precise modeling of electric field fields and ion trajectories.
[1] S.S. Vybin et al., “Plasma Sources Sci. Technol.”, vol. 29, p. 11LT02, 2020

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP09

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Received ※ 15 September 2024 — Revised ※ 22 November 2024 — Accepted ※ 02 June 2025 — Issued ※ 22 June 2025

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MOP15

Study of noble gas memory effect of ECR3 at ATLAS

ion-source, experiment, detector, ECRIS

64

R.H. Scott, J.T. McLain, R.C. Vondrasek
ANL, Lemont, Illinois, USA
M. Paul, S. Bhattacharya
The Hebrew University of Jerusalem, Jerusalem, Israel

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
Over the past three decades a portion of the accelerated beam time at the Argonne Tandem Linac Accelerator System (ATLAS) has been reserved for ultra-sensitive detection of argon radioisotopes. A unique noble-gas accelerator mass spectrometry (NOGAMS) technique [1] at ATLAS combines electron cyclotron resonance ion source (ECRIS) positive ion production, acceleration up to ~6 MeV/u and detection methods for separating isobars and other m/q contaminants. The ECR3 ion source was chosen for such experiments due to the limited scope of material introduced into the plasma chamber, inferring a lower background production compared to ECR2. A recent ³⁹⸴⁴²Ar NOGAMS experiment has highlighted a need to understand the beam production of material that is no longer being actively introduced into the ECRIS, known as memory effect. A quantitative study of source memory was performed to determine the decay characteristics of argon in the ECR3 ion source. Results of this study as well as details of setup and operation of ECR3 for NOGAMS experiments are presented.
[1] M. Paul et al., Nucl. Instr. and Methods in Phys. Res., Sect. B, vol. 456, p. 222, 2019. doi:10.1016/j.nimb.2019.04.003

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-MOP15

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Received ※ 13 September 2024 — Revised ※ 20 September 2024 — Accepted ※ 29 May 2025 — Issued ※ 07 June 2025

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TUA1

Design of a new iron plug for the TRIUMF ECRIS charge state booster

injection, plasma, booster, GUI

68

J.A. Adegun, F. Ames, O.K. Kester
TRIUMF, Vancouver, Canada

Funding: Natural Sciences and Engineering Research Council of Canada (NSERC) and TRIUMF
This paper presents an innovative solution to address the issue of asymmetric dipole fields in the injection region of the TRIUMF electron cyclotron resonance ion source charge state booster. The asymmetric fields arise from a wide gap in the booster’s injection soft iron plug, which allows the connection of the RF waveguide to the plasma chamber. Simulations have revealed that singly charged ions, injected for charge breeding, experience deflection and get lost due to the asymmetric magnetic fields instead of being effectively captured by the plasma, thereby diminishing the efficiency of the charge state booster. To rectify this problem, a novel iron plug with an enlarged inner diameter, which allows the RF waveguide to connect to the plasma chamber with no gap was designed. Furthermore, this new design necessitates alterations to the injection electrodes and plasma chamber of the booster. Additionally, the waveguide and gas-inlet windows were repositioned to ensure better RF coupling into the plasma cavity. By eliminating the gap and implementing these design changes, it is anticipated that the TRIUMF charge state booster will operate at the same overall efficiency as other PHOENIX boosters.

Slides TUA1 [5.636 MB]

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reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUA1

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Received ※ 17 September 2024 — Revised ※ 07 October 2024 — Accepted ※ 29 May 2025 — Issued ※ 23 June 2025

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TUA2

ECR2 performance upgrades at ATLAS

plasma, ion-source, solenoid, extraction

72

J.T. McLain, R.C. Vondrasek, R.H. Scott
ANL, Lemont, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The user requests for higher beam energies and intensities have driven the decision to upgrade the ECR2 ion source at the Argonne Tandem Linac Accelerator System. Multiple upgrades are in progress with the expected outcome of dramatically increased ECR2 beam intensities and charge state capabilities. The magnetic upgrades include integrating an improved hexapole permanent magnet array [1] that provides the ion source radial fields, reworking the magnetic materials surrounding the plasma chamber, and installing a new cooling system for the electromagnetic solenoids that govern the ion source axial fields. The new hexapole and higher solenoid magnet operating currents will increase the ion source magnetic fields and support the use of 18 GHz RF heating, further increasing the ECR2 beam capabilities. Following these improvements and subsequent source performance, simulations of beam transport devices on the ion source platform will need to be revisited for transmission of high intensity beams. Details of these upgrade projects and simulations of the ion optics are presented.
[1] R. Vondrasek, J. McLain, and R. Scott, J. Phys.: Conf. Ser., vol. 2743, p. 012044. 2024.

Slides TUA2 [2.658 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUA2

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Received ※ 13 September 2024 — Revised ※ 25 November 2024 — Accepted ※ 29 January 2025 — Issued ※ 05 June 2025

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TUB1

Progress in 3D self-consistent full wave-PIC modelling of space resolved ECR plasma properties

plasma, electron, simulation, ECRIS

76

A. Pidatella, G.S. Mauro, B. Mishra, E. Naselli, G. Torrisi, D. Mascali
INFN-LNS, Catania, Italy
A. Galatà, C.S. Gallo
INFN-LNL, Legnaro (PD), Italy

We present updates of a simulation suite to model in-plasma ion-electron dynamics, including self-consistent electromagnetic (EM) wave propagation and ion population kinetics to study atomic processes in ECR plasmas. The EM absorption is modelled by a heuristic collisional term in the cold dielectric tensor. However, we are stepping beyond the cold approximation, modelling the hot tensor with non-collisional RF wave damping. The tool calculates steady-state particle distributions via a full wave-PIC code and solves for collisional-radiative process giving atomic population and charge state distribution. The scheme is general and applicable to many physics’ cases of interest for the ECRIS community, including the build-up of the charge-state-distribution and the plasma emitted X-ray and optical radiation. We present its last updates and future perspectives, using as a case-study the PANDORA scenario. We report about studying in-plasma dynamics of injected metallic species and radioisotopes ionisation efficiency for different injection conditions and plasma parameters. The code is capable of reconstructing space-resolved plasma emissivity, to be directly compared to plasma emission measurements, and modelling plasma-induced modification of radioactivity.

Slides TUB1 [21.575 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUB1

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Received ※ 03 October 2024 — Revised ※ 14 October 2024 — Accepted ※ 29 January 2025 — Issued ※ 01 May 2025

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TUD1

Time-resolved measurement of ion beam energy spread variation due to kinetic plasma instabilities in CW and pulsed operation of an ECRIS

plasma, ECRIS, operation, electron

86

V. Toivanen, H.A. Koivisto
University of Jyväskylä, Jyväskylä, Finland
J.O. Huovila
University of Eastern Finland, Joensuu, Finland
O.A. Tarvainen
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The energy spread of ion beams extracted from Electron Cyclotron Resonance (ECR) ion sources is influenced by plasma conditions such as the plasma potential, and effects taking place in the beam formation region. Kinetic plasma instabilities have a significant impact on the plasma properties, and consequently on the ion beam energy spread. We present experimental results of time-resolved energy spread behaviour when kinetic plasma instabilities are present in CW and pulsed operation of the JYFL 14 GHz ECR ion source. It is shown that the instability-induced energy spread variation corresponds to a momentary plasma potential increase up to several kV from the steady-state value of 10–30 V. The method for measuring the time-resolved energy spread variation is presented, and the consequences of the energy spread and the underlying plasma potential variation for ECRIS operation are discussed.

Slides TUD1 [3.281 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUD1

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Received ※ 13 September 2024 — Revised ※ 18 September 2024 — Accepted ※ 29 March 2025 — Issued ※ 09 May 2025

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TUP01

Operation with the LAPECR3 ion sources for cancer therapy accelerators

ion-source, extraction, operation, high-voltage

91

J.Q. Li, C. Qian, J.D. Ma, L.T. Sun, X.Z. Zhang, H.W. Zhao, Y. Cao
IMP/CAS, Lanzhou, People’s Republic of China
H.W. Zhao
UCAS, Beijing, People’s Republic of China
G. Jin
LANITH, Lanzhou, People’s Republic of China

An all-permanent magnet electron cyclotron resonance ion source-LAPECR3 (Lanzhou All Permanent magnet Electron Cyclotron Resonance ion source No.3) had been developed as the C⁵⁺ ion beam injector of Heavy Ion Medical Machine (HIMM) accelerator facility since 2009 in China. The first HIMM demo facility was built in Wuwei city in 2015, which had been officially licensed to treat patients in early 2020. The facility has been proven to be very effective, and more than 1000 patients have been treated so far. In order to prevent ion source failure, each facility employs two identical LAPECR3 ion sources to supply C⁵⁺ beam. At present, there are eight HIMM facilities under construction or in operation, and more than 16 LAPECR3 ion sources have been built. In order to improve the performance of the ion source for long term operation, some techniques were employed to optimize source performance and to avoid the damage of key equipment. This paper will introduce the operation status of LAPECR ion sources at these HIMM facilities and present the latest results of carbon beam production.

Poster TUP01 [1.475 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP01

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Received ※ 10 September 2024 — Revised ※ 14 September 2024 — Accepted ※ 27 May 2025 — Issued ※ 26 June 2025

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TUP05

RF and multipactor simulations in the plasma chamber of the SILHI proton source

electron, multipactoring, simulation, cavity

97

M. Barant, A. Dubois, G. Ferrand, J. Plouin, O. Tuske
CEA-IRFU, Gif-sur-Yvette, France

In the scope of high current protons sources simulations, we tried to simulate the plasma chamber of the SILHI proton source with HFSS. This work focuses on the RF and multipactor simulation close to the boron nitride window.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP05

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Received ※ 09 September 2024 — Revised ※ 19 September 2024 — Accepted ※ 30 January 2025 — Issued ※ 27 February 2025

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TUP06

Wien Filter upgrade and measurement for BETSI test bench

proton, ion-source, diagnostics, electron

101

O. Tuske, O. Delferrière, Y. Gauthier, Y. Sauce, A. Dubois
CEA-IRFU, Gif-sur-Yvette, France

During first operation of SILHI in 1995 at CEA Saclay, a velocity filter diagnostic (Wien Filter) was installed on the LEBT, analyzing the 100 mA of protons at 95 keV. The device was used many years providing beam proportion measurements on the beam axis. Unfortunately, it was damaged while handling and was no longer working as intended. This paper describes the maintenance and upgrade of the diagnostic as well as the first beam proportion figures with ALISES 2 and ALISES 3 ion sources.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP06

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Received ※ 13 September 2024 — Revised ※ 20 November 2024 — Accepted ※ 04 February 2025 — Issued ※ 06 June 2025

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TUP08

Planned optimization of the ion sources on the HIT test bench

ion-source, plasma, resonance, rfq

109

T. Winkelmann, A. Peters, B. Naas, R. Cee, Th. Haberer
HIT, Heidelberg, Germany

The Heidelberg Ion Beam Therapy Center (HIT) is a hospital-based treatment facility in Germany. Since the first treatments in 2009, more than 8.500 patients have been irradiated with protons or carbon ions and since July 2021 with helium ions. At HIT, three Supernanogan ion sources supplied by Pantechnik are in operation around the clock for therapy up to 335 days a year. A 4th Supernanogan ECR ion source is installed at the HIT test bench. The test bench is currently being prepared for a measurement campaign that will begin in October. The aim of the investigations is to obtain more beam current for the carbon ions used in therapy by feeding two microwave frequencies in parallel. We expect that this experiment will provide a better understanding of the ionization process in the ion source. In the first step we will feed 14.5 GHz and an extra frequency near the resonance frequency of 14.5 GHz. ±0.5 GHz. In the second step we will feed in 14.5 GHz and 18 GHz. To characterize and evaluate the beam quality in this setup, we will use the pepperpot a 4D emittance measuring device. In addition, it is possible to measure the beam current and the beam profile at the test bench. This article provides an overview of the planned developments on the test bench.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP08

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Received ※ 12 September 2024 — Revised ※ 19 September 2024 — Accepted ※ 30 January 2025 — Issued ※ 14 March 2025

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TUP09

Characterization of an proton ECR ion source for low beam current

ion-source, plasma, experiment, luminosity

112

P. Usabiaga, I. Arredondo, J. Feuchtwanger
University of the Basque Country (UPV/EHU), Leioa, Spain
I. Ariz, J.M. Seara Eizaguirre
Fundación TEKNIKER, Ebar (Gipuzkoa), Spain
J. Feuchtwanger
Ikerbasque, Bilbao, Spain
J. Portilla, J. Vivas, V. Etxebarria
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

Funding: Basque Government, Department of Industry, Elkartek KK-2022/00026 + Basque Government, Department of Education, IT1533-22
In this paper we analyze the behavior of a low beam current proton ECR ion source for linac. During the operation of the source, as a function of the operating parameters we have observed a complex behavior. The state of the plasma is highly dependent on the input parameters, and in some cases even bi-stable conditions can be achieved showing abrupt changes in the state. To try to understand this behavior we carried out a series of experiments varying the input parameters both sequentially and randomly to avoid following the same path every time. Thanks to these experiments we have been able to observe the change in the luminosity of the plasma, which is an indirect measure of the degree of ionization in the plasma, along with the changes in reflected and transmitted RF power delivered to the source. We also characterized the relation between the outside temperature of the ion source chamber walls and the plasma. In addition to this we have analyzed the resulting extracted ion beam using a pepperpot and a faraday cup. We have observed that our beam doesn’t have one dominant species and has three species that are found in comparable quantities.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP09

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Received ※ 31 August 2024 — Revised ※ 13 September 2024 — Accepted ※ 19 September 2024 — Issued ※ 29 December 2024

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TUP10

Optical diagnostic studies to analyse electron cyclotron resonance plasma produced in the GTS-LHC ion source

ion-source, experiment, plasma, dipole

116

B.S. Bhaskar, D. Küchler
CERN, Geneva, Switzerland
T. Kövener
Private Address, ,

The GTS-LHC electron cyclotron resonance (ECR) ion source is an integral part of the chain of accelerators at CERN. It produces the heavy ion beams which are accelerated using a series of accelerators from LINAC up to the LHC. The ion beams are extracted from an ECR plasma generated at the GTS-LHC ion source, however, there has not yet been a non-invasive diagnostic device to study the plasma. This research focuses on the implementation of an optical diagnostics and studies the optical emission spectra (OES) as a monitor of the performance of the ion source. Furthermore, we explore the correlation between spectral properties and changing source parameters, offering insights into the behaviour of the ion source, which in turn helps in fine-tuning of the source. Specifically, the study concentrates on long-term OES analysis spanning several weeks, focusing on the production of magnesium and lead ions using the GTS-LHC ion source.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP10

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Received ※ 11 September 2024 — Revised ※ 19 September 2024 — Accepted ※ 09 October 2024 — Issued ※ 26 March 2025

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TUP13

Transport of intense Bismuth and Uranium beams into a radio frequency quadrupole accelerator

rfq, ion-source, extraction, focusing

124

G.O. Rodrigues
IUAC, New Delhi, India
R.W. Hamm
R&M Technical Enterprises, Pleasanton, CA, USA

A 48.5 MHz RFQ has been designed to transport and accelerate ²³⁸U⁴⁰⁺ (0.52 emA) and ²⁰⁹Bi³⁰⁺ (1.047 emA) beams extracted from a high performance ECR ion source. The RFQ design comprises of a pre-buncher built into the vanes to narrow the transmitted charge state distribution as much as possible. The design parameters as a function of cell length is optimised on ²⁰⁹Bi³⁰⁺. It is shown that the losses of various ions without using an inlet aperture are inevitable, but by proper coating of the vanes of the RFQ, sputtering can be minimised to a great extent. Titanium shows better results when compared with gold or copper and this has been verified using the modelling results from SRIM. The design details of matching the ECR and the RFQ and the predicted performance will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP13

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Received ※ 12 March 2025 — Revised ※ 01 May 2025 — Accepted ※ 29 June 2025 — Issued ※ 29 June 2025

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TUP14

3D simulations of the CAPRICE ECRIS extraction system

simulation, experiment, plasma, extraction

131

M.A. Händler
IAP, Frankfurt am Main, Germany
A. Andreev, F. Maimone, G. Franchetti, J. Mäder, M. Galonska, R. Lang, R. Hollinger
GSI, Darmstadt, Germany

The simulation of the ion extraction from the Electron Cyclotron Resonance Ion Sources (ECRISs) is necessary for the optimization and development of the performance of ion sources. Due to the magnetic field configuration of the ECRISs the calculations need to be performed in 3D. Therefore simulation programs based i.e. on C⁺⁺ libraries like IBSimu were developed. In this work a physical model was implemented in IBSimu generating detailed 3D simulations of ion extraction from a CAPRICE-type ECRIS. Simulations of multi-species Argon ion beam including Helium contribution as support gas extracted from CAPRICE are carried out. The study includes the effect of different space charge compensation degrees. Furthermore, ion beams extracted with different plasma electrode apertures were analyzed in terms of ion beam current, beam profile, beam size, divergence angle, and beam quality. In addition the simulation results were compared to experimental findings, i.e. ion beam intensities and beam profiles measured with viewing screens.

Poster TUP14 [5.264 MB]

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reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-TUP14

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Received ※ 20 December 2024 — Revised ※ 27 January 2025 — Accepted ※ 30 January 2025 — Issued ※ 17 April 2025

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WEA1

Characterization of D⁺ species in the 2.45 GHz ECRIS for 14-MeV neutron production

neutron, extraction, ion-source, plasma

136

S.J. Vala, H.L. Swami, M. Abhangi, R. Kumar, R. Kumar
Institute for Plasma Research, Bhat, Gandhinagar, India

The Institute for Plasma Research has set up a 14-MeV neutron generator facility. The stability, quality, and repeatability of the D⁺ ion beam are critical parameters for ensuring the reliable operation of the neutron generator. Hence, a 2.45 GHz ECR ion source has been installed to produce the deuterium beam. The primary D beam characteristics are assessed by varying extraction voltage, microwave power, gas flow, and solenoid current of the ECRIS. By optimizing these parameters, the maximum design beam current is achieved. The D ion beam contains various species, including D⁺, D₂⁺, D₃⁺, and impurities. Accurate measurement of the D⁺ content within the D ion beam is the key parameter for a neutron generator. Multiple experiments were conducted to determine the D⁺ species and optimise the ECRIS parameters for maximum production of D⁺ species. Two beam current measurement devices, the DCCT and the Faraday Cup, were installed in the beamline to measure the total deuterium beam current and D⁺ beam current, respectively. Notably, the variation in the D⁺ fraction primarily depends on the operating parameters of the ECRIS, such as extraction voltage, microwave power and gas flow. This paper presents the results of the D⁺ ion current as a function of extraction voltage, microwave power, and gas flow rate. Understanding and characterizing the D⁺ species are essential steps toward achieving stable and efficient neutron production in fusion applications.

Slides WEA1 [3.259 MB]

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reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEA1

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Received ※ 15 September 2024 — Revised ※ 16 September 2024 — Accepted ※ 29 January 2025 — Issued ※ 26 April 2025

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WEA2

Compact 2.45 GHz PMECR ion sources and LEBTs developed for accelerator based radiation therapy facilities at Peking University

ion-source, proton, rfq, LEBT

139

S.X. Peng, B.J. Cui, T.H. Ma, W.B. Wu, K. Li, Y.C. Dong, Z.Y. Guo, J.E. Chen
PKU, Beijing, People’s Republic of China

Funding: National Natural Science Foundation of China (Grant Nos. 11975036, 11775007)
Recently, Accelerator Based Radiation Therapy (ABRT) facilities for cancer treatment, that includes ion therapy and BNCT, have been bloomed up rapidly and is being established as a future modality to start a new era of in-hospital facilities around the world. A high current, small emittance, easy maintenance, long lifetime, high stability and reliability ion source is crucially important for those ABRT facilities. Research on this kind of characters ion source has been launched at Peking University (PKU) ion source group for more than 30 years and some exciting progresses, such as hundred mA H⁺/N+/O+ etc. beam current, less than 0.2 pi.mm.mrad emittance, a continue 300 hours non-sparking CW proton operation record have been achieved. Recently, we also involved in the ABRT campaign by in charging of ion sources. In this paper, we will summarize the several compact PKU 2.45 GHz permanent magnet ECR sources (PMECR) that were developed for proton therapy machines and BNCT facilities. The individual structure of the sources as well as the LEBT along with the commissioning results will be presented then.

Slides WEA2 [18.981 MB]

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reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEA2

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Received ※ 18 September 2024 — Revised ※ 25 November 2024 — Accepted ※ 29 January 2025 — Issued ※ 31 May 2025

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WEB1

Mixed carbon and helium ion beams for simultaneous heavy ion radiotherapy and radiography: an ion source perspective

experiment, ion-source, plasma, instrumentation

148

M. Galonska, A. Andreev, C. Graeff, F. Maimone, J. Mäder, L. Volz, R. Lang, R. Hollinger
GSI, Darmstadt, Germany
C. Graeff
TU Darmstadt, Darmstadt, Germany

Within the framework of research on simultaneous heavy ion radiotherapy and radiography, a mixed carbon/helium ion beam with a variable He percentage has been successfully established and investigated at GSI for the first time in order to study this new mode of image guidance for carbon ion beam therapy. The mixed C/He ion beam was provided by the 14.5 GHz CAPRICE ECR ion source for the subsequent linac-synchrotron accelerator systems at GSI. Prior to that experiment, different ion combinations (¹²C³⁺/⁴He⁺ or ¹²C⁴⁺/³He⁺) out of CH₄ or CO₂ have been investigated at the ECR test bench in terms of ion beam currents, stability, and C-to-He-fraction quantified by optical spectral lines and mass spectra. From an ion source perspective, it turned out that each of the different combinations comply with all the requirements of the experiments which successfully took place utilizing a ¹²C³⁺/⁴He⁺- ion beam with an energy of 225 MeV/u. Finally, both ions were simultaneously accelerated and extracted and characterised in the biophysics cave. This paper briefly outlines some of the measurements obtained at the test bench and during the beam time from an ion source perspective.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEB1

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Received ※ 15 January 2025 — Revised ※ 24 January 2025 — Accepted ※ 26 February 2025 — Issued ※ 22 May 2025

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WEB2

Applying machine learning techniques to the operation of the superconducting ECR ion source VENUS

operation, ion-source, controls, plasma

152

D.S. Todd, A. Kireeff, H. Crawford, J.Y. Benitez, M. Salathe, V. Watson, Y.S. Lai
LBNL, Berkeley, CA, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Nuclear Physics program under Award Numbers DE-FOA-0002490 and DE-FOA-0002875
An operator of the superconducting ECR ion source VENUS tasked with optimizing the current of a specific ion species or finding a stable operating mode is faced with an operation space composed of ten-to-twenty knobs in which to determine the next move. Machine learning techniques are well-suited to multidimensional optimization spaces. Over the last three years we have been working to employ such techniques with the VENUS ion source. We will present how the introduction of computer control has allowed us to automate tasks such as source baking or to utilize optimization tools to maximize beam currents with no human intervention. Our more recent applications of Bayesian optimization and reinforcement learning to beam current maximization and the maintenance of long term source stability will also be presented. Finally, we will discuss control and diagnostic changes that we have employed to exploit the faster data collection and decision making abilities when VENUS is under computer control.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEB2

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Received ※ 04 October 2024 — Revised ※ 18 October 2024 — Accepted ※ 26 February 2025 — Issued ※ 24 May 2025

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WEB3

Beam intensity prediction using ECR plasma images and machine learning

plasma, ion-source, extraction, operation

156

Y. Morita, T. Nishi
RIKEN, Saitama, Japan
A. Kasagi
Rikkyo University, Tokyo, Japan
K. Kamakura
University of Tokyo, Tokyo, Japan
N. Oka
National Institute of Information and Communications Technology, Tokyo, Japan

Long-term beam stability is one of the important issues in supplying multivalent heavy ion beams using an Electron Cyclotron Resonance Ion Source (ECRIS). When the beam intensity drops for long-term operation, the ECRIS parameters need to be tuned to restore the original beam intensity. Continuous measurement of the beam intensity using a Faraday cup (FC) is impractical while the beam is in use. We have had to rely on an unreliable method of monitoring the total drain current to estimate the beam intensity during beamtime. To resolve this issue, we propose a new method for predicting the beam intensity at FC using machine learning. Our approach incorporates plasma images, captured through a hole in the beam extraction electrode, and operating parameters as input data for the machine learning model. In short-term test datasets, our model has successfully produced rough predictions of the beam intensity. This presentation will detail the prediction model and its prediction results on the test data.

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-WEB3

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Received ※ 14 September 2024 — Revised ※ 18 October 2024 — Accepted ※ 02 February 2025 — Issued ※ 04 March 2025

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THA2

Numerical design of an innovative superconducting magnetic trap for probing β-decay in ECR plasmas

plasma, injection, electron, detector

159

G.S. Mauro, L. Celona, G. Torrisi, A. Pidatella, E. Naselli, F. Russo, B. Mishra, G. Finocchiaro, D. Santonocito, D. Mascali
INFN-LNS, Catania, Italy
A. Galatà
INFN-LNL, Legnaro (PD), Italy

The main aim of Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry (PANDORA) project is to build a flexible magnetic plasma trap where plasma reaches a density nₑ ∼ 10¹¹ – 10¹³ cm⁻³, and a temperature, in units of kT, kTₑ ∼ 0.1 – 30 keV in order to measure, for the first time, nuclear β-decay rates in stellar-like conditions. Here we present the numerical design of the PANDORA magnetic system, carried out by using the commercial simulators OPERA and CST Studio Suite. In particular, we discuss the design choices taken to: 1) obtain the required magnetic field levels at relevant axial and radial positions; 2) avoid the magnetic branches along the plasma chamber wall; 3) find the optimal position for the set of plasma diagnostics that will be employed. The magnetic trap has been conceived to be as large as possible, both in radial and axial directions, in order to exploit the plasma confinement mechanism on a bigger plasmoid volume. The plasma chamber will have a length of 700 mm and a diameter of 280 mm. The magnetic trap tender procedure has been completed in June 2024 and the structure realization is expected to start in late 2024.

Slides THA2 [6.420 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-ECRIS2024-THA2

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Received ※ 25 January 2025 — Revised ※ 28 January 2025 — Accepted ※ 30 January 2025 — Issued ※ 15 June 2025

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