24thInternationalWorkshop onECRIonSources(ECRIS’20) ·...

24th International Workshopon ECR Ion Sources (ECRIS’20)

Monday 28 September 2020 - Wednesday 30 September 2020

Book of Abstracts

Contents

FECR Ion Source Development and Challenges . . . . . . . . . . . . . . . . . . . . . . . . 1

LECR5 Development and Status Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Status of the AISHa Ion Source at INFN-LNS . . . . . . . . . . . . . . . . . . . . . . . . . 2

Gismo Gasdynamic ECR Ion Source Status: Towards High-Intensity Ion Beams of SuperiorQuality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Status of the 45 GHz MARS-D Ion Source . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Conceptual Design of Heavy Ion ToF-ERDA Facility Based on Permanent Magnet ECRISand Variable Frequency RFQ Accelerator . . . . . . . . . . . . . . . . . . . . . . . . . 3

FRIB 28 GHz ECR Ion Source Development and Status . . . . . . . . . . . . . . . . . . . 4

Imaging in X-ray Ranges to Locally Investigate the Effect of the Two- Close-FrequencyHeating in ECRIS Plasmas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

High Resolution X-ray Imaging as a Powerful Diagnostics Tool to Investigate ECRIS PlasmaStructure and Confinement Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . 5

The Relationship Between the Diffusion of Hot Electrons, Plasma Stability, and ECR IonSource Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Production of 48Ca and 48Ti Ion Beams at the DC-280 Cyclotron . . . . . . . . . . . . . 6

ECR Discharge in Solenoidal Magnetic Field as a Source of Dense Wide- Aperture PlasmaFluxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Stable and Intense 48Ca Ion Beam Production With a Microwave Shielded Oven and anOptical Spectrometer as Diagnostic Tool . . . . . . . . . . . . . . . . . . . . . . . . . 7

New Metallic Stable Ion Beams for GANIL . . . . . . . . . . . . . . . . . . . . . . . . . . 7

A New Resistive High Temperature Oven for Metallic Beams Production . . . . . . . . . 8

Microcontrollers as Gate and Delay Generators for Time Resolved Measurements . . . . 8

Plasma Parameters at Upper/down StreamRegionNear Ecr Zone andOptimizingMicrowave-Launching on ECRIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Tentative Solution to Plasma Chamber Cooling for High Power ECR Ion Source Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

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Development of HTO with Inductive Technology for Uranium Beam Production . . . . . 10

Influences of Magnetic Field Parameters to ECRIS Plasma Characteristics . . . . . . . . . 11

A Theoretical Model of High-Bmin Instabilities and Experimental Tests of Its Predictions 11

Experimental Evidence of Trapped Waves in a Simple Mirror Magnetic-Trap . . . . . . . 12

Simulation and Experimental Investigation of an Ion Source Metallic Oven . . . . . . . . 12

Progress in Self-Consistent Modeling of Time- and Space-Dependent Phenomena in EcrisPlasma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

A Guiding Centre Approximation Approach for the Simulation of Electron Trajectories inECR and Microwave Ion Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Electromagnetic Simulation of ’plasma-shaped’ Plasma Chamber for Innovative ECRIS . 14

Characterization of 2.45 GHz ECR Ion Source Bench for Accelerator-Based 14-MeVNeutronGenerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Electron Cyclotron Resonance Ion Source Related Research and Development Work at theDepartment of Physics, University of Jyväskylä (JYFL) . . . . . . . . . . . . . . . . . 15

Study on the Correlation between Energy Distribution of Electrons Lost from the Confine-ment and Plasma Bremsstrahlung on a min-B ECR Plasmas . . . . . . . . . . . . . . 16

Ultra-High Current Density Produced by a 60 Ghz Ecr Ion Source . . . . . . . . . . . . . 17

Multi-Species Child-Langmuir Law with Application to ECR Ion Sources . . . . . . . . . 17

Beams with Three-Fold Rotational Symmetry: A Theoretical Study . . . . . . . . . . . . 18

Improvement of the Cryostat System Performance of 28-Ghz Electron Cyclotron ResonanceIon Source of the Biba by a Radiation Shielding . . . . . . . . . . . . . . . . . . . . . 18

Precise Identification of Extracted Ion Beam Spectrum Initially Obtained in SynthesizingIron-Endohedral Fullerenes on ECRIS . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

High Intensity Vanadium-Ion Beam Production to Search for New Super- Heavy Elementwith Z = 119 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Enhancing Production of Multicharged Ions by Pulse Modulated Microwaves under Low ZGas Mixing Operation on ECRIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Beam Profile Measurements of Decelerated Multicharged Xe Ions from ECRIS for Estimat-ing Low Energy Damage on Satellites Components . . . . . . . . . . . . . . . . . . . 20

Observation of Cyclotron Instabilities in SECRAL-II Ion Source . . . . . . . . . . . . . . 21

High Intensity Ion Beam Extraction System for FECR . . . . . . . . . . . . . . . . . . . . 21

39Ar Enrichment System Based on a 2.45 GHz ECR Ion Source . . . . . . . . . . . . . . . 22

Conceptual Design of an Electrostatic Trap for High Intensity Pulsed Beam . . . . . . . 22

Numerical Simulations of Plasma Dynamics in ECRIS Afterglow . . . . . . . . . . . . . . 23

Production of Metal Ion Beams From ECR Ion Sources . . . . . . . . . . . . . . . . . . . 23

Present Status of HIMAC ECR Ion Sources . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Attempt to Develop a 2.45 GHz Microwave Driven Source for Plasma Flood Gun . . . . . 25

Role of the 1+ Beam Optics Upstream the SPIRAL1 Charge Breeder . . . . . . . . . . . . 25

LNL GANIL LPSC Collaboration OnThe Contaminants Reduction In ECR Charge Breeders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

ECR3 Commissioning and Planning for C-14 Ion Beams at the Argonne Tandem LinacAccelerator System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Improvement of the Efficiency of the Triumf Charge State Booster . . . . . . . . . . . . . 27

Studies of ECR Plasma Chamber Contamination With Accelerated Beams and DiamondDetectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Opening Session . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Status Report and New Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Status Report and New Development II . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Plasma Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Poster/ Short Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Open Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Adjourn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Announcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Plasma Physics and Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Plasma Physics and Techniques II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Plasma Physics and Techniques II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Modelisation, Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Poster/ Short Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Electron Cyclotron Emission Imaging of Electron Cyclotron Resonance Ion Source Plasmas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

24th International Workshop on ECR Ion Sources (ECRIS’20) / Book of Abstracts

11

FECR Ion Source Development and Challenges

Liangting Sun1 ; Libin LiNone ; Lixuan LiNone ; Wang LuNone ; Enmin MeiNone ; Xianjin OuNone ; Xudong WangNone; Beimin WuNone ; Wei WuNone ; Xuezhen ZhangNone ; Hongwei ZhaoNone ; Shijun ZhengNone ; Li ZhuNone ; ZhenShenNone ; Yuquan ChenNone ; Mingzhi GuanNone ; Jibo LiNone

1 Institute of Modern Physics, CAS

Corresponding Author(s): [email protected]

FECR or the First 4th generation ECR ion source isunder development at Institute of Modern Physics(IMP) since 2015. This ion source is aiming to extractintense highly charged heavy ion beams in the orderof emA from the dense plasma heated with 45 GHzmicrowave power. To provide effective magneticconfinement to the 45 GHz ECR plasma, a state ofthe art Nb3Sn magnet with min-B configuration is astraightforward technical path. As there is no muchprecedent references, it has to be designed,prototyped at IMP through in-house development.Meanwhile, other physics and technical challenges toa 4th generation ECR ion source are also tackled atIMP to find feasible solutions. This paper will give abrief review of the critical issues in the developmentof FECR ion source. A detailed report on the status ofFECR prototype magnet development will bepresented.

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LECR5 Development and Status ReportCheng Qian1 ; Jingrui AnNone ; Jianjun ChangNone ; Xing FangNone ; Yucheng FengNone ; Junwei GuoNone ; ZehuaJiaNone ; Libin LiNone ; Wang LuNone ; Yingming MaNone ; Liangting SunNone ; Hui WangNone ; Xuezhen ZhangNone ;Hongwei ZhaoNone

1 IMP/CAS, Lanzhou; University of Chinese Academy of Sciences, Beijing)


LECR5 (Lanzhou Electron Cyclotron Resonance ionsource No. 5) is an 18 GHz room temperature ECRion source featuring Ø80 mm ID (Internal Diameter)plasma chamber and high magnetic fields. It hasbeen successfully constructed at IMP recently and hasbeen fully commissioned to meet the requirements ofSESRI (Space Environment Simulation and ResearchInfrastructure) project. According to the test results,LECR5 can meet the requirements of SESRI withsufficient beam intensities within the required thetransverse emittances. As LECR5 is designed to beoptimal for the operation at 18 GHz, we havemanaged to explore the source performance at 18GHz with a maximum microwave power around 2 kW.Recent source test indicates, LECR5 can produce notonly high intensity ion beams such as 2.12 emA O6+,121 e¿A of Ar14+, 73 e¿A of Kr23+, 145 e¿A of

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Xe27+, but also very high charge state ion beamssuch as 22 e¿A of Bi41+. This paper will present therecent progress with LECR5, especially the intenseion beam production and the beam qualityinvestigation.

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Status of the AISHa Ion Source at INFN-LNSLuigi Celona1 ; Giuseppe CastroNone ; Francesco ChinesNone ; Santo GamminoNone ; Ornella LeonardiNone ; GiovanniMannoNone ; David Mascali1 ; Antonio MassaraNone ; Santi PassarelloNone ; Davide SiliatoNone ; Giuseppe TorrisiNone ;Claudio MaugeriNone ; Filippo RussoNone

1 INFN-LNS

Corresponding Author(s): [email protected], [email protected]

The AISHa ion source is an Electron CyclotronResonance Ion Source designed to generate highbrightness multiply charged ion beams with highreliability, easy operations and maintenance forhadrontheraphy applications. The R&D performed bythe INFN-LNS team during the 2019/2020 hasallowed the improvement of the AISHa performancesup to 20% for some of the extracted beams: bothinjection and extraction flanges has been improvedand a movable electrode has been installed. The lowenergy beam transport has been equipped of anEmittance Measurement Unit (EMU), working throughthe beam wire scanners principle, for themeasurement of the vertical and horizontal emittanceof the beams of interest for hadrontherapyapplications. Beam emittance has been characterizedas a function of q/m and of the beam intensity tohighlight space charge effects. If necessary, thebeam wire scanners can be used for thecharacterization of the beam shape. The perspectivesfor further developments and plasma diagnostics willbe also highlighted.

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GismoGasdynamic ECR Ion Source Status: TowardsHigh-IntensityIon Beams of SuperiorQualityIvan Izotov1 ; Alexei BokhanovNone ; Vadim SkalygaNone ; Sergey Sergeevich VybinNone

1 IAP/RAS, Nizhny Novgorod

GISMO, a CW high-current quasi-gasdynamic ECR ionsource, is under development at the IAP RAS. Thequasi-gasdynamic confinement regime, featuring highplasma density (up to 10^14 cm^-3) and moderateelectron temperature (~100 eV), allowed to extractpulsed beams of H+ and D+ ions with current of 450mA and RMS emittance <0.07 pi mm mrad*. It has

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been already demonstrated that major benefits ofquasi-gasdynamic confinement, previously tested inpulsed mode, are scalable to the CW operationalmode. In first experiments at GISMO facility, the ionbeams were extracted in pulsed mode from the CWplasma of ECR discharge due to technical limitationsof cooling circuits. Proton beams with current up to70 mA were achieved at extraction voltage of 40 kV.A new unique extraction system especially effectivefor the formation of high current density ion beamswas developed and tested. Latest results of beamcurrent, emittance and charge state distributionmeasurements are presented. Another possibleapplication of a quasi-gasdynamic plasma might bethe intense source of vacuum ultraviolet radiation(VUV). Results of VUV measurements performed atGISMO facility are also presented.

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Status of the 45 GHz MARS-D Ion SourceDaniel Xie1 ; Janilee Yvette BenitezNone ; Michel Kireeff CovoNone ; Adrian HodgkinsonNone ; Mariusz JuchnoNone ;Larry PhairNone ; Damon ToddNone ; Li WangNone

1 LBNL, Berkeley, California

Development of the MARS-D ECR ion source, a 45GHz next generation ECRIS using a NbTi MARSmagnet,has been continuously moving forward atLBNL. Recent stress analyses and other keycomponents of the MARS-D ion source have beenessentially finalized. This article presents anddiscusses the status of this new 45 GHz ECR ionsource, such as the latest design features and thefabrication plan with funding available in the verynear future.

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Conceptual Design ofHeavy Ion ToF-ERDAFacility Based on Per-manent Magnet ECRIS and Variable Frequency RFQ Accelerator

Olli Tarvainen1 ; Dan FairclothNone ; Alan LetchfordNone ; Jaakko JulinNone ; Taneli KalvasNone

1 UKRI-STFC-RAL-ISIS


Ion beam analysis is typically based on tandemaccelerators and negative ions. The required 5-20MeV energies for heavy ion time-of-flight elasticrecoil detection analysis(ToF-ERDA) can beachieved with a high charge state ion source and RFQaccelerator. We present a conceptual design of a ToFERDAfacility based on a permanent magnet ECRIS

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and variable frequency RFQ accelerating 1-10 pnA of40Ar8+, 84Kr17+ and 129Xe24+ ions to 4-7, 10-15and 13-20 MeV. We present the PM ECRISrequirements focusing on the CUBE-ECRIS* with aquadrupole min-B field topology. Beam dynamicsstudies demonstrating good transmission of theheavy ion beams from the ion source to the RFQentrance through the electrostatic low energy beamtransport (LEBT) and a permanent magnet dipole arepresented. The predicted LEBT transmissions of theCUBE-ECRIS (rectangular extraction slit) and aconventional ECRIS (circular extraction aperture) arecompared. The conceptual design of the RFQ isdescribed and the implications of the energy spreadon the high energy beam transport are discussed. Itis demonstrated that an energy spread below 0.2 %is necessary for appropriate resolution of the heavyion ToF-ERDA.

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FRIB 28 GHz ECR Ion Source Development and Status

Haitao Ren1 ; Nathan Bultman1 ; Guillaume Machicoane2 ; Philip Morrison1 ; Mykola Omelayenko1 ; Xing Rao1 ;Helene FeliceNone ; Ray HafaliaNone ; Heng PanNone ; Soren PrestemonNone

1 FRIB, East Lansing, Michigan2 Facility for Rare Isotope Beams


To satisfy ultimate performance requirements forheavy ions, a 28 GHz superconducting ECR ion sourceis under development at the Facility for Rare IsotopeBeams (FRIB) in collaboration with Berkeley NationalLaboratory. The construction and testing of thesuperconducting magnet was completed at Berkeleyand delivered to FRIB in January 2018. The magnetand cryostat have been assembled on the highvoltage platform. Magnet cooldown and field mappingare planned by the end of 2020. The sourcecommissioning shall start in early 2021. Details of theion source design, current status of assembly, andcommissioning plan will be presented in this paper.

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Imaging in X-ray Ranges to Locally Investigate the Effect of theTwo- Close-Frequency Heating in ECRIS Plasmas

Richard Racz1 ; Sandor BiriNone ; Zoltan PerdukNone ; Eugenia NaselliNone ; Alessio GalataNone ; Giuseppe CastroNone; Luigi CelonaNone ; Santo GamminoNone ; David MascaliNone ; Maria MazzagliaNone ; Giuseppe TorrisiNone ; JozsefPalinkasNone

1 Atomki, Debrecen

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Plasma instabilities limit the ECR Ion Sourcesperformances in terms of flux of the extracted highlycharged ions by causing beam ripple and unstableoperation conditions. In a 14 GHz ECRIS (Atomki,Debrecen), the effect on the plasma instabilities in anArgon plasma at Two Close Frequencies heatingscheme (the frequency gap is smaller than 1 GHz)has been explored. A special multi-diagnostic setup[1, 2] has been designed and implemented consistingof detectors for the simultaneous collection of plasmaradio-self-emission and of high spatial resolutionX-ray images in the 500 eV - 20 keV energy domain(using an X-ray pin-hole camera setup). We presentthe comparison of plasma structural changes asobserved from X-ray images in single and doublefrequencyoperations. The latter has been particularlycorrelated to the confinement and velocityanisotropy, also by considering results coming fromnumerical simulations.

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High Resolution X-ray Imaging as a Powerful Diagnostics Toolto Investigate ECRIS Plasma Structure and Confinement Dynam-icsEugenia Naselli1

1 INFN/LNS, Catania University

High resolution spatially-resolved X-ray spectroscopy, by means of a X-ray pin-hole camera setup*operating in the 0.5-20 keV energy domain, is a very powerful method for ECRIS plasma structureevaluation. We present the setup installed at a 14 GHz ECRIS (ATOMKI, Debrecen), including amulti-layered collimator enabling measurements up to several hundreds of watts of RF pumpingpower and the achieved spatial and energy resolution (0.5 mm and 300 eV). Results coming by anew algorithm for analyzing Integrated (multi-events detection) and Photon-Counted images (single-event detection) to perform energy-resolved investigation will be described. The analysis permits toinvestigate High-Dynamic-Range (HDR) and spectrally resolved images, to study the effect of theaxial and radial confinement (even separately), the plasma radius, the fluxes of deconfined electronsdistinguishing fluorescence lines of the materials of the plasma chamber (Ti, Ta) from plasma (Ar)fluorescence lines. This method allows a detailed characterization of warm electrons, important forionization, and to quantitatively estimate local plasma density and spectral temperature pixel-by-pixel.

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TheRelationship Between theDiffusion ofHot Electrons, PlasmaStability, and ECR Ion Source PerformanceBryan Christopher Isherwood1 ; Guillaume Machicoane2

1 MSU2 Facility for Rare Isotope Beams


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Plasma instabilities complicate the operation of electron cyclotron resonance ion sources. In partic-ular, quasi-periodic losses of electrons from confinement due to kinetic cyclotron instabilities hinderion source performance. Empirical scaling laws help guide the development of sources away fromthe most unstable operating points but are poorly understood. Further advancement of ECR ionsource technologies requires a deeper understanding of instabilities, scaling laws, and internal pro-cesses of the ion source plasma itself. We present here results of an experimental study into theseinstabilities and scaling laws, and measurements of hot electron diffusion (E > 10 keV) from the 18GHz SUSI ECRIS at the NSCL. Measurements of the average argon current and the standard devia-tion of their variations across multiple unstable operating points are shown. These measurementsare compared to measurements of electrons that diffuse axially from the plasma chamber. In doingso it will be shown how controlling the diffusion of electrons control the stability of the plasma andoptimize the ion source’s performance.

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Production of 48Ca and 48Ti Ion Beams at the DC-280 Cyclotron

Dmitry PugachevNone ; Sergey Bogomolov1 ; Andrey Bondarchenko1 ; Andrey EfremovNone ; Konstantin IgorevichKuzmenkovNone ; Aleksander LebedevNone ; Vladimir LoginovNone ; Vladimir Mironov2

1 JINR2 Joint Institute for Nuclear Research, Dubna, Moscow Region, 141980 Russia

CorrespondingAuthor(s): [email protected], [email protected], [email protected], [email protected]

The heaviest known elements (up to 118Og) weresynthesized at the U-400 cyclotron (FLNR JINR,Dubna) by using a beam of 48Ca ions. During thetests of the DC-280 cyclotron, intense beams of 48Caions were produced. For the synthesis of theelements 119 and heavier, intense and stable beamsof medium-mass elements are required, such as 50Tiand 54Cr. Before starting the main experiments, wetest the production of 48Ti ion beam, which is lessexpensive than 50Ti. The article describes themethod, technique, and experimental results on theproduction of 48Ca and 48Ti ion beam at the DC-280cyclotron from the DECRIS-PM ion source.

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ECR Discharge in Solenoidal Magnetic Field as a Source of DenseWide- Aperture Plasma FluxesIvan Izotov1 ; Alexei BokhanovNone ; Sergey GolubevNone ; Mikhail Yurevich KazakovNone ; Sergey RazinNone ; RomanShaposhnikovNone ; Sergey ShlepnevNone ; Vadim SkalygaNone

1 IAP/RAS, Nizhny Novgorod

Sources of dense plasma fluxes with wide apertureare extensively used in applied science, i.e. surfacetreatment, and as a part of neutral beam injectors.ECR discharge in a solenoidal magnetic field (i.e. withno magnetic mirrors for plasma confinement),sustained by a powerful radiation of moderngyrotrons is under consideration at IAP RAS as a

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possible alternative to widely used vacuum arc, RFand helicon discharges. The use of a high frequencyradiation (37.5 GHz) allows to obtain a discharge atlower pressure, sustain almost fully ionized plasmawith density more than 10^13 cm^-3, whereas thepower on the level of several hundreds of kW allowsone to create such a plasma in considerably largevolume. In the present work fluxes of hydrogenplasma with the equivalent current density of 750mA/cm2 and the total current of 5 A were obtained. Amulti-aperture multi-electrode extraction systemdesign capable of forming the non-divergent ionbeam was developed with the use of IBSimu code.

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Stable and Intense 48Ca Ion Beam Production With a MicrowaveShielded Oven and an Optical Spectrometer as Diagnostic Tool

FabioMaimone1 ; RalphHollingerNone ; Ralf LangNone ; JanMaederNone ; Patrick Tedit PatchakuiNone ; Klaus TinschertNone; Alexander AndreevNone

1 GSI, Darmstadt

The CAPRICE ECRIS installed at the High ChargeInjector (HLI) of GSI produces highly charged ionbeams from gaseous and metallic elements. A highdemand of metal ions comes from the nuclearphysics, material re-search, and Super HeavyElement group (SHE), and the most requestedelement, besides 50Ti, is 48Ca. When this chemicalreactive material is deposited inside the plasmachamber at internal components the stability can becom-promised. Furthermore, it is difficult to find aworking point to guarantee a long-term stability asthe oven re-sponse time and the reaction of theECRIS are relatively slow. The monitoring by using anOptical Emission Spectrometer (OES) facilitatesimmediate reactions when-ever plasma instabilitiesoccur. For this reason, a real-time diagnostic systembased on an OES has been in-stalled at the ECRIS atHLI for routine operation during the beam-time 2020.The measured spectra revealed a parasitic ovenheating by coupled microwaves often com-promisingthe ion source performance. Therefore, a tung-stengrid has been installed to shield the oven orifice fromthe coupled microwaves. The results in terms of 48Cabeam intensity and stability are reported here.

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New Metallic Stable Ion Beams for GANILFrederic Lemagnen1 ; Christophe BarueNone ; Mickael DuboisNone ; Romain FrigotNone ; Nicolas LechartierNone ;Vincent MetayerNone ; Benoit OsmondNone

1 GANIL, Caen

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GANIL has been producing many stable beams fornearly 40 years. Constant progress has been made interms of intensity, stability and reliability. Theintensity for some stable metallic beams now exceedsor approaches the pμA level at an energy up to 95MeV/u: 1.14 pμA for 36S (65% enriched) at 77MeV/u, 0.35 pμA for 58Ni (63%) at 74 MeV/u. Thepresentation highlights recent results obtained for28Si, 184W and 130Te using the GANIL s LCO(Large Capacity Oven) on the ECR4 ion source. Toproduce the tungsten beam, two injection methodswere compared. For the first one, we evaporatedsome tungsten trioxide (WO3) with GANILs LCO.For the second one, the injection in the plasmachamber was made by using MIVOC (Metallic Ionsfrom VOlatile compounds) with a tungstenhexacarbonyl (W(CO)6) compound. It was the firsttime that we used metal carbonyl compounds and theresult is promising. All the tests have been qualifiedto obtain the level of intensity and beam stability.Theses good results led us to propose them forPhysics experiments.

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ANew Resistive High Temperature Oven for Metallic Beams Pro-ductionOlivier Bajeat1 ; Christophe BarueNone ; Mickael DuboisNone ; Frederic Lemagnen1 ; Matthieu MichelNone

1 GANIL, Caen

For the Super Separator Spectrometer (S3) [1]currently under construction on Spiral 2 facility,metallic beams of high intensities must be deliveredto impinge a target aiming to produce rareradioactive isotopes for fundamental nuclear studies.First requested beams are 58Ni, 48Ca, 50Cr, 50Ti or50V with an intensity about 1,2.1013 pps. Themetallic ion beams will be produced by the PhoenixV3 ECR ion source combined with a resistive ovennewly designed to cope with the beam specifications.The evaporation of low vapor pressure metallicelements (Ti, V…) requires temperature within arange of 1900℃ to 2000℃. A new design of aresistive oven has been developed for this purpose.The oven reached 2000℃ in a test vacuum chamberduring 8 days. It has worked out in the ElectronCyclotron Resonance Ion Source ECR4 at GANIL forTitanium beam production. Further tests using thision source are under preparation for Ti and V beamproduction. Flux and angular distribution of atomsreleased by the oven are going to be measured offlinefor optimizing crucibles geometries. Finally, theoven will be integrated into the Phoenix V3 ECRIS forTi and V production.

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Microcontrollers asGate andDelayGenerators forTimeResolvedMeasurementsBryan Christopher Isherwood1 ; Guillaume Machicoane2 ; Eduard Pozdeyev3

1 MSU2 Facility for Rare Isotope Beams3 Fermilab


The diffusion of electrons from ECRIS plasmas resultsin the emission of bremsstrahlung distributions fromthe plasma chamber. ECRIS bremsstrahlungmeasurements that are both time- and energyresolvedare often challenging to perform due to the10’s; 100’s ms timescale that the plasma evolvesover. However, the advancement of low-costmicrocontrollers over the last decade makes timingand gating photon spectrometers easier. We presenta proof of principle measurement which uses anArduino microcontroller as a gate-and-delaygenerator for a High Purity Germanium (HPGe)detector. An example plot of the time-resolvedbremsstrahlung spectrum, triggered by beam currentvariation induced by kinetic instabilities, is shown.

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Plasma Parameters at Upper/down Stream Region Near Ecr Zoneand Optimizing Microwave-Launching on ECRISWataru Kubo1 ; Shuhei Harisaki2 ; Yushi KatoNone ; Issei OwadaNone ; Koichi SatoNone ; Kazuki TsudaNone

1 Osaka University, Osaka2 Osaka University


We have investigated how to produce multichargedions efficiently. Recently, we have focused on wavespropagations in plasma and conducted the UpperhybridResonance (UHR) experiments. [1] We havealso conducted experiments heating by the coaxialsemi-dipole antenna to enhance the right-handpolarization wave, which contributes to ECR. [2]Multicharged ion beams have been improved usingvarious means, e.g., the increase of the magneticfield and the microwave frequency, the DC biasedplate-tuner, mixing low z gases, and the multiplexfrequencies heating. However, the microwavelaunching position has been empirically determinedon conventional ECRIS’s. There is still some room forimprovement with the respect to more efficientexcitation of the wave propagation. In this research,we estimate the wave propagation near the ECRzone, and in the opposite peripheral region beyond it.We measure plasma parameters in those regions bytwo Langmuir probes inserted into each location atthe same time. In near future, we optimize the

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microwave-launching in the case of the fundamentalfrequency for ECR and the second frequency for UHRin order to enhance their incidence to the vacuumchamber.

26

Tentative Solution to Plasma Chamber Cooling for High PowerECR Ion Source OperationJunwei Guo1 ; Yucheng FengNone ; Denis HitzNone ; Jibo LiNone ; Libin LiNone ; Lixuan Li2 ; Wang LuNone ; JindouMaNone ; Yangyang YangNone ; Wenhui ZhangNone ; Xuezhen ZhangNone ; Hongwei ZhaoNone ; Wei Huang3 ; LiangtingSun4

1 IMP/CAS, Lanzhou2 IMP/CAS3 Institute of Modern Physics4 Institute of Modern Physics, CAS


High charge state electron cyclotron resonance ionsource (ECRIS) is characterized by a so-called min-Bmagnetic field configuration, which provokes thelocalized plasma over-heating to plasma chamberespecially for the 3rd generation ECRISs at highpower operation condition. With the increase of rfpower, more plasma energy will be dumped to tinyareas and result in a very high localized powerdensity, which is estimated to be up to 1 kW/cm2.Few existing ECR plasma chamber cooling designscan withstand such high heat fluxes. In this paper,we report a new plasma chamber cooling design withso-called Micro-channel cooling technology, which cannot only realize efficient heat transfer, but alsoretains a small radial thickness that is beneficial forthe radial magnetic field. In order to evaluate theperformance of the cooling structure with microchanneldesign, experimental cooling loop for highheat flux has been designed and built at IMP. Initialexperiments demonstrate that optimizedconfiguration can achieve high heat flux cooling in therange of 1 kW/cm2 and beyond. Based on theseresults, a plasma chamber with micro-channel designfor SECRAL has been designed and tested.

27

Development of HTO with Inductive Technology for UraniumBeam ProductionWang Lu1 ; Libin LiNone ; Lixuan Li2 ; Xuezhen ZhangNone ; Hongwei ZhaoNone ; Wei Huang3 ; Liangting Sun4 ; ChengQianNone ; Junwei GuoNone

1 IMP/CAS, Lanzhou2 IMP/CAS

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3 Institute of Modern Physics4 Institute of Modern Physics, CAS

Corresponding Author(s): [email protected], [email protected], [email protected]

A High-Temperature Oven (HTO) with inductiveheating technology has been developed successfullyin 2019 at Institute of Modern Physics. This ovenfeatures durable operation temperature of >2000℃inside the tantalum susceptor. By careful design theoven structure, material compatibility and thermalstress issues at high temperature has beensuccessfully handled, which enables the production of

400 eμA U33+ with SECRAL-II*. With necessaryrefinement, this type of oven could also be availablewith room temperature ECR ion sources, like LECR4and LECR5. Some improvements in structure havebeen proposed in this year. The design and testingresults will be presented in this contribution.

7

Influences of Magnetic Field Parameters to ECRIS Plasma Char-acteristicsJibo Li1

1 IMP/CAS

To investigate the hot electron population and the appearance of kinetic instabilities in ECRIS plasma,the axially emitted bremsstrahlung spectra and microwave bursts emitted from ECRIS plasma weresynchronously measured on SECRAL-II ion source with various magnetic field configurations. Theexperimental results show that when Bmin/Becr is less than ~0.8, the spectral temperature Ts in-creases linearly with the Bmin/Becr-ratio when the injection, extraction and radial mirror fields arekept constant. Above this threshold Ts saturates and the electron cyclotron instability appears si-multaneously. This study has also demonstrated that Ts decreases linearly with the increase of theaverage gradient over the ECR surface when the on-axis gradient and hexapole field strengths areconstant. In addition, it is found that Ts decreases with the increase of the gradient at the resonancezone at relatively low mirror ratio and is insensitive to the gradient at high mirror ratio when Bminis constant. Compared to a recent study taken on a fully superconducting ECRIS, this study showsdifferent results discussing the mechanisms behind the correlation of magnetic field parameters toTs.

28

A Theoretical Model of High-Bmin Instabilities and Experimen-tal Tests of Its PredictionsDamon Todd1 ; Janilee Yvette BenitezNone

1 LBNL, Berkeley, California

It is well known that ECR ion sources exhibitinstabilities when the source’s minimum magnetic

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field is approximately 80% of the resonant field orgreater, but the reasons for this instability have yetto be satisfactorily explained. In this paper wepresent a simple theoretical model that has the highminimum-B instability as a consequence. We showthat this model predicts modes of operation withhigh-minimum B that avoid that instability (includingmultiple-frequency heating), and present results fromexperimental tests of some of these predicted stablemodes.

29

Experimental Evidence ofTrappedWaves in a SimpleMirrorMagnetic-Trap

Giuseppe Castro1 ; Santo GamminoNone ; David Mascali2 ; Giuseppe TorrisiNone ; Rosalba MiracoliNone ; LuigiCelona2

1 INFN/LNS, Catania2 INFN-LNS


This work presents the first experimentalcharacterization of cavity modes trapped within aplasma column in an axis-symmetric magnetic trap.Trapped wave has been characterized by means of amovable antenna as a function of the B_{min}/B_{ECR} ratio and plasma parameters. The studydemonstrates that E.M waves can be trappedbetween two R-cutoff layers, in proximity of the Bminimum position. Results suggest that the trappedwaves consist of Whistler waves, propagatingperpendicularly to the magnetic field and storinglarge part of the E.M power introduced in the plasmachamber. If R-cut-off is removed by increasing thedensity, trapped waves are not detected anymore. Atypical Electron Energy Distribution Functioncomposed by two different electron populations ismeasured in the layer where trapped waves arerevealed, suggesting that additional heating isoccurring. The existence of trapped waves in aplasma column was already foreseen by severalstudies concerning the development of kineticinstability in plasmas and this experimentalcharacterization allows to shed more light on nonlinearplasma coupling and to the generation ofsupra-thermal electrons in ECRIS plasmas.

30

Simulation andExperimental Investigation of an Ion SourceMetal-lic OvenThomas Thuillier1 ; Olivier BejeatNone ; Laurent Maunoury2 ; Alexandre LeducNone

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1 LPSC, Grenoble Cedex2 GANIL


Oven are widely used to produce metallic ion beamsin ECRIS. A calcium oven dedicated to metalevaporation up to 650℃ has been investigated bysimulation and experience. The differential atomemittance has been measured and is well reproducedby the results of a Monte-Carlo simulation code. Theabsolute atom flux was measured as a function of theoven temperature and compared with theoreticalpredictions. A quite good agreement is obtained withtheory and new values of Antoine’s coefficient forcalcium are proposed. The simulation is used toinvestigate the probability of on flight atom ionizationby the plasma as a function of the oven distance tothe ECR zone. With the PHOENIX V3 geometry, whenthe oven is placed in the injection biased disk plane,the ionization efficiency is 14%. This value in quitegood agreement with experiment. Theoreticalefficiency up to 57% is reachable when the ovendistance is reduced to 1 cm to the ECR zone.

31

Progress in Self-ConsistentModeling of Time- and Space-DependentPhenomena in Ecris PlasmaAngelo Pidatella1 ; Bharat MishraNone ; David Mascali2 ; Giuseppe TorrisiNone ; Eugenia NaselliNone ; Alessio Galatà3

1 INFN/LNS, Catania2 INFN-LNS3 INFN-Legnaro National Laboratories


Resonant interaction with the microwave radiation inECRIS plasma leads to a strongly anisotropic electronenergy distribution function (EEDF), given as acombination of two to three electron populations,with the possibility to trigger kinetic instabilities. Atthe INFN, further efforts have been paid to improveand update self-consistent 3D numerical codes forplasma electrons kinetics. Progresses have openedseveral perspectives. It is now possible to derivespace-resolved EEDF, and compute space-dependentenergy and density maps. Also, the code has beenupdated to provide reaction rates of electromagneticemissions, including X-ray fluorescence. An estimateof the local ion charge state distribution is potentiallypossible, and first evaluations are ongoing. Dealingwith fast-transient mechanisms, such aselectromagnetic emission via the electron-cyclotronMASER instability, the code is now updated for locallyevaluating the EEDF anisotropy. We will present thecollected results, which we believe to have a relevantimpact both on the ECRIS plasma physics and on theINFN’s PANDORA project that plans to use ECR

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plasmas for fundamental studies in Nuclear andAstroNuclear Physics.

32

A Guiding Centre Approximation Approach for the Simulationof Electron Trajectories in ECR and Microwave Ion SourcesJose Antonio Mendez1

1 LPSC, Grenoble Cedex

The Boris algorithm has become the standard forparticle trajectory integration in a magnetic field. Thehigh frequency electron cyclotron motion (GHz)constrains the time-step below 10 ps. A guidingcentre approach neglects the detailed particlecyclotron motion, describing its trajectory throughfree motion of the orbit’s centre along the field linesand corresponding drifts. It works on the assumptionthat the magnetic field strength varies in a muchlarger length scale than the cyclotron orbit. Thisapproach is more computationally expensive per stepthan direct orbit integration, but a shorter overallcomputation time may be expected by using a largertime-step (~100 ps). This work presents a study onimplementing the guiding centre approach in ECR ionsources. It is shown to reproduce accurately thetrajectory drifts and confinement of electrons in aminimum-B field, but the use of long time-stepsexacerbates a non-physical kinetic energy loss.Following, non-confined electron trajectories in aflatter field are analysed, as in a microwave dischargeion source, where this method’s drawbacks areavoided due to a smaller magnetic field gradient anda shorter electron lifetime.

33

Electromagnetic Simulation of ’plasma-shaped’ PlasmaChamberfor Innovative ECRISGiorgio SebastianoMauro1 ; Ornella LeonardiNone ; David Mascali2 ; Angelo Pidatella3 ; Filippo RussoNone ; GiuseppeTorrisiNone ; Alessio Galatà4 ; Carmelo Sebastiano GalloNone ; Gino SorbelloNone

1 INFI/LNS, Catania2 INFN-LNS3 INFN/LNS, Catania4 INFN-Legnaro National Laboratories


The plasma chamber and injection system designplay a fundamental role in ECRISs with the aim toobtain an optimized electromagnetic fieldconfiguration able to generate and sustain a plasma

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with a high energy content. In this work we presentthe numerical study and the design of anunconventionally-shaped cavity resonator* thatpossesses some key advantages with respect to thestandard cylindrical cavities, usually adopted in ionsources setups. The cavity geometry, whose designhas been completed on January 2020, has beeninspired by the typical star-shaped ECR plasma,determined by the magnetic field structure. Thechamber has been designed by using the commercialsoftwares CST and COMSOL, with the aim tomaximize the on-axis electric field. Moreover, aradically innovative microwaves injection system,consisting in side-coupled slotted waveguides, hasbeen implemented, allowing a better power couplingand a more symmetric power distribution inside thecavity with respect to the standard rectangularwaveguides. This new ‘plasma-shaped oriented’design could relevantly improve the performances ofthe ECRISs while making more compact the overallsetup.

34

Characterization of 2.45GHzECR Ion SourceBench forAccelerator-Based 14-MeV Neutron GeneratorSudhirsinh J Vala1 ; Mitul AbhangiNone ; Mainak BandyopadhyayNone ; Rajesh KumarNone ; Ratnesh KumarNone

1 Institute for Plasma Research, Bhat, Gandhinagar

The 2.45 GHz Electron Cyclotron Resonance IonSource (ECRIS) has been indigenously developed.This development of ECRIS aims to provide highbrightness, stable, and reliable D+ ion beam of 20mA in continuous (CW) mode operation foraccelerator-based D-T neutron generator. The ECRion source setup consists of a microwave system, amagnet system, a double wall water-cooled plasmachamber, a high voltage platform, a three-electrodeion extraction system, and a vacuum system. TheECR ion source test setup is installed and deuteriumplasma generated. Three-electrode extraction systemis designed and fabricated for the ion beamextraction. A ~10 mA deuterium ion beam isextracted from the ECR ion source. The paper coversthe detailed experimental setup of ion beamcharacterization and diagnostics used formeasurement of beam profile, beam current, andbeam emittance measurements. It also covers thelatest results of beam profile, and beam currentmeasurement as a function of extraction voltage, gasflow, and acceleration voltage.

35

Electron Cyclotron Resonance Ion Source Related Research and

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Development Work at the Department of Physics, University ofJyväskylä (JYFL)Miha Marttinen1 ; Hannu KoivistoNone ; Anssi IkonenNone ; Taneli KalvasNone ; Sami KosonenNone ; Risto JuhaniKronholmNone ; Ville ToivanenNone ; Laurent Maunoury2 ; Ivan Izotov3 ; Vadim SkalygaNone ; Bichu Subhash BhasiBhaskar 4 ; Julien ANGOT5 ; Thomas Thuillier6 ; Olli Tarvainen7

1 University of Jyväskylä, Department of Physics2 GANIL3 IAP/RAS, Nizhny Novgorod4 LPSC, JYFL5 Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 38000 Grenoble, France6 LPSC, Grenoble Cedex7 UKRI-STFC-RAL-ISIS


Recent research work of the JYFL ion source teamcovers multi-diagnostic studies of plasma instabilities,high-resolution plasma optical emission spectroscopy,ion current transient measurements to define thetotal life-time of a particle in the highly chargedplasma. The JYFL team also elaborates the magneticand technical design of the unconventional ion sourcenamed CUBE. The R&D work includes, in addition, thecommissioning and operation of the highperformance18 GHz ECRIS, HIISI. The instabilitymeasurements have revealed new information aboutthe parameters affecting the onset of the plasmainstabilities and shown that different instability modesexist. The ion-beam transient studies have giveninformation about the cumulative life-time of highlychargedions convergent with the ion temperaturesdeduced from the Doppler broadening of emissionlines. The CUBE prototype has a minimum-Bquadrupole magnetic field topology, similar to ARCECRIS,and its all-permanent magnet structure hasbeen optimized for 10 GHz frequency. The CUBEdesign will be presented along with its commissioningstatus. The status and operational experience withHIISI will be reported as well.

9

Study on the Correlation between Energy Distribution of Elec-trons Lost from the Confinement and Plasma Bremsstrahlung ona min-B ECR PlasmasBichu Subhash Bhasi Bhaskar 1

1 LPSC, JYFL

The study of plasma bremsstrahlung has been used as a diagnostic tool for understanding the behav-ior of confined plasma in Electron Cyclotron Resonance Ion Sources (ECRIS). In order to understandthe relation connecting the confined plasma and the electrons escaping the confinement, a seriesof measurements have been made to measure the bremsstrahlung produced in the axial and radialdirection along with the Lost Electron Energy Distribution (LEED) axially on JYFL 14 GHz ECR. Wepresent here the effect of various source parameters on the axial and radial bremsstrahlung along

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with the LEED on a min-B confined ECR plasma. The measured LEED has been found to show a cor-relation with bremsstrahlung measurement and also have observed as a potential diagnostic methodfor instability. The explanation for observed LEED and bremsstrahlung trends is provided.

36

Ultra-High Current Density Produced by a 60 Ghz Ecr Ion Source

Thomas ANDRE1 ; Julien ANGOT2 ; Maud BaylacNone ; Josua JacobNone ; Patrick SoleNone ; Thomas Thuillier3 ;Francois DebrayNone ; Ivan Izotov4 ; Vadim SkalygaNone

1 LPSC-CNRS2 Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 38000 Grenoble, France3 LPSC, Grenoble Cedex4 IAP/RAS, Nizhny Novgorod


SEISM is a compact ECR ion source operating at 60GHz developed up to 2014. The prototype uses amagnetic cusp to confine the plasma. This simplemagnetic geometry was chosen to allow the use ofpolyhelix coils (developed at the LNCMI, Grenoble) togenerate a strong magnetic confinement featuring aclosed ECR surface at 2.1 T. The plasma is sustainedby a 300 kW microwave pulse of 1 ms duration andwith a 2 Hz repetition rate. Previous experiments atLNCMI have successfully demonstrated theestablishment of the nominal magnetic field and theextraction of ion beams with a current density up to~ 1A/cm2. The presence of “afterglow” peaks wasalso observed, proving the existence of ionconfinement in a cusp ECR ion source. The last runwas prematurely stopped but the project restarted in2018 and new experiments are planned in 2021. Anew transport beam line has been designed toimprove ion beam transport towards the beamdetectors. Short- and long-term research plans arepresented, including numerical simulations of thebeam transport line and future upgrades of the ionsource with the main goal to transform the highcurrent density measured into a real high intensityion beam.

37

Multi-Species Child-Langmuir Law with Application to ECR IonSourcesChun Yan Jonathan WongNone

We generalize the classical single-species Child-Langmuir Law to analyze multi-species beams fromECR ion sources. The formulation assumes therelative weight of each species in the extracted beamis known. We applied the results to charge state

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distribution data from Artemis- and Venus-typesources at the NSCL and LBNL respectively. The totalmeasured beam current is close to the maximumcurrent predicted by the multi-species Child LangmuirLaw in each case, which indicates that beamextraction occurs around the regime of space chargelimited flow. Prospects for application of the resultsand further studies on the topic are outlined.

38

BeamswithThree-FoldRotational Symmetry: ATheoretical Study

Chun Yan Jonathan WongNone

Beams from ECR ion sources have 3-fold transverserotational symmetry induced by the ECR sextupole.The symmetry imposes equality constraints amongtransverse beam moments, which can be derivedusing a theoretical framework we developed. Sincethe constraints are solely a consequence of therotational symmetry of external fields, they hold forarbitrary charge state distribution and space chargeintensity. These constraints provide a new tool toanalyze phase space properties of ECR beams andtheir impact on low-energy transport. We prove that,regardless of their triangulation, beams with 3-foldrotational symmetry have the same rms emittanceand Twiss parameters along any transverse direction.These counter-intuitive results are applied to theFRIB Front End to demonstrate how symmetryarguments challenge long-standing assumptions andbring clarity to the beam dynamics.

39

Improvement of theCryostat SystemPerformance of 28-GhzElec-tron Cyclotron Resonance Ion Source of the Biba by a RadiationShieldingMi-Sook Won1 ; Jung-Woo OkNone ; Jin Yong ParkNone ; Seongjun KimNone

1 Korea Basic Science Institute, Busan

The BIBA (Busan Ion Beam Accelerator) is a compactlinear accelerator facility using the 28 GHz ECRIS atthe KBSI (Korea Basic Science Institute). Our goal isto generate high current fast neutrons using theheavy ion interaction with a proton target. For astable operation of the superconducting magnets, theperformance of cryostat system is very essential atthe 28 GHz ECRIS. However, the emitted x-ray frominner plasma chamber contributes to increase anextra heat load to the cryostat system by absorbingthe cold mass of the superconducting magnet.Therefore, we have measured X-ray spectra from the

Page 18


28 GHz ECR ion source and tried to improve theperformance of the Cryostat System by a radiationshielding. In this paper, we will present the testresults of X-ray emission on 28GHz KBSI ECRIS andimproved cooling system performance.

40

Precise Identification of Extracted Ion Beam Spectrum InitiallyObtained in Synthesizing Iron-Endohedral Fullerenes on ECRIS

Issei OwadaNone ; Shuhei Harisaki1 ; Yushi KatoNone ; Wataru Kubo2 ; Takayuki OmoriNone ; Koichi SatoNone ; KazukiTsudaNone ; Atsushi KitagawaNone ; Masayuki MuramatsuNone ; Yoshikazu YoshidaNone

1 Osaka University2 Osaka University, Osaka


Electron cyclotron resonance ion source (ECRIS)plasma has been constructed for producingsynthesized ion beams in Osaka Univ.[1,2] We hopethat it can become a universal source capable ofproducing ions with wide range mass/charge ration(m/q). We have been trying to produce endohedralfullerenes in the ECRIS. We have conducted initialexperiments on production of them only in thesecond stage of ECRIS. We have been using ironvapor source by induction heating (IH) from themirror end along to the geometrical axis, and C60crucible from the side wall, respectively. Wesucceeded in realizing ECR plasma that fullerene andiron ions coexist on the single stage ECRIS, even by1kV extraction voltage.[3] By these experimentalseries, the typical CSD suggests that there ispossibility of slight formation of iron fullerenescompounds and iron endohedral fullerenes. We arecontinuing to investigate the experimental conditionsthat maximize spectrum corresponding to ironendohedral fullerenes. In this paper we describepreliminary experimental results of synthesizing ironendohedralfullerene on the ECRIS.

41

High IntensityVanadium-IonBeamProduction to Search forNewSuper- Heavy Element with Z = 119Takashi Nagatomo1 ; YoshihideHigurashiNone ; OsamuKamigaitoNone ; TakahideNakagawaNone ; Jun-ichi OhnishiNone

1 RIKEN Nishina Center, Wako

We have begun searching for the new super-heavyelement (SHE) with Z=119 at RIKEN Heavy IonLINAC (RILAC). To overcome the small production

Page 19


cross section of vanadium (V) beam on the curiumtarget, the project requires a very powerful V beam.In order to optimize the beam intensity of V with thecharge state of 13+, we have investigated the effectsof the amount of V vapor, the power of 18- and 28-GHz microwaves, and the strength of the mirror field.While no significant effect was seen by changing themirror field Bext from 1.4 T to 1.6 T, the amount of Vvapor and the microwave power strongly affected.Based on the correlation between the V-vapor andthe microwave power, we obtained a 600-euA V(13+)beam with the V consumption rate of 24 mg/h andthe microwave power of 2.9 kW in order to executeabout 1-month SHE experiment. Furthermore,because such strong mirror field enhances thetransverse beam emittance, it is important to controlthe emittance with small reduction of the intensity.We have successfully controlled the beam emittanceby using three pairs of slits (triplet slits) in LEBT byeliminating the peripheral beam components in bothof the x-x’ and y-y’ phase spaces.

8

Enhancing Production of Multicharged Ions by Pulse ModulatedMicrowaves under Low Z Gas Mixing Operation on ECRISShuhei Harisaki1

1 Osaka University

We are aiming at producing various ion beams in ECRIS. In the case of producing multicharged ionbeams, we try to enhance loss channel of lowZ ions bymeans of adding pulsemodulatedmicrowavesto conventional gas mixing method.Through these experiments, we explore the feasibility of selectivelyheating specific ions with pulse modulated microwaves and launching another low frequency RF waves.In gas mixing experiment, we use Helium as low Z gas for production of multicharged Ar and Xenonion beams. These experiments are conducted by keeping the total pressure constant and changing themixing ratio of Helium. The time scale of pulsed microwave is typically several to several hundreds ofmicroseconds. We optimize the pulse period and duty ratio for producing multicharged ion beams. Theseeffects are investigated to measure Charge State Distributions (CSDs). Also, we can measure the emit-tance using wire probe and multi slit attached to Ion Beam Irradiation System (IBIS).* We estimate thenormalized emittance from this measurement to determine index of ion temperature in the ECRIS. Inthis paper, we mainly describe the results of these active and additive methods at the ECRIS.

42

BeamProfileMeasurements of DeceleratedMulticharged Xe IonsfromECRIS for Estimating LowEnergyDamage on SatellitesCom-ponents

Koichi Sato1 ; Yushi KatoNone ; Wataru Kubo1 ; Kazuki OkumuraNone ; Issei OwadaNone ; Kazuki TsudaNone ; ShuheiHarisaki2

1 Osaka University, Osaka2 Osaka University

Page 20



Electron cyclotron resonance ion source (ECRIS) hasbeen constructed for producing synthesized ionbeams in Osaka Univ.,* Xe is used as fuel for ionpropulsion engines on artificial satellites. There areproblems of accumulated damages at irradiation andsputtering by low energy Xe ion from the engine. It isrequired to construct experimentally sputtering yielddatabases of ion beams in the low energy region fromseveral hundred eV to 1keV, since there are notenough data of satellite component materials.Therefore, we are trying to investigate experimentallysputtering yield on materials by irradiating the lowenergy single species Xeq+ ion beams. However,there is a problem that if the low extraction voltage,the amount of beam currents is not enough to obtainion beam flux for precise evaluation of sputteringyield data. Thus, we conduct to decelerate Xeq+ ionbeams required low energy region after extracting athigh voltage, e.g., 10kV. We measured thedecelerated beam profile with x and y direction wireprobes. As a result, we were able to estimate thedose of ion fluxes. We are going to conductirradiation experiments on various materials.

5

Observation of Cyclotron Instabilities in SECRAL-II Ion Source

Lixuan Li1

1 IMP/CAS

Cyclotron instabilities in Electron Cyclotron Resonance Ion Source (ECRIS) plasmas are related tonon-linear interaction between plasmawaves and energetic electrons, resulting in strongmicrowaveemission, a burst of energetic electrons escaping the plasma, and the periodic oscillations of the ex-tracted beam currents. Precedent investigation of cyclotron instabilities has proved that Bmin/BECRcan be treated as a magnetic field threshold. Recently, experiments with SECRAL-II ion sourcedemonstrate that Bmin/BECR is not the only knob, and other field parameters have also been foundto be related to cyclotron instabilities, such as mirror ratio and radial field. Namely, the trigger ofcyclotron instability is a combination of many magnetic field parameters. This paper will give theexperimental setup at IMP for cyclotron instability investigations and experimental observationswill be presented.

43

High Intensity Ion Beam Extraction System for FECRZhen Shen1 ; Xing FangNone ; Junwei GuoNone ; Zehua JiaNone ; Yuguo LiuNone ; Wang Lu1 ; Yao YangNone ; XuezhenZhangNone ; Hongwei ZhaoNone ; Liangting Sun2

1 IMP/CAS, Lanzhou2 Institute of Modern Physics, CAS


Page 21


To meet the beam requirements of High Intensityheavy ion Accelerator Facility (HIAF), the Institute ofModern Physics is developing a Fourth generationECR ion source (FECR). Targeting at the operationfrequency of 45 GHz, FECR is expected to producevery high intensity highly charged heavy ion beams,such as 1.0 emA 238U35+, 2 emA 78Kr19+, 10 emA16O6+, etc. Based on the records with the 3rdgeneration ECR ion source operating at 24~28 GHz,the corresponding total drain current of FECR couldreach 20 ~ 60 emA. To extract such high intensitymulti-charged ion beams from the source with highbeam quality and transmission efficiency,conventional diode or triode extraction system mightnot be suitable, and therefore a 4-electrodeextraction system with a total extraction voltage of50 kV is designed to mitigate the space chargeinfluences and minimize the beam emittance growthin the extraction region. In this paper, a 3D model ofthe FECR extraction system is built using the IBSimucode. The electrode angles, voltages and electrodespacings are optimized for different ion beamconditions respectively. Beam properties comparisonof various simulation conditions are presented.

44

39Ar Enrichment System Based on a 2.45 GHz ECR Ion Source

Zehua Jia1 ; Xing FangNone ; Yuhui GuoNone ; Qiang HuNone ; Yunjie LiNone ; Liangting Sun2 ; Qi WuNone ; Yao YangNone; Taixin ZhanNone ; JingQuan ZhangNone ; Jiang WeiNone ; Zhengtian LuNone ; Yuguo LiuNone

1 IMP/CAS, Lanzhou2 Institute of Modern Physics, CAS


Aimed at improving the ATTA’s (Atom Trap TraceAnalysis) dating efficiency with 39Ar radioactiveisotope, an isotope enrichment system has beendeveloped at IMP (Institute of Modern Physics) toincrease the abundance of 39Ar in the incidentsample gas. In this enrichment system, a 2.45 GHzECR ion source was designed to ionize sample gasand produce isotopes beams with several mA, andthe isotopes beam is transported and separated inthe separation beam line, which is consisted of twoquadrupoles and an analysis magnet. The separatedisotopes are collected by a rotated aluminum foiltarget. According to the recent cross-checked resultswith ATTA, high enrichment factor of 39Ar isotopehas been successfully reached. This paper will give ageneral introduction to the platform setup. Theisotope enrichment efficiency is the critical issue forsuch a platform and will be specially discussed.

45

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Conceptual Design of an Electrostatic Trap for High IntensityPulsed BeamWei Huang1 ; Hongwei ZhaoNone ; Liangting Sun2 ; Daniel Xie3

1 Institute of Modern Physics2 Institute of Modern Physics, CAS3 LBNL, Berkeley, California


Highly charged ion sources play an important role inthe advancement of heavy ion acceleratorsworldwide. The beam requirements of highly chargedheavy ions from new accelerators have driven theperformance of ion sources to their limits andbeyond. In parallel to developing new technologies toenhance the performance of ECR ion source, thispaper presents a conceptual design of an ion trapaiming to convert a cw ion beam into a short beampulse with high compression ratios. With an electrongun, a solenoid and a set of drift tubes, the injectedions will be trapped radially and axially. Bymanipulating the potential of drift tubes, ions can beaccumulated with multiple injections and extracted ata fast or slow scheme. This paper presents thesimulation and design results of this ion trapprototype.

46

Numerical Simulations of Plasma Dynamics in ECRIS Afterglow

Li Lei1 ; Jibo LiNone ; Xiaolin JinNone

1 University of Electronic Science and Technology of China, Chengdu

Plasma dynamics in the afterglow of ECRIS has beenstudied through the Particle-in-cell (PIC) simulations.A full 3D implicit electrostatic PIC code wasdeveloped to meet the needs of ECRIS simulationsand to study the characteristics of the ECR plasmaduring the afterglow. The initial plasma parameters atthe simulation start-up were assumed by referring tothe experimental diagnostics of the ECRISs from IMP,Lanzhou. The dynamics of electrons and ions in thepresence of the external magnetic field and at theabsence of the microwave energy were simulated tostudy the mechanism of afterglow. Through theabundant diagnostics of the 3D PIC simulation, someECR plasma features during afterglow including theplasma potential and electron energy distributionscould be obtained and analyzed. The goal was todetermine the important evolutions that contribute tothe afterglow and thus to have a clearerunderstanding of ECRIS afterglow mode.

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47

Production of Metal Ion Beams From ECR Ion SourcesAndrey Bondarchenko1 ; Sergey Bogomolov1 ; Aleksander LebedevNone ; Vladimir LoginovNone ; Vladimir Mironov2; Dmitry PugachevNone ; Madi AbdigaliyevNone ; Igor IvanovNone ; Mikhail KoloberdinNone ; Alisher KurakhmedovNone; Daulet MustafinNone ; Yernaz Kajratovich SambayevNone ; Maxim ZdorovetsNone

1 JINR2 Joint Institute for Nuclear Research, Dubna, Moscow Region, 141980 Russia


The work describes the preparation of metal ionbeams from ECR ion sources by the MIVOC (MetalIons from Volatile Compounds) method. The methodis based on the use of volatile metal compoundshaving high vapor pressure at room temperature: forexample, Ni(C5H5)2, (CH3)5C5Ti(CH3)3 and severalothers. Using this method, intense beams ofchromium, titanium, iron, and other ions wereobtained at the U-400 FLNR JINR and DC-60cyclotrons (Astana branch of the INP, Alma-Ata,Kazakhstan Republic).

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Present Status of HIMAC ECR Ion SourcesMasayuki Muramatsu1 ; Atsushi KitagawaNone ; Fumihisa OuchiNone ; Toshinobu SasanoNone ; Tadahiro ShiraishiNone; Taku SuzukiNone ; Katsuyuki TakahashiNone ; Yoshiyuki IwataNone

1 QST-NIRS, Chiba

High-energy carbon-ion radiotherapy is being carriedout at Heavy Ion Medical Accelerator in Chiba(HIMAC). Over 12000 cancer patients have beentreated with carbon beams having energies ofbetween 56-430 MeV/u since 1994. There are twoinjectors in the HIMAC for medical and experimentaluse. First injector consists of two ECR ion sources andone PIG ion source, the RFQ linac and the DTL.Usually, this injector suppling the carbon ion forcancer therapy and various ion such as H, He, Fe, Xeare accelerated for biological and physicalexperiment. The 10 GHz NIRS-ECR ion sourceproduce the carbon ion for cancer therapy. The 18GHz NIRS-HEC ion source produce He to Xe ions forexperimental use. Second injector consists of thecompact ECR ion source with all permanent magnet,the RFQ linac and the APF IH-DTL. This injectorsupplies the carbon ion for experimental use.Additionally, we tried production of the Indium andthe Tin ions by using the In(C5H5) and the Sn(i-C3H7)4 at the NIRS-HEC. Beam current of the115In20+ and 120Sn18+ were 90 and 15 micro A,respectively. Present status of ECR ion sources andsome development will be described.

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Attempt toDevelop a 2.45GHzMicrowaveDriven Source for PlasmaFlood GunShixiang PENG1 ; Jia-er ChenNone ; Bujian CuiNone ; Zhiyu GuoNone ; Yaoxiang JiangNone ; Kai LiNone ; Tenghao MaNone; Jiamei WenNone ; Wenbin WuNone ; Yuan XuNone ; Ailin ZhangNone ; Jingfeng ZhangNone ; Tao ZhangNone

1 PKU, Beijing


Plasma flood guns (PFGs) are widely used toneutralize wafer charge during the doping process inmodern ion implanters. Compared with traditional dcarc discharge with filament and RF discharge, themicrowave driven source that has long lifetime andhas no metallic contamination is regarded as apotential choice of PFG [1]. Attempt to develop alarge scale PFG based on 2.45 GHz microwave drivensources was launched at Peking University (PKU). Aprototype one is a miniaturized 2.45 GHz permanentmagnet electron cyclotron resonance (ECR) source toproduce point-like electron beam. In previousexperiments, more than 8 mA electron beam hasbeen extracted with a Φ6 mm extraction hole at aninput microwave power of 22 W with argon gas [2].Recently, studies are focusing on the possibility ofproducing of ribbon electron beams as PFG with2.45GHz microwave driven surface wave plasma(SWP) source. A cylindrical chamber surface waveplasma generator with a using cylindrical dielectricwaveguide and a 70 mm×3 mm extraction slit wasfabricated. The primary test results were obtained.More details of this PFGs will be discussed in thiswork.

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Role of the 1+BeamOpticsUpstream the SPIRAL1ChargeBreeder

Laurent Maunoury1 ; Samuel DamoyNone ; Mickael DuboisNone ; Romain FrigotNone ; Stephane HormigosNone ;Bertrand JacquotNone ; Omar KamalouNone

1 GANIL


The SPIRAL1 charge breeder (SP1CB) is underoperation. Radioactive ion beam (RIB) has alreadybeen delivered [1] to Physicist for experiments.Although charge breeding efficiencies demonstratedhigh performances for stable ion beams, thoseefficiencies regarding RIB are lower. The beam optics,prior to the injection of the 1+ ions into the SP1CB, isof prime importance [2] for getting such highefficiencies. Moreover, the intensities of theradioactive ion beams are so low, it is really difficultto tune the SP1CB. A stable beam having a close Bis required to find out the set of optic parameters

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preceding the tuning of the RIB. Hence, it has beendecided to focus our effort on that issue as to getcontrol of the 1+ beam optics leading to high chargebreeding efficiencies whatever the 1+ mass, energyand Target Ion Source System used (TISS). Beingaware that TISS’s provide ion beams with a specificenergy spread and knowing that the acceptanceenergy of the SP1CB is rather narrow; that parametermust play also a role in the charge breedingefficiency. This contribution will show the strategyundertaken to overcome that problem and the resultsalready obtained.

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LNLGANILLPSCCollaborationOnTheContaminantsReductionIn ECR Charge BreedersJulien ANGOT1 ; Maud BaylacNone ; Myriam Migliore2 ; Patrick SoleNone ; Thomas Thuillier3 ; Laurent Maunoury4 ;Alessio Galatà5

1 Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3, 38000 Grenoble, France2 CNRS-LPSC3 LPSC, Grenoble Cedex4 GANIL5 INFN-Legnaro National Laboratories


Contaminants reduction in Electron CyclotronResonance Charge Breeders (ECRCB) is a key pointfor the future experiments foreseen at LNL andGANIL Isotope Separation On Line (ISOL) facilities.According to the mass separator resolution setdownstream the ECRCB, the radioactive ion beamstudy can be challenged in case of low productionrate. An ongoing collaboration between LNL, LSPCand GANIL laboratories aims to improve the beampurity, acting on all the pollutant causes.Comparative experiments will be done at LPSC usingdifferent techniques, like covering the plasmachamber wall with liners in several material. Differentconfigurations of the ECRCB will also be tested, withthe enhancement of the efficiency and chargebreeding time parameters as additional objectives. Apresentation of this program is proposed togetherwith the effective upgrade of the LPSC 1+N+ testbench which goal was to improve the vacuum qualityand clean all the beam line devices.

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ECR3 Commissioning and Planning for C-14 Ion Beams at theArgonne Tandem Linac Accelerator SystemRobert Scott1 ; Richard Vondrasek1

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1 Argonne National Laboratory


The Electron Cyclotron Resonance Ion Source ECR3*has recently been commissioned at the ArgonneTandem Linac Accelerator System (ATLAS) atArgonne National Laboratory. While ECR3 can providemany of the stable ATLAS beams, its other intendedpurpose is the production of C-14 ion beams whichwere previously produced by a now-retired negativeion source. This paper will discuss the finalinstallation and commissioning of the ion source aswell as the preparations for running C-14. A stableC-13 ethylene gas was used as a surrogate todetermine the expected level of N-14 contaminationwhen running C-14 since they are inseparable atATLAS. We were also able to confirm consumptionrates and charge state efficiencies under differentC-13 running conditions in order to optimize theupcoming C-14 beam production.

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Improvement of theEfficiency of theTriumfCharge State Booster

Joseph Adegun1 ; Friedhelm Ames1 ; Oliver Kester1

1 TRIUMF


The Electron Cyclotron Resonance Ion Source is aversatile and reliable source to charge-breed rareisotopes in TRIUMF’s Isotopes Separation andAcceleration (ISAC) facility. Significant research workhas been done by different groups worldwide toimprove the efficiency and performance of the ECRISas a charge state booster. The most recent of theseresearch works is the implementation of the twofrequencyheating on an ECRIS. At the ISAC facilityof TRIUMF, a 14.5 GHz PHOENIX booster which hasbeen in operation since 2010 was recently upgradedto accommodate the two-frequency heating systemusing a single waveguide. The efficiency for chargebreeding into a single charge state, which depends onthe rare isotope that is being charge-bred, has beendetermined to be between 1 - 6 %. The CSB is beingupgraded to improve its charge breeding efficiency. Adetailed investigation of the effect of the twofrequencyheating technique on the intensity,emittance and the efficiency of the extracted beam ispresently being conducted.

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Studies of ECR Plasma Chamber Contamination With Acceler-ated Beams and Diamond Detectors

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Brian Roeder1 ; Juha Eerik ArjeNone ; Donald Philip MayNone ; Sherry Yennello2 ; Fred AbegglenNone ; George J.KimNone ; Gabriel TabacaruNone

1 Texas A&M University2 TAMU


While developing stable and re-accelerated rareisotope beams (RIB) for acceleration with the TAMUK500 cyclotron, a background of various stablebeams has been observed. It has been determinedthat this background is arising from alloys andcontamination in the components of our ECR ionsources, in particular, the aluminum alloy plasmachamber. We have developed a detector systembased on diamond detector telescopes that allows usto measure the composition of the beam afteracceleration with the K500 cyclotron at TAMU. Usingthis technique, we have been able to develop ionsource and cyclotron tuning methods to minimize thestable beam background and maximize the stablebeams of interest and/or the RIBs. We also endeavorto reduce the stable beam background from the ECRion sources using techniques such as pure aluminumliners. In my presentation, I plan to show ouraccelerated beam detection setup with diamonddetectors. I also plan to present about thebackground we have measured with this setup fromthe ECRIS components, in particular, the plasmachamber. Finally, I will comment on our efforts toreduce this background.

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Opening Session

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Status Report and New Development

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Status Report and New Development II

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Plasma Investigations

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Poster/ Short Presentation

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Open Discussion

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Adjourn

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Announcements

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Plasma Physics and Techniques

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Plasma Physics and Techniques II

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Plasma Physics and Techniques II

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Modelisation, Simulation

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Poster/ Short Presentation

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Electron Cyclotron Emission Imaging of Electron Cyclotron Res-onance Ion Source PlasmasLawrence Ethan Henderson1 ; Henry ClarkNone ; Carl GagliardiNone ; Donald Philip MayNone

1 Texas A&M University, College Station, Texas

A new imaging system for Electron CyclotronResonance Ion Sources (ECRIS) has been designedand is being built. This K- and Ka-band camera willextract localized measurements of absolute energyand relative number density for ECRIS plasmaelectrons by imaging their Electron CyclotronEmission (ECE) spectra, as the frequency, shape, andstrength of the ECE harmonics correlate directly withthe local magnetic field, electron energy, and plasmadensity. The design of the overall quasi-opticalsystem will be presented, including novel ceramicoptics for the radial viewports of the CyclotronInstitute’s ECRIS and metamaterial mirrors withelectronically controllable reflectivity. Spatialresolution sufficient to distinguish important plasmaregions and temporal resolution sufficient to studydynamic plasma processes is expected.

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24thInternationalWorkshop onECRIonSources(ECRIS’20) ·...

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