The 18th International Conference on Ion Sources

Asia/Shanghai
Lanzhou

Lanzhou

No. 1 Beibinhe East Road, Chengguan District, Lanzhou
Zhao Hongwei (IMP)
    • 08:30 09:00
      Registration
    • 09:00 09:30
      Opening Ceremony
    • 09:30 10:00
      Keynote Speaker: Wenlong Zhan (CAS)
    • 10:00 10:30
      Review of high intensity ion source development and operation for worldwide nuclear science facility 30m

      The Electron Cyclotron Ion Source (ECRIS) has transformed the nuclear physics research field over the last 40+ years. Today the performance of ECRIS sources are the first parameter that defines the design of new facilities and the performance of existing facilities. In this talk, I will review the current ‘state of the art’ performance capabilities for ECR ion sources and how those present capabilities form the primary design criteria for new facilities and set the limiting performance for existing facilities.

      Speaker: Dr Richard Pardo
    • 10:30 10:50
      Conference Photo
    • 10:50 11:20
      Coffee Break
    • 11:20 11:40
      Estimating Ion Confinement Times from Beam Current Transients in Conventional and Charge Breeder ECRIS 20m

      High-precision measurements [1] of the Doppler broadening of ion spectral lines have indicated, that ions in an ECRIS plasma may obtain much higher temperatures than is conventionally believed, i.e. on the order of 10 eV. The temperature is also observed to be charge state dependent. The anomalous temperatures could plausibly be explained by assuming the electrostatic confinement of ions in a potential well within the plasma potential, caused by accumulated hot electrons in the plasma core [2, 3]. In this confinement scheme, the ions would obtain long cumulative confinement times, which would allow them to be heated in collisions with the cold electron population.

      In the work presented herein, the ion confinement time is probed using a transient method similar to that employed in [4, 5]: Material injection into a buffer plasma is pulsed, and the extracted, decaying beam current transients are analyzed to obtain an estimate for the ion confinement time. The method is applied both in an ECR charge breeder source where material injection is realized by direct 1+ injection of potassium, and in a conventional ECRIS using sputtering of copper into various buffer gases (O, He, Ar). The transient equation used for the data analysis is derived from the ion balance equation, and the validity of the assumptions made in its derivation are evaluated. The measurements from the two experimental campaigns analyzed for this work yielded mutually corroborative results: The confinement time is estimated to be on the order of tens of milliseconds for Cu and K ions at charge to mass ratios between 0.15 and 0.27, with higher charge states corresponding to longer confinement times.

      The long confinement times support the notion of electron-ion interaction as a source of the anomalous ion temperatures, and a qualitative model based on the electrostatic confinement and electron-drag heating is proposed to connect the ion temperatures to the confinement times. Understanding the confinement times of highly charged ions is important fundamentally, but also for the practical purpose of developing radioactive ion beams, which depend not only on fast and efficient ionization, but also on short ion confinement times, to prohibit the decay of the radioactive isotopes during the charge breeding process.

      Speaker: Mr Miha Marttinen (University of Jyväskylä)
    • 11:40 12:00
      Effects of magnetic configuration on hot electrons in SECRAL-II plasma 20m

      To investigate the hot electrons population in highly charged electron cyclotron resonance ion source (ECRIS), the axial emitted bremsstrahlung spectra, along with microwave signal emitted from the ECRIS plasma are measured on SECRAL-II (Superconducting ECR ion source with Advanced design in Lanzhou No. II) ion source. The evolution of the hot electrons spectral temperature, Ts, is studied through the variation of magnetic configuration. The experimental results have shown that when the ratio of the minimum field to the resonance field (i.e. Bmin /Becr) is less than 0.75~0.80, there is a linear dependence of the spectral temperature on the ratio of Bmin /Becr, above this threshold Ts saturates and electron cyclotron instability appears simultaneously. This phenomenon may be due to the fact that the spectral temperature Ts provides an indication of the temperature of the hot electrons, significant losses of the hot and warm electrons caused by electron cyclotron instability will lead to a saturation of Ts. In addition, this investigation has also shown that Ts decreases with the increase of the gradient at the resonance zone at low mirror ratio and is insensitive to the gradient at high mirror ratio when Bmin is constant.

      Speaker: Jibo Li
    • 12:00 12:20
      Evaluation method of plasma instability in laser ion source using solenoid 20m

      A laser ion source can provide stable intense heavy ion beams with relatively simple structure. Recently, solenoid confinement technique was developed and applied to the operating laser ion sources. By introducing solenoid, supplied ion beam current can be enhanced and adjusted for the applications. However, it is known that the expanding laser plasma confined by a solenoid filed becomes unstable in a certain magnetic field region. To investigate the unstable condition further, it is essential to quantify the instability. In this study, we propose the most appropriate method to evaluate plasma instability. The validity was evaluated by comparing five methods, variation of maximum value, variation of integral value, variation of half width, variation of half value width divided by maximum value, integral value of difference from average waveform. The detailed comparison discussion will be given at the presentation.

      Speaker: Takahiro Karino
    • 12:20 13:50
      Lunch Break
    • 14:00 14:30
      Measurements and Simulations of the Energy Distribution of Electrons Lost from the Minimum B-field 30m

      Further progress in the development of ECR ion sources (ECRIS) requires a deeper understanding of underlying physics. One of the topics that remains little studied, though being crucial for the confinement of the plasma and performance of the ion source, is the electron energy distribution (EED). A well-developed technique of measuring the EED of electrons escaping axially from a magnetically confined plasma of an ECRIS is reported. The majority of the experimental data were recorded in pulsed and CW discharges with a room-temperature 14 GHz ECRIS at the JYFL accelerator laboratory. It was discovered that for 14 GHz source the EED is strongly non-Maxwellian in the range of 5–250 keV and exhibits several local maxima below 20 keV energy. It was observed that the most influential ion source operating parameter on the EED is the magnetic field strength, which affected the EED predominantly at energies less than 100 keV. The effects of the microwave power and frequency on the EED were found to be less significant. The latter measurements were focused on distinguishing between the EED in stable plasma and the one perturbed with kinetic instabilities. It was found that nonlinear phenomena alter the energy distribution of the lost electrons noticeably. It has been shown earlier that the two-frequency plasma heating mode, being widely used, boosts the ECRIS performance presumably thanks to suppression of kinetic instabilities. We report the observed changes in EED of the escaping electrons introduced by the secondary frequency in different regimes, including the one with the secondary frequency being below the cold ECR in the magnetic trap. Discussion on the suppression mechanism of kinetic instabilities by means of applying the secondary frequency heating and the role of RF pitch angle scattering is presented along with the comparison of experimentally obtained EED to the simulated one with the use of NAM-ECRIS PIC code.

      Speaker: Dr Ivan Izotov (Institute of Applied Physics of Russian Academy of Sciences)
    • 14:30 15:00
      Self-Consistent Modeling of Beam-Plasma Interaction in the Charge Breeding Optimization Process 30m

      The slowing down and capture by a plasma of externally injected 1+ ions, as a consequence of very frequent elastic Coulomb collisions, is the main mechanism involved in the charge breeding process based on Electron Cyclotron Resonance Ion Sources. The INFN ion source group has been undertaking an intense activity on numerical simulations of the beam-plasma interaction, developing a code that has been proving to be very effective in reproducing several experimental results of charge breeding of light and heavy ions. This contribution will present the progress made in the development of the numerical code, focusing the attention on the latest simulations of charge breeding of Rb1+ ions employing a self-consistent plasma target model. The effect of the real plasmoid/halo structure on the capture process will be underlined, as well as the influence of different plasma excitation frequencies.

      Speaker: Dr Alessio Galatà (INFN-Legnaro National Laboratories)
    • 15:00 15:20
      Multi-diagnostics setup as a tool to overcome the limits of compact ion sources 20m

      The development of plasma diagnostics devoted to compact ion sources is being one of the main efforts of INFN-LNS ion source group for a decade. Indeed, the use of the brute force can lead to improvements in ion sources’ performances only if accompanied by a proper understanding of the plasma physics processes within the ion source. The key goal of plasma diagnostics in compact ion sources is the volumetric knowledge of the electron energy distribution function (EEDF) and the on-line evaluation of the plasma composition. This information will allow tuning EEDF to maximize the generation of the desired ion. Moreover, development of time resolved diagnostics has given precious information about the strategy for decreasing the beam ripple and increasing the operability domain of ion sources.
      The paper will introduce the most relevant diagnostics developed in the last ten years at INFN-LNS (optical emission spectroscopy, volume and space resolved X-ray diagnostics, RF and Langmuir probe diagnostics, interfero-polarimetric diagnostics) together with the main experimental results they have permitted to attain.
      Particular relevance will be also given to the perspectives and next goals of plasma diagnostics’applications.

      Speaker: Giuseppe Castro (INFN-LNS Via S. Sofia 62, 95123 Catania (Italy))
    • 15:20 15:40
      Particle-in-cell simulation of transport and energy deposition of intense proton beams in solid-density material 20m

      A complete particle-in-cell (PIC) simulation has, for the first time, been performed for the transport and energy deposition of an intense proton beam within a solid. In particular, for close interactions, we developed a novel Monte-Carlo binary collision model that takes into account all interactions between the incident protons and matter, e.g. proton-nuclei, proton-bound electron and proton-free electron. This includes especially also a Monte-Carlo model for the collisional ionization and electron-ion recombination as well as the depression of the ionization potential by surrounding charged particles. Moreover, we take into account collective electromagnetic effects by solving reduced Maxwell Equations. For intense proton beams, the collective electromagnetic effects ensure localized energy deposition by collimating proton beams, which would otherwise be deflected by the collisions with nucleus. This simulation model enables kinetic investigation of charged particle transport in high energy density plasmas.

      Speaker: Dr Dong Wu (Zhejiang University)
    • 15:40 16:00
      Upper Hybrid Resonance Heating Experiments on Electron Cyclotron Resonance Ion Source 20m

      We have been considered accessibility condition of electromagnetic and electrostatic waves propagating in ECR ion source (ECRIS) plasma, and then investigated their correspondence relationships with production of multicharged ions. It has been clarified that there exits efficient configuration of ECR zones for producing multicharged ion beams, and then has been suggested that new resonance, i.e. upper hybrid resonances (UHR), must have occurred.[1] We have been promoting new advanced experiments inducing actively these additional effects for enhanced furthermore multicharged ion beams with launching extra-ordinary (X) mode waves. Initially we had already conducted to applying 9GHz X-mode microwaves to 2.45GHz ECRIS, and it had been observed enhancements of higher energy tails of electron energy distributions function measured by the probe methods.[2] Next we have been trying similar experiments with 4-6GHz X-mode microwaves,[3] and we have succeeded in enhancing production of multicharged ions by launching these bands X-mode microwaves. Furthermore, at the same time we have observed sharp increases of electron energy distribution functions in ECRIS plasma by means of probe methods. It have been concluded that the UHR must have occurred by applying multiplex microwaves with their frequencies away from those for ECR in ECRIS. In this paper we will describe brief theoretical background and these new experimental results.

      References and Acknowledgment
      [1] Y. Kato, K. Yano, T. Nishiokada, et.al, Review of Scientific Instruments, 87(2016)02A710-1-4.
      [2] T. Nishiokada, T. Nagaya, S. Hagino, et.al, Review of Scientific Instruments, 87(2016)02A714-1-3.
      [3] Y. Kato, T. Nishiokada, T. Nagaya, et.al, AIP Conference Proceedings 2011, 020005 (2018)
      The authors would like to thank Professor T. Asaji, National Institute of Technology, Toyama College, for preparations of additional microwave sources to be available in these works.

      Speaker: Yushi Kato (Osaka Univ.)
    • 16:00 16:20
      Measurement of the Energy Distribution of Electrons Escaping Confinement from an Electron Cyclotron Resonance Ion Source 20m

      The production of high charge state ions in electron cyclotron resonance ion sources (ECRIS) is dependent on the electron energy distribution (EED) within the source plasma. In order to better understand the EED a measurement of electrons escaping axially from an ECRIS device has taken place at the National Superconducting Cyclotron Laboratory (NSCL). Electrons were measured escaping from the Superconducting Source for Ions (SuSI), driven at 18 GHz. Dependencies of the observed EED on the confining magnetic field strength, injected microwave power, and neutral gas pressure were measured. Measurements of the axial bremsstrahlung spectrum were simultaneously measured to provide a direct comparison between both techniques. Results showed a large peak of electrons in the 600-1000 keV energy range. Calculations of the average electron energy and bremsstrahlung spectral temperature as a function of varying plasma parameters are also reported.

      Speaker: Mr Bryan Isherwood (Michigan State University/NSCL/FRIB)
    • 16:20 17:50
      Coffee Break: Poster Session - MonP C01, C06, C10
    • 08:30 09:00
      Overview of High Intensity Ion Source Development in the Past 20 Years at IMP 30m

      In the past 20 years, obvious progress has been made with the IMP ion accelerator development in terms of high intensity, high energy and high power machines. We still foresee the facilities to be built in the near future, for instance HIAF (High Intensity heavy ion Accelerator Facility) and CiADS (China initiative ADS), and so on, which have strong demands of high intensity ion beams of H~U. High intensity ion source paves the way for the development of future ion accelerators. Therefore, continuous research and development work has been made at IMP to improve ion source performance by means of new machine developments and ion source physics investigations. For intense mono-charged ion beams, 2.45 GHz ion sources have been developed together with the low energy transmission lines. For intense CW/DC multiply charged ion beams production, high performance ECR ion sources have been developed with the operation frequencies of 14.5~45 GHz. As very high intensity pulsed ion beams could be used for synchrotron injection, especially of those of very refractory metals, laser ion source has also been introduced to IMP, and got remarkable progress in the past years with regards to ion beam intensities, charge states, and beam stabilities. This paper will give an overview of the high intensity ion source development at IMP, especially on the recent progresses and new results.

      Speaker: Liangting Sun (Institute of Modern Physics, CAS)
    • 09:00 09:30
      EBIS Development at RHIC for the BNL Heavy Ion Program and the EIC 30m

      The Extended EBIS will provide 2.1E9 Au32+/pulse at the Booster ring entrance, a 40-50% intensity upgrade compared with the existing RhicEBIS at BNL. The axial magnetic field for an extended ion trap is achieved through the use of two closely coupled 5T superconducting solenoids, reinforced to withstand the axial forces between the modules. A 6A electron beam has been successfully propagated through the prototype of a novel “external” drift tube structure within one 5T superconducting solenoid. The second solenoid and corresponding drift tube structure has been added and testing is underway to establish 5-6A electron beam propagation through the extended two solenoid system. A highly efficient gas injection system has been designed, primarily for the injection of polarized 3He and other light gases. Beams of 3He2+ with intensity up to 2.5E11 ions per pulse and 70% polarization will be produced for RHIC and the future Electron Ion collider. Results of the present tests and plans for the Extended EBIS development will be discussed.

      Speaker: Edward Beebe (BNL)
    • 09:30 09:50
      Production of intense metal ion beam with RIKEN 28 GHz SC-ECRIS 20m

      To produce intense metal ion beams (e.g. Ti13+, V12+,13+, U35+ ) for super-heavy element search and RIBF experiments at RIKEN, we tried to optimize the RIKEN 28 GHz SC-ECRIS performance. We systematically measured the beam intensity of various heavy ions as a function of Binj, Br and Bext with 14, 18 and 28 GHz microwaves for various heavy ions. In these experiments, we observed that (1) optimum Binj>1.6~2 Bext, (2) optimum Br>1.2~1.4 Bext and (3) optimum Bext is dependent on the charge state.
      Using this systematics, we obtained ~400emicroA of V13+ at low RF power of ~2kW and very low magnetic field (Bext~1.4 T with 28 GHz). For long term operation (one month), we successfully produced very stable beam of 100~200 e micro A of V13+ ion. Based on the systematics, we also produced ~225 e micro A of U33+ ion beam and ~200 e micro A of U35+ ion beam at only 2.2~2.6 kW of RF power.
      In this contribution, we discuss the mechanism to obtain these systematics using simple model calculation. And we report the experimental results and how to produce intense metal ion (Ti, V, and U ions) beams in detail.

      Speaker: takahide Nakagawa (RIKEN)
    • 09:50 10:10
      Production of Intense Uranium Beams with Inductive Heating Oven at Institute of Modern Physics 20m

      HIAF (High Intensity heavy ion Accelerator Facility) is a new accelerator complex under construction at Institute of Modern Physics. As the main injector of this project, the high-charge-state ECR ion source needs to provide intense uranium beams, such as 700 euA of U35+, and so on. This requires the performance of metal ovens to be further improved so that the crucible can operate at ultra-high temperature for a long time without damage in high magnetic field (>3 T). In order to meet these requirements, an inductive oven with special thermal shielding and support has been developed in the past two years. The off-line test result has shown that this oven can reach up to 2000 degree C with ~1.2 kW of heating power. After 5 days’ continous running on SECRAL-II platform, the tantalum crucible survived. In this contribution, we will discuss the structure of this inductive oven and analyze the test results as well.

      Speaker: Wang Lu (Institute of Modern Physics)
    • 10:10 10:30
      Stable Short-pulse Ion Beam Production with the Laser Ion Source at IMP 20m

      To extend the long-term operation capability of the laser ion source, a new manipulating system and the corresponding control system has been developed at the Institute of Modern Physics, into which a rotating axis was integrated besides the existing X, Y, and Z axes. With the new developed manipulating system, the laser ion source can be operated with cylindrical targets, which is meaningful for the practical application of the laser ion source because the surface area of a cylindrical target is much larger compared with a flat one. And with the help of the control system, the laser ion source can be operated in the continuous mode with the repetition rate below 5 Hz, which is limited by the laser and vacuum system. The pulse-to-pulse repeatability and over-thirty-hour stability of the carbon ion beam delivered by the laser ion source will be presented in this paper.

      Speaker: Dr Huanyu Zhao (Institute of Modern Physics, Chinese Academy of Sciences)
    • 10:30 11:00
      Coffee Break
    • 11:00 11:30
      Charge breeding at Ganil: improvements, results and comparison with the other facilities 30m

      The 1+/n+ method, based on an ECRIS charge breeder originally developed at the LPSC laboratory, is now implemented at GANIL for the production of Radioactive Ion Beams (RIBs). Prior to its installation in the middle of the low energy beam line of the SPIRAL1 facility, the 1+/n+ system charge breeder has been modified based on the experiments performed on the CARIBU Facility at Argone National Laboratory. Later, it has been tested at the 1+/n+ LPSC test bench to validate its operation performances. Charge breeding efficiencies as well as charge breeding times have been measured for noble gases and alkali elements. The commissioning phase started at GANIL in the second semester of 2017. It has consisted of a stepwise process to test the upgrade of the SPIRAL1 facility from simple validation (operation of Charge Breeder (CB) as a stand-alone source) up to the production of the first 1+/n+ radioactive ion beam. Thus, this year, a 38mK / 38K radioactive ion beam has been successfully delivered to a physics experiment over a period of 1 week. The yields on the physics target were in the range of 2-4.106pps at 9 MeV/u. The target ion source system (TISS) was made of a FEBIAD ion source connected to a hot graphite target. This is the first time a radioactive ion beam is accelerated with a cyclotron with the 1+/n+ method. Moreover, a production test with the FEBIAD TISS has confirmed the yields measured previously, which validates the extension of the GANIL/SPIRAL1 catalog for a number of isotopes.

      In parallel R&D is being performed on new TISSs (e.g. a fast release one, using surface ionization source). Targets are also a subject of ongoing R&D for yield and release time optimization.

      This contribution will present the new acceleration scheme of the SPIRAL1 facility, which largely extends the palette of RIBs available for nuclear physicists. It will be compared to the one used at similar ISOL facilities. This facility is more than a simple ISOL facility and an overview of the new potentials offered by the upgraded installation will be also discussed.

      Speaker: Laurent Maunoury (GANIL)
    • 11:30 12:00
      EBIS/T Charge Breeders at RIB Facilities 30m

      At accelerator facilities, charge breeders convert ion beams of low charge states into multiply charged ion beams to increase (or boost) the energy of beams. A field of application that has grown over the past decades is charge breeding of rare-isotope beams (RIB). Several post-accelerators at RIB facilities currently in operation and under construction employs electron-beam ion sources and traps (EBIS/T's) as charge breeders. Compared with other charge breeding techniques, EBIS/T's have many advantages: high efficiency, fast and variable breeding times, small beam emittances, and high beam purity. This publication reviews the use of EBIS/T charge breeders of RIB with an emphasis on their use for post-acceleration.

      Speaker: Alain Lapierre (Michigan State University)
    • 12:00 12:20
      The study of 1+ ion beam interaction in an ECR charge breeder ion source plasmas using Monte-Carlo Charge Breeding Code (MCBC) 20m

      As a part of SPIRAL1 upgrade, experimental studies were carried out to understand the ion transport through the SP1 ECR charge breeder and to investigate the physical mechanisms involved in charge breeding process [1]. Numerical simulations were performed using SIMION 3D to reproduce the trends of low charge states (1+ and 2+) experimental results (charge breeding efficiency versus ∆V curves) by transporting the 1+ ion beam through a potential map that reflects the presence of the ECR plasma (without collisions) [1]. The simulations results showed good agreement with the experiments and revealed the role of Coulomb collisions in the charge breeding process leading to a necessary detailed analysis using a full six-dimensional (6D) phase space Monte-Carlo Charge Breeding code (MCBC) [2, 3].

      The simulation code models Coulomb collisions of the injected 1+ ion beam in an ECR plasma and atomic processes which includes ionization and charge exchange. The background ECR plasma has been modeled by implementing a simplified plasma model scheme, proposed in the previous charge breeding simulation studies [4, 5]. The charge breeding simulations were performed for three experimental cases (interaction of Na1+ with a helium plasma, K1+ with a helium plasma and K1+ with an oxygen plasma). The model finally able to reproduce the low charge state (1+ and 2+) experimental trends by varying each plasma parameter (plasma density, ion temperature and electron temperature) independently. Finally, the estimated plasma parameters obtained from each case are presented and the reasons for the difference in charge breeding efficiencies between Na and K species are discussed.

      References
      [1] A. Annaluru et al., “1+/N+ method: numerical simulation studies and experimental measurements on the SPIRAL1 ECR Charge Breeder”. Journal of Instrumentation. 14. C01002-C01002. 10.1088/1748-0221/14/01/C01002.

      [2] J. S. Kim, L. Zhao, B. P. Cluggish and Richard Pardo, "Ion beam capture and charge breeding in electron cyclotron resonance ion source plasmas", Rev. Sci. Instrum., 78, 103503 (2007).

      [3] L. Zhao, B. P. Cluggish, J. K. Kim, R. C. Pardo and R. C. Vondrasek, "Simulation of charge breeding of rubidium using Monte Carlo charge breeding code and generalized ECRIS model", Rev. Sci. Instrum., 81, 02A304 (2010).

      [4] A. Galata, D. Mascali, L. Neri and L. Celona, "A new numerical description of the interaction of an ion beam with a magnetized plasma in an ECR based charge breeding device", Plasma Sources Science and Technology. 25. 10.1088/0963-0252/25/4/045007.

      [5] V. Mironov, S. Bogomolov, A. Bondarchenko, A. Efremov, V. Loginov, "Simulations of charge-breeding processes in ECRIS", AIP Conference Proceedings 2011, 070003 (2018).

      Speaker: Arun Annaluru (Grand Accélérateur National d’Ions Lourds)
    • 12:20 13:50
      Lunch Break
    • 14:00 14:30
      Selectable High Intensity H+/H2+/H3+ Beam with a 2.45 GHz ECR Ion Source 30m

      At Peking University (PKU), experimental research as well as theoretical study on how to produce high intense H+, H2+ or H3+ domain ion beams with a compact permanent magnet 2.45 GHz ECR ion source (PMECRIS) have been continuously carried out in the past decades.
      With a so-called standard PKU PMECRIS, a 130 mA@50 keV pulsed (100 Hz/1 ms) H+ beam with H+ faction of 90% was obtained in 2016. A 50 mA@50 keV CW H+ beam with this PMECRIS has been run continuously for 300 hours without any beam-off, spark, beam drop. It proved that the availability and reliability of this standard PKU PMECRIS is nearly 100%. The root-mean-square (RMS) emittance of 50mA@50keV CW H+ is about 0.19 π.mm.mrad. Investigation on high intensity H2+ and H3+ ion domain beam generation has been also carried out since 10 years ago. In 2013, 40 mA H2+ and 20 mA H3+ beams were obtained with a source named as PKU PMECR II. The corresponding fractions of H2+ ion and H3+ ion within the total extracted beam are 47.7% and 43.2% respectively.
      Recently, more attentions were paid on the understanding of hydrogen plasma to improve the performance of 2.45 GHz ECR hydrogen ion sources. Some hydrogen plasma parameters were acquired with method of optical emission spectroscopy (OES) in a 2.45 GHz ECR ion source. Meanwhile, a numerical model based on the particle population balance equations was developed for quantitative comprehension of electron cyclotron heated (ECH) hydrogen plasma. On these basis, working parameters of the source, wall material of the discharge chamber, and other factors have been optimized according to the calculated results. With these improvements, more than 42 mA H2+ ion beam with species fraction of 54% and 20 mA H3+ ion beam with species fraction of 55% were obtained with PKU PMECR II [10]. Recently, a miniaturized ECR ion source was developed and a 52 mA hydrogen beam was extracted. Under the guidance of the model developed here on the ion species fraction selection, this miniaturized ECR ion source can easily produce either H+ or H2+ or H3+ domain beam. Measurement results with the miniaturized ECR ion source show that under different working parameters H+, H2+ and H3+ fraction can reach up to 88%, 80% and 82%, respectively.

      Speaker: Shixiang PENG
    • 14:30 15:00
      J-PARC Hˉ Ion Source and Space-Charge Neutralized LEBT for 100 mA High Energy and High Duty Factor LINACs 30m

      The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven Hˉ ion source has successfully operated with a 57 mA & 50 keV beam for a 50 mA beam at the exit of the J-PARC 400 MeV LINAC for about one year from October 2018. It is also producing a 72 mA beam for the J-PARC LINAC 60 mA operation studies. The world's highest class intensity beam with transverse emittances suitable for RFQs of high energy Hˉ ion LINACs is produced with several unique measures, such as, slight water molecules addition into the hydrogen plasma, the low temperature (about 70 ºC) operation of the 45º-tapered plasma electrode with a 16-mm thickness, a 30-MHz CW plasma igniter, the macro-pulse chopping with a rapid rising time by the Hˉ ion energy modulation being below the RFQ longitudinal acceptance, and so on [1, 2]. Its stable 8 hours 100 mA beam operation was demonstrated in a test stand by increasing the terminal voltage from 50 kV to 62 kV [2]. In this paper, these measures essential for a 100 mA operation are reviewed and explained. The recent transverse emittance improvements with the shortest beam extractor are also presented. The horizontal/vertical 95 % beam normalized rms emittances of a 100 mA & 62 keV beam were improved by about 8 % form 0.262/0.3 ·mm·mrad to 0.242/0.273 ·mm·mrad with the thinnest extraction electrode (1.5 mm thinner) and the ground electrode 1.5 mm extended to upper stream. The emittances of a 66 mA & 50 keV beam and a 80 mA & 56 keV beam ere also improved about 8 % with the shortest beam extractor. About 94 % of each beam with the intensity of 66, 80 or 100 mA is distributed in the transverse phase planes inside of the normalized 1.5 ·mm·mrad ellipse, the water bag distribution in which is commonly used to design RFQs of high energy LINACs.
      References and Acknowledgment
      [1] A. Ueno , K. Ohkoshi, K. Ikegami, A. Takagi, K. Shinto, and H. Oguri, AIP Conference Proceedings 2052, 050003
      (2018).
      [2] K. Shinto, K. Ohkoshi, T. Shibata, K. Nanmo, K. Ikegami, A. Takagi, Y. Namekawa, A. Ueno, and H. Oguri, AIP
      Conference Proceedings 2052, 050002 (2018).
      [3] A. Ueno, New J. Phys., 19, 015004 (2017).

      Speaker: Dr Akira Ueno (J-PARC)
    • 15:00 15:20
      Commissioning of High Current H+/D+ ion beams for the Linear IFMIF Prototype Accelerator (LIPAc) 20m

      The Linear IFMIF (International Fusion Materials Irradiation Facility) Prototype Accelerator (LIPAc) is aiming at demonstration of the low energy section of 40 MeV/125 mA IFMIF deuteron accelerator up to 9 MeV with a full beam current in continuous wave (CW). For such high-power beam, the LIPAc injector is required to produce a 100 keV D+ beam with 140 mA. The injector is composed of the ECR ion source based on the CEA-Saclay SILHI source and a Low Energy Beam Transport (LEBT) line. The capability of the injector to produce 100 keV/140 mA D+ beam with emittance of 0.25 π mm mrad has already been demonstrated by 2017. The H+ beam with half energy and half current with respect to the nominal D+ beam is also used at the initial phase of the beam commissioning of the 175 MHz, 5 MeV Radio Frequency Quadrupole (RFQ). In 2019, the commissioning of the RFQ to demonstrate the D+ beam acceleration at low duty cycle (0.1%) is being implemented. This paper describes the latest results obtained through the efforts to characterize the pulsed D+ beam as well as H+ beam extracted from injector. The progress of demonstration of high current D+ beam acceleration will be also presented.

      Speaker: Tomoya Akagi (National Institutes for Quantum and Radiological Science and Technology)
    • 15:20 15:40
      C-PIMS based on a 2.45 GHz microwave ion source and a floating potential charge exchange cell 20m

      Carbon positive-ion mass spectrometry (C-PIMS) is a two stage mass spectrometer by producing high charge state carbon ions (C2+/C3+) directly in the ion source to eliminated molecular interferences and by converting the beam to negative ions in a charge exchange cell to eliminate 14N interference. Results obtained by M. Hotchkis[1] based on 7 GHz ECR ion source has proved that PIMS is an effective method for the detection of radiocarbon at low levels. Now we propose a new conceptual design based on a 2.45 GHz microwave ion source and a floating potential charge exchange cell (CXC). Preliminary test results have proved that the 2.45 GHz microwave ion source can produce up to 40 μA@40 keV C2+ beam. Very basic investigation of CXC design is also launched. Details will be presented.

      [1] Michael Hotchkis, Tao Wei, Radiocarbon detection by ion charge exchange mass spectrometry. Nuclear Instruments and Methods in Physics Research B 259, 158-164 (2007).

      Speaker: Mr Wenbin Wu
    • 15:40 16:00
      Commissioning of the RF H- source in CSNS 20m

      China Spallation Neutron Source (CSNS) has started to serve the users since March of 2018. To upgrade the beam power to 500 kW and improve the performance of ion source, an RF coupled H$^-$ source is under development. The source has a Si$_3$N$_4$ ceramic plasma chamber surrounded by a 4.5-turn antenna. The plasma is ignited by a pulsed DC spark gap and then driven by a 2 MHz solid-state amplifier with a repetition rate of 25 Hz. The commissioning of the source started in the January of 2019. When un-cesiated, it produced more than 30 mA beam at an RF power of 32 kW and pulse width of 450 $\mu$s. Further improvements are still ongoing.

      Speaker: Dr Weidong Chen (Institute of High Energy Physics (IHEP), Chinese Academy of Science.)
    • 16:00 16:20
      Upgrading the LANSCE Accelerator Complex with a SNS RF-driven H- Ion Source 20m

      The LANSCE (Los Alamos Neutron Science CEnter) accelerator complex is currently driven by a filament-powered, biased converter-type H- ion source that operates at a high plasma duty factor of 10%. This is the world’s highest duty factor for pulsed high-current H- accelerators using only ~2.2 sccm of H2 (standard cubic centimeter per minute). The ion source needs to be replaced every 4 weeks with a ~4 day startup phase. The measured negative beam current of 16-18 mA falls below the desired 21 mA acceptance of the LANCSE accelerator especially since the beam contains several mA of electrons.
      On the other hand the SNS (Spallation Neutron Source) RF-driven, H- ion source injects ~50 mA of H- beam into the SNS accelerator at 60 Hz with a 6% duty factor and an availability of ~99.9%, but requiring ~30 sccm of H2. Up to 7 A·hrs of H- have been produced during the up to 14-week long service cycles, which is an unprecedented lifetime for small emittance, high-current pulsed H- ion sources. The SNS source also features unprecedented low Cs consumption and can be installed and started up in <10 h.
      LANSCE and SNS are considering the use of a SNS H- ion source on the LANSCE accelerator because it should a) decrease the source replacement time by a factor of ~8, b) increase source lifetime by a factor of 2-3, and c) increase the accelerator power by up to ~40%. However, this is a significant challenge as characteristics and normal operating regimes are drastically different. This talk will report on operating the SNS source with a 10% duty factor and adapting the small-diameter, small-emittance SNS beam to the 2-solenoid magnetic LANSCE LEBT (low- energy beam transport).

      Acknowledgment:
      This work is performed at Los Alamos National Laboratory under contract DE-AC52-06NA25396 and at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 and for the U.S. Department of Energy.

      Speaker: Martin Stockli (Oak Ridge National Laboratory)
    • 16:20 17:50
      Coffee Break: Poster Session - TueP C02, C03, C04, C07
    • 08:30 09:00
      Plasma Diagnostic Tools for ECR Ion Sources – What Can We Learn from These Experiments for the Next Generation Sources 30m

      The performance of Electron Cyclotron Resonance Ion Sources (ECRIS), producing high charge state ions from a great variety of elements, has improved dramatically over the past decades, thus enabling significant advances in accelerator-based nuclear physics. The order-of-magnitude performance leaps of ECR ion sources result from improvements to the magnetic plasma confinement, increases in the microwave heating frequency and techniques to stabilize the plasma at high densities. Parallel to the technical development of the ion sources themselves significant effort has been directed into development of their plasma diagnostic tools. We review recent results of ECRIS plasma diagnostics including e.g. wall and plasma bremsstrahlung, optical emission spectroscopy, measurement of the electron energy distribution as well as various time-resolved measurements on conventional and charge breeder ion sources yielding information on ion confinement and production times. Particular attention will be given to techniques used for studying plasma instabilities. The plasma diagnostics experiments and their results are compared to those obtained with fusion mirror machines, being direct ancestors of modern ECR ion sources. The data obtained mostly with the second-generation ECR ion sources operating at frequencies from 10 to 18 GHz are assessed to answer questions such as: “What can we learn from these experiments for the next generation sources?”, and “Which plasma diagnostics experiments should be carried out with the high-performance 3rd generation sources operating at frequencies higher than 20 GHz to pave the way for the next generation sources?”. Finally, we present a conceptual design of a permanent magnet ion source with quadrupole magnetic field topology and describe how this device could be used for validating certain trends emerging from the plasma diagnostics experiments with conventional minimum-B sources and how this information could open the door for source designs based on higher frequencies and stronger magnetic fields.

      Speaker: Olli Tarvainen (STFC Rutherford Appleton Laboratory)
    • 09:00 09:30
      ECRIS Plasma Spectroscopy with a High Resolution Spectrometer 30m

      Electron cyclotron resonance ion source (ECRIS) plasmas contain high-energy electrons and highly charged ions. This kind of plasmas are very sensitive to outside disturbance, which means that only non-invasive methods are reliable in their characterization. One of the spearheads of the JYFL ion source group has been to utilize the spontaneous de-excitation of electronic states of atoms, ions and molecules for diagnostics. This enables studying multiple plasma parameters non-invasively through optical emission spectroscopy (OES) of weak emission lines characteristic to ECRIS plasmas. A high-resolution spectrometer (10 pm FWHM at 632 nm) coupled with a lock-in data acquisition setup has been developed at JYFL specifically for this purpose.
      Densities of ions, neutral atoms and the temperature of the cold electron population play a major role in determining the different reaction rates such as ionization of neutrals and low charge state ions, excitation to radiative and metastable states, and charge exchange. Methods to study these plasma parameters with high resolution OES and results from measurements with the JYFL 14 GHz ECRIS will be presented. The temperature of the cold electron population can be studied using a line-ratio method. For example, it has been observed that the cold electron temperature drops from 40 eV to 20 eV when the extraction voltage of the ion source is switched off, accompanied by almost two orders of magnitude decrease in Ar$^{9+}$ optical emission intensity [1]. This suggests that diagnostics results of ECRIS plasmas obtained without the extraction voltage are not depicting the plasma conditions during normal ECRIS operation. The relative changes of both the plasma optical emission and the ion beam current have been measured in CW and amplitude modulation (AM) operation mode of microwave injection. It is concluded that in the normal CW operation mode the ion currents could be limited by diffusion transport and electrostatic confinement of the ions rather than beam formation in the extraction region and subsequent transport [2]. The study also revealed discrepancies between the parametric dependencies of high charge state ion densities in the core plasma and their extracted beam currents.
      The high resolution of the spectrometer also allows to study the ion temperature by measuring the Doppler broadening of the emission lines after subtracting the wavelength dependent instrumental broadening. The measured ion temperatures in the JYFL 14 GHz ECRIS are between 5–28 eV, depending on the plasma species and charge state [3]. These values are significantly higher than has been generally accepted for ECR plasmas. The effect of gas mixing on the measured ion temperature will be presented when oxygen is injected to pure argon plasma. It was found that 1+ ions reach temperatures on the order of 10 eV, which cannot be explained by ion heating via electron drag and therefore other possible heating mechanisms will be discussed.
      Finally, future plans to upgrade the spectroscopic setup to enable time-resolved measurements of the optical emission line broadening with millisecond resolution will be presented and the prospects of such experiments discussed.

      References
      [1] R. Kronholm et al., Review of Scientific Instruments 89, p. 043506, 10.1063/1.5023434, (2018)
      [2] R. Kronholm et al., Proceedings of the 17th International Conference on Ion Sources, p. 040014,
      10.1063/1.5053288, (2018)
      [3] R. Kronholm et al. (accepted manuscript), Plasma Sources Science and Technology, 10.1088/1361-6595/ab27a1, (2019)

      Speaker: Mr Risto Kronholm (Department of Physics, University of Jyväskylä)
    • 09:30 09:50
      Low energy highly charged ion beam production and the future opportunities for HCI physics at IMP 20m

      LEAF is a user facility, designed to produce and accelerate heavy ions, from H2 to U with M/Q between 2 and 7, to the energy of 0.5 MeV/u. The facility is mainly composed by a 45 GHz ECR ion source FECR, a 300 kV high voltage platform, a high intensity low energy beam transport line, a CW 81.25 MHz 4-vane radio frequency quadrupole (RFQ), and a medium energy beam transport line and several experimental terminals. This paper will report on the status of LEAF at IMP that will provide new opportunities for highly charged ion physics.

      Speaker: Yao Yang
    • 09:50 10:10
      Well-controlled emittance of the metallic ion beam extracted from the 28-GHz Superconducting ECR ion source adapting the superconducting acceleration cavity for new super heavy elements research 20m

      To increase the intensity of heavy-ion beams such as V and Cr for synthesizing new super heavy elements (SHE) with Z ≧ 119, we started to upgrade RIKEN Linear Accelerator (RILAC) as well as its electron-cyclotron resonance ion source (ECRIS) in 2017. The new ECRIS consists of a high temperature oven as a metal vaporizer and fully SC magnets, and is designed to produce the several hundred µA class metal-ion beams using 18-GHz and 28-GHz microwave heating. We successfully extracted very stable V$^{13+}$ beams of ~150 $\mu$A (more than 10 particle $\mu$A) with the 1-kW microwaves during 10-days commissioning period this June. RILAC is upgraded by adding superconducting (SC) rf cavities. Beam losses in the cold section, not only in the SC cavities but also in the beam pipes neighboring them, give serious contamination on the surface of the cavities. Then, it drastically decreases the acceleration voltage. Thus, the high-intensity beam with well-controlled emittance is required for this SHE project. To meet the requirement, we installed a slit triplet around a double focal point of the low energy beam transport (LEBT) to limit the transverse emittance of the ion beam with monitoring the emittance using several pepper-pot emittance meters. In addition, using the pepper-pot emittance meter, we can estimate the transverse 4-D phase-space distribution of the ion beam at the extraction of the ECRIS by the reversed beam tracking, and the 4-D distribution may give us information of the ionization process in the ECR plasma.
      In this contribution, we report the recent results of the commissioning of the LEBT, and discuss the possibility to reduce the beam emittance according to ionization process estimated from the 4-D distribution by adjustment the mirror field, positions of the oven, the microwaves and the supporting gas inlets.

      Speaker: Takashi Nagatomo (RIKEN Nishina Center)
    • 10:30 11:00
      Coffee Break
    • 11:00 11:30
      Status and perspectives for high intensity uranium beams from the RIKEN 28 GHz ECRIS 30m

      For RIKEN radioactive isotope beam factory (RIBF) project, the intense beam of highly charged uranium (U) ion beams was strongly required. Therefore, we tried to increase the beam intensity with 28 GHz RIKEN SC-ECRIS in last decade. For production of stable intense beam, it is obviously important to optimize both the ion source performance and U vapor production. For optimization of the ion source performance, we systematically studied the effect of the magnetic field distributions on the beam intensity of various heavy ions and applied it to produce the intense U beam. To produce U vapor, we chose two methods (sputtering and high temperature oven) and studied the effect of the various parameters (sputtering voltage, rod position, oven power etc) on the beam intensity. In this study, we also observed that the surface condition of the plasma chamber is important to produce intense beam with lower microwave power and lower consumption rate of the materials. Especially, the aluminum chamber plays important role to produce intense beam for long term operation.
       Using these results, we produced ~200 e$\mu$A of U$^{35+}$, 225 e$\mu$A of U$^{33+}$, 300 e$\mu$A of U$^{29+}$ at the microwave power of ~2.5 kW (28GHz+18 GHz). For long term operation (longer than one month), intense beam of U$^{35+}$ ions (120~140 e$\mu$A) was produced for the experiments of RIKEN RIBF project.
       To further increase the RI beam, the production of intense beam (more than 300 e$\mu$A of U$^{35+}$ ion beam) for long term is demanded. To meet the requirement, we have a plan to improve the oven system and ion source.
       In this contribution, I will present the results of the systematic studies and operational experience for production of intense U ion beam with RIKEN 28 GHz SC-ECRIS. The future plan to increase the beam intensity will be also reported.

      Speaker: Yoshihide HIGURASHI
    • 11:30 12:00
      New microwave coupling scheme for high intensity highly charged ion beam production by high power 24-28 GHz SECRAL ion source 30m

      The efficiency of the microwave-plasma coupling is a key issue to enhance the performance of electron cyclotron resonance ion sources (ECRISs) in terms of higher ion beam intensity yield. The coupling properties are affected by the microwave coupling scheme, especially for the high frequency and high power ECR ion sources. Based on the study of 24 GHz SECRAL ion source performances working at different launching systems, a new microwave coupling scheme is proposed in this paper, which can not only realize efficient power matching and feeding, but also effectively adjust the rf power distribution on the ECR surface. Here we describe these experiments and the results improve the understanding the microwave-plasma coupling properties on ECR ion source. Meanwhile, it will also provide a prototype for the development of the next generation ECRIS.

      Speaker: Dr Junwei Guo (Institute of Modern Physics)
    • 12:00 12:20
      Development of a Highly Efficient NEG Pumping System for EBIS 20m

      Ultra-high vacuum inside the ion trap volume is crucial for stable and reliable operation of an Electron Beam Ion Source (EBIS). We have developed and tested a compact linear pumping system based on ZAO NEG module with high pumping speed and enhanced sorption capacity for all active gases. Due to its minimal transverse dimensions, the system can be mounted adjacent to the ion trap inside superconducting solenoid bore and will provide pumping speed of the order of 1000 l/s for all active gases in that area. An externally supplied current (100 A DC) is used to heat ZAO NEG up to 650 °C for more than 1 hour, which is required for pump activation and/or reactivation cycles. The pumping system is being developed for use in the Extended EBIS Upgrade which is presently in progress at BNL. Design of the system and results of multiple tests will be presented and discussed in this presentation.

      Speaker: Sergey Kondrashev (BNL)
    • 12:20 13:50
      Lunch Break
    • 14:00 14:30
      First volume operation of the SPIDER source and beam 30m

      To reach fusion conditions and to control the plasma configuration in ITER, the next step in thermonuclear fusion research, two heating and current-drive neutral beam injectors (NBIs), each supplying 17MW, by accelerating negative hydrogen or deuterium ions to 1MeV. The requirements of ITER NBIs (40A negative H or D ions for 1 hour) have never been simultaneously attained. So in the dedicated Neutral Beam Test Facility (NBTF) at Consorzio RFX (Italy) the performances of the ITER NBI (divergence <7mrad, aiming <2mrad) will be studied and optimised. The NBTF includes two experiments: MITICA, full-scale ITER NBI prototype, and SPIDER, full-scale prototype of the ITER NBI source with 100keV particle energy. SPIDER aim is to investigate source uniformity (over a 1m×2m area), negative ion current density and beam optics.
      The present contribution will briefly outline the activities and the experiments carried out in the SPIDER beam source during its first year of operation with volume generation of negative ions. In order to extend the source pressure range and to provide a thorough investigation of the properties of the early SPIDER beams, a mask was installed in the accelerator, leaving only isolated beamlets (for a total number of ~100 beamlets out of 1280). The detailed investigation of the plasma properties, to assess the efficiency of RF coupling to the plasma in different configurations of the RF circuits, are presented. During the first extraction of negative particles from the source, the features of the co-extracted electrons were studied and correlated with the plasma parameters. Particularly, the magnetic filter field effectiveness in reducing the co-extracted electron current was verified; correspondingly, the decrease of the plasma emissivity was studied as well as the influence on the negative ion current. Finally the first characterisation of the SPIDER beam, in terms of beamlet divergence and deflection, is proposed and compared with numerical models while varying the source parameters. The negative ion beam is found to exhibit values of current density and optics similar to those expected in volume operation.

      Speaker: Gianluigi Serianni (Consorzio RFX)
    • 14:30 14:50
      Extension of High Power Deuterium Operation of Negative Ion Based Neutral Beam Injector in LHD 20m

      Deuterium operation of negative ion based neutral beam injector (N-NBI) was initiated in 2017 in the Large Helical Device (LHD). Negative ion sources and their accelerator were optimized for hydrogen operation. The specification of the H$^–$ current and the beam energy are 80 A and 180 keV, respectively. Total injection power was 16 MW for hydrogen operation by three beam lines. In the first deuterium beam operation, the D$^–$ current of 46.2A was generated with the averaged current density of 190 A/m$^2$ for the electron ion current ratio of $I_e/I_{D^-}$ = 0.39 by only changing operation gas using the same accelerator. In the second deuterium beam operation in 2018, the electron and ion current ratio decreases to $I_e/I_{D^-}$ = 0.31 using the short extraction gap distance of 7 mm between the plasma grid and the extraction grid. Thermal load on the extraction grid for deuterium operation is as low as that for hydrogen operation. The volume of negative ion rich region between the plasma grid and EDM(electron deflection magnetic) field lobe is considered to be increasing in the vicinity of PG surface. The reduction of the electron current made it possible to operate a high power arc discharge and beam extraction. Then the deuterium negative ion current increases to 55.4 A and the averaged current density of 233 A/m$^2$. The injection beam power increases from 2.3 MW to 2.9 MW in one beam line, and the total beam injection power increases from 5.3 MW to 7 MW by three beam lines in the second deuterium campaign.

      Speaker: Dr Katsunori Ikeda (National Institute for Fusion Science)
    • 14:50 15:10
      Formation of Large Negative Deuterium Ion Beams at ELISE 20m

      Negative hydrogen or deuterium ion sources for neutral beam injection in fusion devices are based on the surface production process at caesiated low work function surfaces. The development of the ion source for ITER NBI follows a R&D roadmap defined by the European ITER domestic agency F4E and includes as intermediate step the test facility ELISE. The ion source of ELISE has the same width but only half the height of the ITER NBI source ($0.9 × 1\,\mathrm{m}^2$). Aim of ELISE is to demonstrate the ITER requirements in terms of extracted negative hydrogen ion densities ($329\,\mathrm{A}/\mathrm{m}^2$ for hydrogen, $286\,\mathrm{A}/\mathrm{m}^2$ for deuterium) for an pulse length of up to one hour in deuterium ($1000\,\mathrm{s}$ in hydrogen), using pulsed extraction and demonstrating an electron-ion ratio of less than one and deviations from an uniform beam of less than $10\,\%$. The experience gained during operation of ELISE is an important input for the commissioning and operation of the Neutral Beam Test Facility PRIMA in Padova and the ITER NBI system itself.

      ELISE went into operation in 2013. Since then remarkable progress towards fulfilling the ITER requirements have been made. Recently, series of reproducible long pulses in hydrogen fulfilling the ITER requirement for the accelerated negative ion current have been demonstrated. Determined by IR calorimetry is an almost perfect global beam uniformity, which is degrading slightly (from $100\,\%$ to $90\,\%$) over the length of the pulse. These pulses represent a milestone towards operation of the ITER NBI system during the initial operational phase in hydrogen (up to 2035).

      The ongoing experiments at ELISE are mainly focussed on achieving the ITER requirements also in deuterium. The main challenge is to reduce a strong temporal increase of the co-extracted electrons. In parallel to this increase of the electrons, the extracted ions decrease slightly. The physical reasons behind these effects are not fully known up to now. They are much more pronounced in deuterium than in hydrogen and they can drastically restrict the achievable performance and/or the pulse length.

      The contribution focusses on long deuterium pulses (up to one hour) at ELISE and on the stabilization of the co-extracted electrons. First step are dedicated experiments giving insight into the physics behind the strong isotope effect regarding the co-extracted electrons between hydrogen and deuterium. For deuterium plasmas, these experiments demonstrated a strongly increased release of caesium from reservoirs at inner source surfaces and thus stronger depletion of Cs in long pulses. Several measures for affecting the caesium dynamics and thus reducing and stabilizing the co-extracted electrons, namely modifications of the electrostatic potentials and the magnetic field topology in the ion source, are presented. Finally, the results obtained using these measures are presented and discussed.

      Speaker: D. Wünderlich (Max-Planck-Institut für Plasmaphysik)
    • 15:10 15:30
      Cavity Ring-Down Spectroscopy system for the determination of negative hydrogen ion density at the ELISE test facility 20m

      The Neutral Beam Injection (NBI) system for ITER will rely on large and powerful RF sources of negative hydrogen (deuterium) ions, which are mostly produced by surface conversion of neutral hydrogen atoms on a converter surface (plasma grid). The ITER-NBI systems need to provide an accelerated ion current of 40 A in D$^{-}$ for up to one hour, with a co-extracted electron current lower than the extracted negative ion current. The efficiency of negative ion surface production is enhanced by decreasing the work function of the plasma grid and this is achieved by evaporating Cs inside the negative ion source.
      The large RF source at the ELISE test facility (half of the ITER-NBI source size) at IPP Garching has recently been equipped with a Cavity Ring-Down Spectroscopy (CRDS) system, in collaboration with the National Institute of Fusion Science (NIFS) in Toki, Japan. The aim is to measure the negative hydrogen ion density in front of the plasma grid. The system is based on the evaluation of the decay time of the intensity of a laser pulse (Nd:YAG at 1064 nm) inside a cavity formed by two high reflective mirror (R > 99.995 %). The comparison between the decay time during the vacuum phase (no plasma) and in plasma, i.e. with the additional absorption of radiation due to photo-detachment of negative hydrogen/deuterium ions, allows for the determination of the line integrated density of negative ions. The high reflectivity of the mirrors is needed to achieve a high decay time (tens of microseconds) and therefore the required sensitivity for the detection of negative ions. The stability of the mirror reflectivity is also of importance for the reliability of the system: both temporary and permanent degradation of the mirror reflectivity can indeed take place in an ion source environment, as observed in the prototype source at the BATMAN test facility.
      As the presence of the magnetic filter field in the horizontal direction causes a vertical plasma drift, two horizontal lines of sight at 2 cm distance from the plasma grid are dedicated to CRDS, in order to gain information on the vertical distribution of the negative ion density. This work will present the results of the first measurements, focusing on the investigations performed to ensure the reliability of the mirror reflectivity and on the dependence of negative ion density on the discharge parameters such as power, pressure and magnetic filter field intensity. Experiments performed both in volume production operation (no Cs evaporation) and in surface production operation (caesiated source) have shown that the system is reliable for long pulse duration (thousand seconds) and for high RF power. Typical value of the negative ion density measured at ELISE during surface production operation were in the range between 5·10$^{16}$ and 10$^{17}$ m$^{-3}$, and only a limited vertical asymmetry (less than 50% difference between the two lines of sight) was observed, in dependence with the magnetic filter field configuration and the bias voltage.

      Speaker: Dr Alessandro Mimo (Max-Planck-Institut für Plasmaphysik)
    • 15:30 15:50
      Improvements of the NIO1 Installation for Negative Ion Sources 20m

      In view of the long term operation of neutral beam injectors (NBI) used for stellarator and tokamak heating and current drive, the negative ion source must be carefully optimized, especially because not only plasma but also surface wall conditions are involved in H- or D- production. The NIO1 (negative ion optimization phase 1) installation was developed and is operated since 2014 (in close collaboration between Consorzio RFX and INFN), as a convenient benchmark to study innovative solutions and to address physical questions. The comparatively smaller size of NIO1 (a relatively compact and modular 9 beamlet H- source) is of evident advantage for detailed modeling. The apparent plasma impedance is well in agreement with negligible rf reflection at plasma on, and reflections with plasma off (about 25 %) are well within limits tolerable by rf amplifier; transition between E and H modes of rf coupling can be controlled by increasing rf power or by decreasing gas pressure. The filter field intensity, Bx, has been extended to span the [-12, 5] mT range, and as a trend, source performances improve with |Bx|.
      Status and results of a first NIO1 cesium oven are reported. Installation of the Cavity Ring Down Spectrometer (CRDS) and recent years progress of beam diagnostics and of the quality of the volume-produced H- beam are briefly discussed, together with the status of the NIO1 full power "end calorimeter/beam imaging attenuator", to be placed at the end flange with auxiliary flanges for infrared observation. Conceptual tests of energy recovery system, perhaps using this full power calorimeter are also summarized.

      Speaker: Marco Cavenago (INFN-LNL)
    • 15:50 16:10
      R&D progress of RF ion source for neutral beam injector at ASIPP 20m

      Neutral beam injection (NBI) is one of the most effective tools of four auxiliary plasma heating methods for fusion plasma heating and current driven. Now, a next generation fusion device, China Fusion Engineering Test Reactor (CFETR) is under design, and a giant negative neutral beam injector (NNBI) will be developed is foreseen. In order to demonstrate the key technology and performance of negative ion source, a negative RF ion source test facility has been developed since 2017 in the Institute of Plasma Physics, Chinese Academy of Science (ASIPP).
      A prototype single driver ion source with dimension of 200mm was developed and tested on the test facility to pre research the key technology of RF plasma generator. The driver equipped with a water-cooled Faraday shield to protect the alumina cylinder from the plasma and the plasma expands into the rectangular expansion chamber. The RF power of 50 kW with frequency of 1MHz is transferred to the RF driver by a matching unit. The characteristics of plasma discharge were studied with classical diagnostic tools, such as Langmuir probe, optical emission spectroscopy (OES) and water-flow calorimetry (WFC). Based on the plasma performance tests, high power of 50 kW plasma discharge with long pulse of 1000s was achieved. In this paper, the detail design of ion source, characteristics of plasma and future research plan will be presented.

      Speaker: Dr yahong xie
    • 16:10 17:50
      Coffee Break: Poster Session - WedP C05, C08, C09
    • 08:30 09:00
      Optical Characteristics of Negative Ion Beam with Multi-Beam-Axes Produced by LHD-type Negative Ion Source 30m

      Optimization of negative-ion beam optics is a key issue for high-power negative-ion-based neutral beam injection (NBI) development for application to nuclear fusion research. The application of negative-ion-based NBI to the experiments of magnetically confined plasmas have been successfully demonstrated in Large Helical Device (LHD) and JT60-U, in which filament-arc negative ion sources have been developed. We developed an accelerator with slot-grounded grid for the NBI on LHD and it was simultaneously achieved both to increase beam power and to keep the beam divergence in the low level, typically, around 5 mrad [1]. On the other hand, the beam divergence angle of ITER-like RF negative ion source has not achieved the ITER requirement. Therefore, further understanding of beam optical property of negative ion beam is required to further improvement of beam divergence angle.
      In this study, the experimental investigation of the phase space structure (emittance diagram) of negative ion beam produced with a Research & development Negative Ion Source at National Institute for Fusion Science (NIFS-RNIS) which is scaled a half volume to LHD sources was carried out, and three beam components were identified within a single beamlet in horizontal direction, in which the negative ion beam is bended by electron deflection magnetic field. The spatial profile of each beam component is available to be fit with Gaussian profile; i.e. the beamlet is separated into three Gaussian beams. The experimental investigation how the three Gaussian beams behave reveals that the focal condition for 1/e width of each Gaussian beam coincides the condition that three beam axes converges, which is considered as a reason why the divergence angle is so small in our filament-arc source. In the conference, the beam phase space structure in the vertical direction and the origin of three beam axes will also be discussed.

      Speaker: Kenichi Nagaoka (National Institute for Fusion Science, National Institutes of Natural Sciences)
    • 09:00 09:20
      Design and development of an Allison type emittance scanner for the SPIDER ion source 20m

      Low divergence negative ion beams are crucial for the development of ITER-like fusion reactors. SPIDER is the prototype beam source of the ITER Heating Neutral Beam Injector, and it recently started beam acceleration, up to a voltage of 30 kV. The main diagnostics used to measure beamlet divergence are a movable diagnostic calorimeter (STRIKE), which gives the thermal footprint of the beamlets, beam emission spectroscopy and visible imaging. These systems do not allow a direct measurement of single beamlet phase-space distribution, which is useful for the comparison with numerical simulations and to estimate accelerator performances.
      To this purpose, a movable Allison type emittance scanner for the SPIDER negative ion beam was developed and proposed for the installation on the STRIKE supporting structure. This paper describes the numerical analyses performed to dimension the mechanical and electrical components, such as the Faraday cup and the slits. An analytical approach based on the integration of an arbitrary phase-space distribution was adopted in order to simulate the device performances. The constraints due to the operation in a high heat load environment are discussed.

      Speaker: Mr Carlo Poggi (Consorzio RFX)
    • 09:20 09:40
      Generation of boron ion beam by different methods 20m

      The report provides an overview of recent work on the generation of boron ions in the laboratory of Plasma Sources of the Institute of High-Current Electronics, Tomsk, Russia. To obtain boron ions, pulsed discharge systems of a vacuum arc discharge and a high-current magnetron discharge in self-sputtering mode were used. In both discharge systems, cathodes from pure boron and lanthanum hexaboride were used to generate boron-containing plasma. In the experiments, the main attention was paid to the study of the mass-charge composition of the ion beam and the search for conditions provided the achievement of the maximum fraction of boron ions in the ion beam.

      Speaker: Prof. Efim Oks (HCEI)
    • 09:40 10:00
      Brightness Award
    • 10:00 10:30
      OPTICALLY-PUMPED POLARIZED H- AND 3HE++ ION SOURCES DEVELOPMENT AT RHIC 30m

      The RHIC Optically-pumped Polarized H- Ion Source (OPPIS) upgrade with the atomic beam hydrogen injector and the He-ionizer cell was commissioned for operation in the Run-2013. The use of the high brightness primary proton source resulted in higher polarized beam intensity and polarization delivered for injection to Linac-Booster-AGS-RHIC accelerator complex. The proposed polarized 3He++ acceleration in RHIC and future electron- ion collider (eRHIC) will require about 2∙1011 ions in the source pulse. A new technique had been proposed for production of high intensity polarized 3He++ ion beam. It is based on ionization and accumulation of the 3He gas (polarized by optical-pumping and metastability-exchange technique in the high magnetic field of a 5.0 T) in the Electron Beam Ion Source (EBIS). We present a status of the 3He++ ion source development.

      Speaker: Anatoli Zelenski (BNL)
    • 10:30 11:00
      Coffee Break
    • 11:00 11:20
      Achievement of High Power and Long Pulse Negative Ion Beam Acceleration for JT-60SA NBI 20m

      High power density of hydrogen negative ion beams with over 70 MW/m2 at the energy of 500 keV has been demonstrated stably over 100 s by using a multi-aperture and three-stage accelerator. Such continuous negative ion beam accelerations over 100 s with high power density has never been achieved before in the world. This result fulfills the requirement of the negative ion source for the neutral beam injector (NBI) of JT-60SA (500 keV, 130A/m2 for 100 s) and also contributes to the 1 MeV negative ion accelerator for the ITER NBI.
      In this negative ion source, Cesium (Cs) is seeded to enhance the negative ion production near the plasma grid. However, anomalous discharge, so-called arcing, which causes damage on filament, was observed when the Cs is seeded. This has limited the arc power and pulse length. In addition, negative ion current was gradually decreasing after 50 s because Cs evaporated from the chamber wall excessively deposits on the plasma grid when the chamber wall temperature is increased over 60 degree Celsius [1, 2]. For high energy beam acceleration, it has been concerned that the voltage holding capability is degraded when Cs leaks to the accelerator.
      In this test, a small KAMABOKO ion source is attached on the top of the three-stage accelerator, whose aperture arrangement and the gap lengths are the same ones as the negative ion source of JT-60SA. To inject the necessary arc power with less filament damage, the input energy to the filament was successfully reduced from 10.6 J to 0.4 J by installing fast cutoff system of the arc power supply at 500 kV stage. To maintain the stable negative ion production, excess Cs from the chamber wall to the plasma grid could be suppressed by maintaining the wall temperature around 50 degree Celsius. As the result, 500 keV and 130 A/m2 beams have been achieved. The power loads on each acceleration grid were lower than the allowable value of 5 % of the total beam power. Then, the pulse length was gradually extended.
      Even though the power loads on the grid was sufficiently low for the long pulse operation, the pulse length was limited up to 60 s initially due to breakdowns. This result indicates that cause of the breakdown is not only the thermal loads on the acceleration grids but also particle incident to these grids by beams. To extend the pulse length, the long pulse beam acceleration has been tried at slightly low energy of 400 keV. Consequently, the pulse length has been gradually extended over 60 s, and finally reached to 175 s. After that, pulse length of 500 keV beam was gradually extended, and reached over 100 s. Finally, acceleration of 500 keV, 154 A/m2 beams for 118 s has been achieved. No degradation of voltage holding capability for extraction and acceleration was observed even after the total amount of Cs injection corresponded to the same level of JT-60U by extrapolation of the chamber size. These operational technique for long pulse operation can be directly applied to JT-60SA NBI, and contribute to the ITER accelerator.

      Speaker: Dr Junichi Hiratsuka (QST)
    • 11:20 11:40
      Installation and Commissioning of the Ion Source Systems for the New SNS 2.5 MeV Injector 20m

      The U.S. Spallation Neutron Source (SNS) is a state-of-the-art neutron scattering facility delivering the world’s most intense pulsed neutron beams to a wide array of instruments which are used to conduct investigations in many fields of engineering, physics, chemistry, material science and biology. Neutrons are produced by spallation of liquid Hg by bombardment of short (~1s), intense (~40A) pulses of protons delivered at 60 Hz by a storage ring which is fed by a high-intensity, 1 GeV H- LINAC. This facility has operated nearly continuously since 2006 but has recently undergone a 4-month maintenance period which featured a complete replacement of the 2.5 MeV injector feeding the LINAC. The new injector was developed at ORNL in an off-line beam test facility and consists of an ion source, Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ). This report first describes the installed configuration of the new injector detailing the ion source system. The first beam current, RFQ transmission, emittance and energy measurements from the injector installed on the SNS are reported which not only show a significant performance improvement for our existing facility but will now make accessible the higher beam current requirements for future SNS upgrade projects: the Proton Power Upgrade (PPU) and Second Target Station (STS).

      Speaker: Dr Robert Welton (ORNL)
    • 11:40 12:00
      Prospect of Cs-free hydrogen negative ion sources Using C12A7 Plasma Electrodes 20m

      A new inorganic material, C12A7 electride [1,2] has been experimentally studied as a candidate material for Cs-free hydrogen negative ion (H-) sources. A high production rate of H- was observed from a C12A7 electride surface immersed in hydrogen/deuterium low-pressure plasmas [3]. In our previous work using a compact ECR ion source [4], it was found that the H- current extracted from the source with an electride Plasma Electrode (PE) is higher that with a clean molybdenum, by a factor of 80-100, as expected from the experimental results at Marseille [3]. However, the absolute values of beam intensity were too low for an actual use and the dependence of H- current on the microwave power, was not observed clearly.
      In the present study, key issues to realize a compact H- source for the actual use in accelerator injectors are investigated. Firstly, the ECR ion source was modified so that a dense plasma from the ECR region could be injected directly towards the PE. Preliminary results showed a clear dependence on the microwave power and the H- current increased by more than a factor 10.
      In H- production on the cesiated metal surface, the work function (WF) of the surface plays the essential role because the H- electron might transfer back to empty states of the conduction band during it is moving away from the surface. In case of C12A7 electride, the connected cages form a new conduction band called “cage conduction band” (CCB). The WF from CCB is as low as 2.4 eV, but there is a wide gap to valence band maximum (~5.5 eV) from CCB. Moreover, it is reported that some of the encaged electron are replaced by the H- ions when the electride is exposed to hydrogen circumstance. Considering these aspects, the effect of the extraction hole shape, and the correlation to the surface work function of the electride PE will be studied, and prospects to a H- source for the actual use will be discussed.

      References
      [1] Y. Toda, H. Yanagi, E. Ikenaga, Jung Jin Kim, M. Kobata, S.Ueda, T. Kamiya, M. Hirano, K. Kobayashi, and H. Hosono, Advanced Materials 19, 3564 (2007).
      [2] H. Hosono, Japanese Journal of Applied Physics 52 (2013) 090001.
      [3] M. Sasao et al., Applied Physics Express 11, 066201 (2018).
      [4] M. Kobayashi et al, AIP Conference Proceedings 2052, 020003 (2018).

      Speaker: Mamiko Sasao (Office of R&D Promotion, Doshisha University)
    • 12:00 12:20
      A Pre-injector Upgrade for the ISIS Pulsed Spallation Neutron Facility, Including a Medium Energy Beam Transport Line and an RF-Driven, Non-Caesiated, External-Antenna H– Ion Source 20m

      The ISIS pulsed spallation facility at the Rutherford Appleton Laboratory has been delivering powerful beams of neutrons and muons for materials characterization studies since 1984. The negative hydrogen (H–) linac was upgraded in 2004 with the addition of a ‘pre-injector’ based around a 665 keV radio-frequency quadrupole (RFQ). A Penning-type caesium-enhanced surface-plasma ion source supplies the pre-injector with around 55 mA of H– beam current. Limitations in beam transport efficiency from both the ion source and between the RFQ and drift-tube linac (DTL) mean over 50% of beam current is lost between the ion source and synchrotron. Moreover, the Penning source lifetime is limited by cathode material sputtering inside the plasma discharge chamber. As such, facility operations must be stopped every two to three weeks to replace the ion source.
      To address these issues, a project is underway to upgrade the pre-injector with the addition of a medium-energy beam transport (MEBT) line. A fast electrostatic sweep chopper is included in the MEBT and will notch the linac bunch train at the synchrotron frequency. The MEBT and chopper will increase beam transport efficiency significantly, reducing the output H– current requirements from the ion source. As such, a long-lifetime, non-caesiated, RF-driven, external-antenna H– ion source based on the successful CERN Linac4 and SNS designs is being constructed which will improve facility up-time and reliability.
      This paper will highlight latest developments on the MEBT before focusing on the RF ion source. The RF ion source must deliver 35 mA of H– beam current in pulses 400 µs long at 50 Hz repetition rate, with a transverse normalised 4.RMS emittance less than 1.2 π mm mrad. The beam current and emittance are within reach of a non-caesiated H– source, whereas operating at relatively high duty cycles presents challenges in terms of thermal management. In particular, serious consideration must be paid to safe removal of a high current co-extracted electron beam. Other novel developments to be discussed include a low power electron source as a plasma igniter, a solid-state 2 MHz 100 kW RF amplifier, a 3D-printed cooling jacket, an adjustable permanent-magnet filter field and low energy beam transport (LEBT) beam tracking studies. The detailed ion source and LEBT designs are complete and first machined components are due at the end of 2019. Vacuum, high voltage and interlocks commissioning will start in Spring 2020, with first beam expected towards the end of 2020.

      Speaker: Dr Scott Lawrie (UKRI)
    • 12:20 13:20
      Lunch Break
    • 13:30 18:30
      OUTING
    • 19:00 22:00
      Conference Dinner
    • 08:30 09:00
      The role of ion sources in synthesis of the super-heavy elements 30m

      Since the early 70s, attempts to synthesize Super Heavy Elements (SHE) have been made in many laboratories around the world. One of the main requirements of these experiments is a sufficiently large dose of target irradiation, which should be increased with a decrease in the reaction cross section. In this regard, the capacities of ion sources play an important role for the successful synthesis of SHE.
      At the FLNR JINR the discovery and investigation of the new region of super heavy nuclei were based on fusion reactions of 48Ca with 238U–249Cf target nuclei. In these experiments, a technique for the production of metallic 48Ca was developed. The operation mode of the ECR ion source was set to optimize the intensity of 48Ca ions and attain maximum ionization efficiency.
      Because of the heaviest target for experiments on synthesis of SHE in heavy ion reactions is 249Cf, so further progress in the synthesis of elements with Z > 118 requires the production of intense beams of accelerated neutron enriched isotopes, such as 50Ti, 58Fe, 64Ni, etc.

      Speaker: Andrey Efremov (JINR)
    • 09:00 09:30
      Ion Thrusters and Electrical Propulsion Developments 30m

      The transition from old space to new space along with increasing commercialization has a major impact on space flight in general and on electric propulsion by ion sources in particular. The requirements of space industry for electric propulsion systems, e.g., ion thrusters as well as their peripheral devices, change rapidly. We will discuss some of the major developments and corresponding research tasks arising. Commercialization implies mass production at a low price. This has at least two major impacts: (i) shorter product development cycles, i.e., new products should enter the market more rapidly, and (ii) resource efficiency become important. For example, shorter development times require that the qualification procedures for thruster systems need to be rethought. How much ground testing is necessary? How can modelling help to speed up qualification and to predict lifetimes and performance in space? Resource efficiency implies that scare materials should be avoided, e.g. xenon is scarce and not enough xenon is available as propellant for electric propulsion as a mass product, at least, not at a compatible price. Alternatives need to be sought. Are there suitable molecular propellants and what is the right strategy finding them? Is reactive iodine a cheap alternative to xenon as propellant? Prices of electric propulsion systems may also be considerably lowered by employing commercially available electronic components as part of the electric propulsion system. These components may have to be used beyond their specifications under extreme conditions, e.g., in the radiation environment of the Van-Allen belt. How to find suitable radiation-hard electronics? Formation flights of cheap and small satellites are an essential part of a data network. What does miniaturization imply? To which extent are current electric propulsion systems miniaturizable? How can electromagnetic compatibility with the environment on the satellite be tested and guaranteed?

      Speaker: Peter J. Klar (University of Giessen)
    • 09:30 09:50
      Capabilities of radio-frequency ion-sources in surface modification of materials 20m

      The capabilities of ion-beam techniques for thin-film processing, i.e., for materials deposition by ion-beam sputtering and surface treatment, are reviewed. The basic interaction mechanisms between ions and solids are summarized and related to materials processing by ion sources. The applicability of ion-beam techniques in the controlled modification of surfaces is discussed and critically compared with wet-chemical etching procedures. Masking areas of a sample surface and, thus, protecting the surface below the mask from ion bombardment, is the basis of structuring surfaces by ion-beam etching. On the microscale and nanoscale, masks as structured coatings are typically generated by lithographic methods such as photolithography and electron-beam lithography.
      Examples will be given, how ion-beam technology can unfold its potential in modifying surface topography by means of broad-beam bombardment with positively charged ions. Herein, we will focus on the transfer of the extraction grid pattern into primary and secondary beam.

      Speaker: Dr Martin Becker (Institute of Experimental Physics, Heinrich-Buff-Ring 16, Justus Liebig University Giessen, D-35392 Giessen, Germany)
    • 09:50 10:10
      Present status of ion sources at QST-NIRS and carbon-ion radiotherapy facilities 20m

      NIRS-QST carries out research and development (R&D) life sciences:, including: the effects of radiation on the human body; protection from radiation, including diagnosis and treatment of radiation injuries; and medical applications of radiation. To fulfill its R&D aims, NIRS-QST maintains a number of accelerators, including: two tandem accelerators, one large heavy-ion accelerator complex consisting of two synchrotrons and four linacs for heavy-ion radiotherapy, and three cyclotrons. Various types of ion sources supply the ion species required by the accelerators, and are used across various ion beam applications. A duoplasmatron ion source is installed in the 1.7 MV tandem accelerator for experiments requiring a particle-induced x-ray emission (PIXE) and micro beam irradiation systems. A muti-cusp ion source is installed in the 2.0 MV tandem accelerator for studies requiring neutron exposure. An ECR ion source is installed in the K=110 cyclotron (NIRS-930) not only for nuclear medicine but also for biology, physics, and material science experiments. The Heavy Ion Medical Accelerator in Chiba (HIMAC) has been used to conduct heavy-ion radiotherapy and basic experiments since 1994. Three electron cyclotron resonance (ECR) ion sources and a Penning ionization gauge (PIG) ion source are installed in the injector system of HIMAC. PIG ion sources are also installed in the two commercial cyclotrons for nuclear medicine. In this paper, the status of ion sources and some results of development are described.
      A compact ECR ion source, named Kei2, has been developed for carbon-ion radiotherapy at QST-NIRS. After the successful performance test, Kei-series, a commercial version of Kei2, are used at four Japanese facilities at present and another will be installed in the 7th facility in Japan. Additionally, two sources are under construction at Seoul and Taipei. These facilities are optimized for the production of only carbon ions in order to reduce the initial construction cost and efforts of operation. Since one Kei-series source is installed in each facility, the reliability of ion source is very important. All Kei-series have sustained daily treatment. The status of Kei seriesis are also reported.

      Speakers: Masayuki Muramatsu (National Institute of Radiological Sciences), Dr Atsushi Kitagawa (National Institute of Radiological Sciences)
    • 10:30 11:00
      Coffee Break
    • 11:00 11:40
      Young Scientist Award
    • 11:40 12:10
    • 12:10 12:30
      Conference Closing Ceremony
    • 12:30 13:50
      Lunch Break
    • 14:00 16:20
      Lab Tour
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