Keyword: plasma
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MOCOAK01 SECRAL Status and First Beam Test at 24GHz ion, ECR, heavy-ion, ion-source 1
 
  • H.W. Zhao, Y. Cao, Y.C. Feng, X.H. Guo, J.Y. Li, W. Lu, L.T. Sun, D. Xie, X.Z. Zhang, H. Zhao
    IMP, Lanzhou, People's Republic of China
  
  SECRAL has been in routine operation at 18GHz for HIRFL (Heavy Ion Research Facility in Lanzhou) accelerator complex since May 2007. It has delivered many highly charged heavy ion beams for the HIRFL accelerator and the total beam time so far has exceeded 3000 hours. To further enhance the SECRAL performance, a 24GHz/7kW gyrotron microwave amplifier has been installed and tested. Very exciting results were produced with quite a few new record highly-charged ion beam intensities. Bremstrahlung measurements at 24GHz have shown that X-ray is much stronger at higher RF frequency, higher RF power and higher minimum B field. Beam emittance study has been conducted in order to improve the beam brightness. An additional cryostat with five GM cryocoolers was installed atop the SECRAL to liquefy the boil-off helium gas to minimize the liquid helium consumption. The latest results and reliable long-term operation for the accelerator have once again demonstrated that SECRAL is one of the best performance ECR ion source for the production of highly-charged heavy ion beams. Detailed and future developments of SECRAL will be presented.  
slides icon Slides MOCOAK01 [4.739 MB]  
 
MOCOAK02 Intense Beam Production with SuSI ion, ECR, ion-source, ECRIS 4
 
  • L.T. Sun, J. Brandon, D.G. Cole, M. Doleans, G. Machicoane, D. Morris, T. Ropponen, L. Tobos
    NSCL, East Lansing, Michigan, USA
  • E. Pozdeyev
    FRIB, East Lansing, Michigan, USA
  
  SuSI ion source, a 3rd generation fully superconducting ECR ion source is now used for injection into the Coupled Cyclotron Facility since September 2009. Initial performances during the commissioning of SuSI were mainly limited by the microwave power available from a single 18 GHz microwave amplifier, especially for the production of heavier ion beams. The Injection of SuSI was modified to add a second 18 GHz amplifier, to reach a maximum of 3.0 kW of RF power inside the plasma chamber. Production of heavy ion beams, such as Kr14+, Bi30+ and U33+ is reported, to demonstrate the performance of SuSI. Additional studies were made with various ion source parameters to optimize the beam intensity within a normalized emittance of 0.9pi.mm.mrad as needed for the FRIB project and will be reported in this paper.  
slides icon Slides MOCOAK02 [1.672 MB]  
 
MOCOAK04 Status of the VENUS ECR Ion Source ion, ion-source, ECR, cyclotron 11
 
  • D. Leitner, P. Ferracin, A. Hodgkinson, M. Leitner, T.J. Loew, C.M. Lyneis, G.L. Sabbi
    LBNL, Berkeley, California, USA
  • G. Machicoane, E. Pozdeyev
    NSCL, East Lansing, Michigan, USA
  
  The fully superconducting 28-GHz VENUS ECR ion source serves as prototype injector for the Facility for Rare Isotope Beams (FRIB) project at Michigan State University (MSU) as well as injector ion source for the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). As such the source has produced many record beams of high charge state as well as high-intensity, medium charge state ions. As the FRIB project has now entered the preliminary design phase, Lawrence Berkeley National Laboratory is involved in the design of two new VENUS-like ECR injector ion sources for the FRIB facility. This paper will review the requirements for the FRIB injector, and present VENUS cryostat design changes which will allow installation on a 100 kV platform. In addition, a possible future upgrade path for the FRIB injector using an advanced Nb3Sn magnet structure is described. In 2008, at LBNL the VENUS ECR ion source experienced a major setback when one of the sextupole leads evaporated during a quench caused by a low liquid helium level in the cryostat. The repair process and the long reconstruction effort as well as the status of the reinstallation will be described.  
slides icon Slides MOCOAK04 [4.180 MB]  
 
MOCOBK03 Status of Ion Sources at HIMAC ion, ion-source, ECR, radiation 20
 
  • A. Kitagawa, M. Muramatsu, Y. Sakamoto
    NIRS, Chiba-shi, Japan
  • S. Biri
    ATOMKI, Debrecen, Hungary
  • A.G. Drentje
    KVI, Groningen, The Netherlands
  • T.F. Fujita
    National Institute of Radiological Sciences, Chiba, Japan
  • T. Sakuma, N. Sasaki, T. Sasano, W. Takasugi
    AEC, Chiba, Japan
  
  Since 1994, heavy-ion radiotherapy using carbon ions is successfully carried out with the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). Over 5000 cancer patients have already been treated with 140-400 MeV/u carbon beams. These clinical results have clearly verified the advantages of carbon ion. The ion source needs to realize a stable beam with the same conditions for daily operation. Maintenance is restricted to once per year. However, the deposition of carbon on the wall of the plasma chamber is normally unavoidable. This causes an ‘anti-wall-coating effect’, i.e. a decreasing of the beam (typically 50 % after a few months of operation), especially for the higher charge-state ions due to the surface material of the wall. The ion source has - even in this bad condition – still to produce a sufficiently intense and stable beam. We summarize our experience during 16 years of operation and show the scope for further developments. HIMAC is dedicated to radiotherapy, but it has as a second essential task to operate as a facility for physicist users. In that scope it accelerates many ion species for basic experiments. In order to serve all HIMAC users at best, the extension of the range of ion species is an important subject in ion source development. For example, in order to increase the ECRIS-beam intensity for heavier ions, microwave is applied at different frequencies by a traveling wave tube amplifier and….?  
slides icon Slides MOCOBK03 [2.780 MB]  
 
MOCOBK04 Recent Activities at the ORNL Multicharged Ion Research Facility (MIRF) ion, ECR, electron, permanent-magnet 23
 
  • F.W. Meyer, M.E. Bannister, S. Deng, I.N. Draganić, J.W. Hale, P.R. Harris, C.C. Havener, H.F. Krause, C.R. Vane
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: Sponsored by the Office of Fusion Energy Sciences and the Office of Basic Energy Sciences of the U.S. DOE under contract No. DE-AC05-00OR22725 with UT_Battelle.
We report on recent upgrades of the ORNL Multicharged Ion Research Facility, and our activities in the area of ECR ion source diagnostic measurements. The upgrades include installation of a new all permanent magnet ECR ion source [1] on a high voltage platform that increases our high energy beam production capability to 250keV/q, and installation of a floating beamline fed by a 10 GHz CAPRICE ECR ion source for producing decelerated ion beams to energies as low as a few eV/q range. The primary application of all the produced ion beams is to study fundamental collisional interactions [2] of multicharged ions with electrons, atoms, and surfaces. We also summarize recent diagnostic measurements of the ECR plasma potential and other plasma parameters using an in-situ Langmuir probe installed in the ECR edge plasma and complementary measurements [3] using an external beam deceleration method.
[1] D. Hitz et al. , “An All-Permanent Magnet ECR Ion Source for the ORNL MIRF Upgrade Project,” AIP Conference Proceedings 749, 123 (2005), Woodbury, NY.
[2] F.W. Meyer, “ECR-Based Atomic Collision Physics Research at ORNL MIRF,” in Trapping Highly Charged Ions: Fundamentals and Applications, J. Gillaspy, ed., Nova Science Pub., New York, 2000, pp. 117-164.
[3] P.R. Harris and F.W. Meyer, Rev. Sci. Inst. 81, 02A310 (2010). 		 
slides icon Slides MOCOBK04 [2.645 MB]  
 
MOCOCK02 3D Simulation Studies and Optimization of Magnetic Holes of HTS-ECRIS for Improving the Extraction Efficiency and Intensities of Highly Charged Ions ion, ECR, extraction, ion-source 27
 
  • G. Rodrigues, R.N. Dutt, D. Kanjilal, P.S. Lakshmy, Y. Mathur, U.K. Rao, A. Roy
    IUAC, New Delhi, India
  • R. Baskaran
    IGCAR, Channai, India
  
  3D simulation studies using RADIA code have been performed to optimise the magnetic holes in high temperature superconducting electron cyclotron resonance (HTS-ECRIS) ion source for improving the extraction efficiency and intensities of highly charged ions. The magnetic field improvements using simple techniques like optimisation of iron regions is found to be economical. The extraction efficiency can be increased three-fold in the case of a hexapole magnet depending on the level of the uniformity of the fields in the high and low regions. This technique further minimises localized heating of the plasma chamber walls which can improve the vacuum conditions in an ECR ion source. For superconducting sources where the x-ray heat load poses severe problems during operation, such a reduction of heating load is of great significance. The typical triangular pattern of the plasma impact observed on the plasma electrode of HTS ECRIS at various tuning conditions are reproduced by the simulations. Details of the simulations and experimental results will be presented.  
slides icon Slides MOCOCK02 [2.925 MB]  
 
MOCOCK03 Design Study of a Higher Magnetic Field SC ECRIS at IMP ECRIS, solenoid, sextupole, ion 30
 
  • D. Xie, W. Lu, X.Z. Zhang, H.W. Zhao
    IMP, Lanzhou, People's Republic of China
  
  Development of ECR ion source has demonstrated that, as the empirical scaling laws summarized, higher magnetic field with higher operation frequencies will greatly improve the source performance. Based on the great success of SECRAL, a higher magnetic field SC ECRIS is planned to meet the new accelerator demands at IMP. However, there are many practical issues in the design and construction of a higher field SC ECRIS that need to be addressed. In this paper we will present and discuss the design features of the higher field SC ECR with a maximum axial field of 7.0 T and a radial field of 3.5 T at the plasma chamber inner surface, and operating frequency up to 50 GHz.  
slides icon Slides MOCOCK03 [1.825 MB]  
 
MOCOCK05 Multigan®: a New Multicharged Ion Source Based on Axisymetric Magnetic Structure ion, ECRIS, electron, extraction 37
 
  • L. Maunoury, P. Delahaye, M. Dubois, P. Jardin, P. Lehérissier, M. Michel, J.Y. Pacquet
    GANIL, Caen, France
  • S. Biri
    ATOMKI, Debrecen, Hungary
  • X. Donzel, G. Gaubert, R. Leroy, A.C.C. Villari
    PANTECHNIK, BAYEUX, France
  • C. Pierret
    CIMAP, Caen, France
  
  Standard ECR ion sources have radial magnetic field created by a multi-pole, e.g. hexapole or higher order, which fills all space in the center of the source structure. Based on the Monogan® ECRIS [1] concept, a new multicharged ECR ions source has been designed with a large opening space in the center of the source structure. This particular design allows, in a first approach, direct radial contact with the ECR plasma, allowing positioning of probes and targets for radioactive beam production very close to the plasma region. Secondly, the absence of a multi-pole allows considering extremely high magnetic fields with significantly smaller structural constraints. This source is combining the advantages of the axisymetric magnetic feature of Monogan® with higher frequencies. This paper will describe the magnetic structure calculation as well as the mechanical design and stresses of a full permanent magnet ion source using this concept. This source will be the first prototype of such an ECR ion source. Finally, using TrapCad code [2], an estimation of the electronic energy distribution has been calculated and thus, the performance of the source has been deduced. The beam formation and extraction were also roughly calculated taking into account magnetic and electric fields.
[1] P. Jardin et al., Review of Scientific Instruments, 73, 789 (2002).
[2] L. Maunoury et al., Plasma Sources Science and Technology , 18, 015019 (2009). 		 
slides icon Slides MOCOCK05 [5.532 MB]  
 
MOPOT002 Two-Chamber Configuration of the Bio-Nano ECRIS ion, ECRIS, extraction, resonance 43
 
  • T. Uchida, H. Minezaki, Y. Yoshida
    Toyo University, Kawagoe-shi, Saitama, Japan
  • T. Asaji, K. Tanaka
    Tateyama Machine Co. Ltd., Toyama-shi, Japan
  • S. Biri, R. Rácz
    ATOMKI, Debrecen, Hungary
  • Y. Kato
    Osaka University, Graduate School of Engineering, Osaka, Japan
  • A. Kitagawa, M. Muramatsu
    NIRS, Chiba-shi, Japan
  
  The Bio-Nano ECRIS was designed for new materials production on nano-scale [1]. Our main target is the endohedral fullerene, which have potential in medical care, biotechnology and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. There are several promising approaches to produce the endohedral fullerenes using an ECRIS. One of them is the ion-ion collision reaction of fullerenes and aliens ions to be encapsulated in the mixture plasma of them. Another way is the shooting of ion beam into a pre-prepared fullerene layer. In this study, the new device configuration of the Bio-Nano ECRIS is reported which allows the application of both methods. The plasma chamber is divided into two chambers by installing mesh electrodes. In the gas injection-side 1st chamber at 2.45 GHz plasmas (N2, Ar, He, Fe,…) are produced on the usual way. These ions then are extracted to the 2nd chamber where an evaporation boat for fullerene is installed. The fullerene neutrals can be ionized (using 10 GHz in the 2nd chamber) and are deposited on a large plasma electrode where they are continuously irradiated by the ions from the 1st chamber. The ions produced either in the 1st or 2nd chamber can be in-situ extracted and analyzed. The basic concept and the preliminary results using Ar gas and N2 gas plasmas will be presented.
[1] T. Uchida et al., Proc. ECRIS08, Chicago, USA, pp. 27-31 (2008) 		 
poster icon Poster MOPOT002 [6.248 MB]  
 
MOPOT003 Study of Potential Application of Compact ECRIS to Analytical System ion, ECR, ion-source, permanent-magnet 46
 
  • M. Kidera
    RIKEN Nishina Center, Wako, Japan
  • S. Enomoto
    Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
  • S. Kishi, Y. Seto
    National Research Institute of Police Science, Chiba, Japan
  • T. Nagamatsu, T. Tanaka
    Tokyo University of Science, Faculty of Engineering Division I, Tokyo, Japan
  • K. Takahashi
    RIKEN, Saitama, Japan
  
  A place of an activity of ECR ion sources is not only ion source on a heavy ion accelerator facility. A highly ionization efficiency, flexibility of ionized sample, low consumption rate in sample, and non-equilibrium ECR plasma, etc. that a ECR ion source have, may be needed in other fields at time. We have developed several kinds of small ECRISs that have customized for the analysis. The purposes of the analysis are, precise measurement of isotope ratio of a metal element, detection of chemical warfare agents, and detection of produced molecular (or fragment) ions by the ECR plasma. In this workshop, we will report the compact ECRISs by a permanent magnet type for the analytical system.  
poster icon Poster MOPOT003 [3.320 MB]  
 
MOPOT005 High Current Production with 2.45 GHz ECR Ion Source ion, extraction, ECR, ion-source 50
 
  • A. Coly, T. Lamy, T. Thuillier
    LPSC, Grenoble Cedex, France
  • G. Gaubert, A.C.C. Villari
    PANTECHNIK, BAYEUX, France
  
  A new test bench has been installed at LPSC dedicated to 2.45 GHz ECR Ion Sources characterization. Several magnetic structures have been tested around the same plasma cavity. For example, a current density of 70 mA/cm2 has been measured with the MONO1000 source lent by GANIL. An original ECRIS, named SPEED (for 'Source d'ions à aimants PErmanents et Extraction Dipôlaire'), presenting a dipolar magnetic field at the extraction will also be presented.  
poster icon Poster MOPOT005 [3.130 MB]  
 
MOPOT006 Ionization Efficiency of a COMIC Ion Source Equipped With a Quartz Plasma Chamber ion, ion-source, target, injection 51
 
  • P. Suominen, T. Stora
    CERN, Geneva, Switzerland
  • J. Médard, P. Sortais
    LPSC, Grenoble, France
  
  The ISOLDE facility at CERN produces a wide range of radioactive ion beams due to a long history on target and ion source development. Because the radioactive isotope production is very limited, the most important ion source parameters are high ionization efficiency, selectivity and reliable operation under intense radiation. Currently used ion sources (mainly laser (RILIS [1]) and arc discharge -type ion sources (VADIS [2]) do not efficiently ionize light noble gases, such as helium, and molecules, such as CO, N2 and NO. These beams were previously planned to be produced with 1+ ECR ion sources operating at 2.45 GHz (for example MINIMONO [3]) but due to new and more efficient RF coupling of COMIC-type ion sources [4], we expect to advance in 2.45 GHz ECRIS utilization for radioactive beam production. The new COMIC source designed by LPSC, Grenoble incorporates special features such as a plasma chamber fully made of quartz (Q-COMIC). This should provide chemically good conditions for molecular ion beam production, especially for carbon. This paper presents the first ionization efficiency measurements of the Q-COMIC.
[1] V.N. Fedosseev, et al, Nucl. Instrum. Methods Phys. Res. B 266/19-20 (2008) 4378.
[2] PhD thesis, univ. polyt. Bucarest, L. Penescu (2009).
[3] F. Wenander, W. Farabolini, G. Gaubert, P. Jardin, J. Lettry, Nucl. Phys. A, 746 (2004) 659.
[4] P. Sortais, T. Lamy, J. Médard, J. Angot, L. Latrasse, and T. Thuillier, Rev. Sci. Instrum. 81 (2010) 02B314. 		 
poster icon Poster MOPOT006 [0.697 MB]  
 
MOPOT008 He2+ Source Based on Penning Discharge with Additional 75 GHz ECR Heating ECR, ion, radiation 54
 
  • A. Vodopyanov, S. Golubev, I. Izotov, A. Mansfeld
    IAP/RAS, Nizhny Novgorod, Russia
  • G. Yushkov
    Institute of High Current Electronics, Tomsk, Russia
  
  It is well known that one can reach high average charge of ions in the ECR plasma by increasing plasma density and decreasing neutral gas pressure. ECR discharge could be realized at very low gas pressure, but discharge startup takes longer time when gas pressure is low. So, it is impossible to realize ECR discharge with limited microwave heating pulse duration at gas pressure lower certain threshold value. This problem could be solved with help of trigger plasma, which should be ignited at low gas pressure in the trap with high magnetic field. This fore plasma could help to decrease ECR plasma startup time significantly and make it possible to realize ECR plasma at very low pressure in pulse operation regime. We suggest penning type discharge as a trigger discharge for fast startup of pulsed ECR plasma. Penning type discharge glows at as low pressure as needed. Discharge was realized in the simple mirror magnetic trap at pressure about 10-5 mbar. Helium was used as an operating gas. Significant plasma density (about 1011 cm-3) was obtained at the moment just before microwave heating pulse started. Gyrotron radiation with frequency of 75 GHz, microwave power up to 200 kW and pulse duration up to 1 ms, was used for plasma heating. In the present work the fully striped helium ions were demonstrated, average charge of ions in the plasma was equal 2. Temporal evolution of charge state distribution was investigated. Charge state distribution over helium pressure was also studied.  
poster icon Poster MOPOT008 [0.535 MB]  
 
MOPOT010 The Light Ion Guide CB-ECRIS Project at the Texas A&M University Cyclotron Institute ion, ECRIS, cyclotron, light-ion 55
 
  • G. Tabacaru
    Texas A&M University, Cyclotron Institute, College Station, USA
  • J. Ärje
    JYFL, Jyväskylä, Finland
  • D.P. May
    Texas A&M University Cyclotron Institute, College Station, Texas, USA
  
  Texas A&M is currently configuring a scheme for the production of radioactive-ion beams that incorporates a light-ion guide (LIG) coupled with an ECRIS constructed for charge-boosting (CB-ECRIS). This scheme is part of an upgrade to the Cyclotron Institute and is intended to produce radioactive beams suitable for injection into the K500 superconducting cyclotron. The principle of operation is the following: a primary beam from the K150 cyclotron interacts with a production target placed in the gas cell. A continuous flow of helium gas maintains a constant pressure of 500 mbar maximum in the cell. Recoils are thermalized in the helium buffer gas and ejected from the cell within the gas flow through a small exit hole. The positively charged recoil ions (1+) are guided into a 2.5 m long, rf-only hexapole and will be transported in this manner on-axis into the CB-ECRIS. The CB-ECRIS operates at 14.5 GHz and has been specially constructed by Scientific Solutions of San Diego, California for charge-boosting. An overview of the entire project will be presented with details on different construction phases. Specific measurements and results will be presented as well as future development plans.  
poster icon Poster MOPOT010 [12.413 MB]  
 
MOPOT011 DRAGON: a New 18 GHz RT ECR Ion Source with a Large Plasma Chamber ECRIS, sextupole, extraction, injection 58
 
  • W. Lu, D. Xie, X.Z. Zhang, H.W. Zhao
    IMP, Lanzhou, People's Republic of China
  • W. Lu
    Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China
  • L. Ruan, F.C. Song, B. Xiong, S. Yu, J. Yuan
    IEE, Beijing, People's Republic of China
  
  Building a strong radial magnetic field with a permanent hexapole magnet for an ECRIS is extremely challenging so that the conventional wisdom requires a small but not optimal plasma chamber that is typically of ID less or equal to 80 mm. A new 18 GHz RT ECR ion source, DRAGON, has been designed with a large bore permanent hexapole and source construction has begun at IMP. Its plasma chamber is of ID of 126 mm, the same as that of the superconducting ion source SECRAL, with maximum radial field strength reaching 1.5 Tesla at the plasma chamber wall. The overall magnetic strengths of DRAGON, with maximum axial fields of 2.7 Tesla at the injection and 1.3 Tesla at the extraction, are very similar to those of SECRAL operating at 18 GHz and hopefully the SECRAL performance. The source solenoid magnet coils are cooled by an evaporative coolant at about 50 degree C. In addition, the source is thickly insulated for beam extraction at 50 kV and higher voltage up to 100 kV can be explored. This article will present the design details and discussions of this new ion source.  
poster icon Poster MOPOT011 [0.563 MB]  
 
MOPOT012 Tests of the Versatile Ion Source (VIS) for High Power Proton Beam Production emittance, extraction, permanent-magnet, proton 61
 
  • S. Gammino, G. Castro, L. Celona, G. Ciavola, D. Mascali, R. Miracoli
    INFN/LNS, Catania, Italy
  • G. Adroit, O. Delferrière, R. Gobin, F. Senée
    CEA/DSM/IRFU, France
  • F. Maimone
    GSI, Darmstadt, Germany
  
  The sources adapted to beam production for high power proton accelerators must obey to the request of high brightness, stability and reliability. The Versatile Ion Source (VIS) is based on permanent magnets (maximum value around 0.1 T on the chamber axis) producing an off-resonance microwave discharge. It operates up to 75 kV without a bulky high voltage platform, producing several tens of mA of proton beams and monocharged ions. The microwave injection system and the extraction electrodes geometry have been designed in order to optimize the beam brightness. Moreover, the VIS source ensures long time operations without maintenance and high reliability in order to fulfil the requirements of the future accelerators. A description of the main components and of the source performances will be given. A brief summary of the possible options for next developments of the project will be also presented, particularly for pulsed mode operations, that are relevant for some future projects (e.g. the European Spallation Source of Lund).  
 
MOPOT013 MONOBOB II : Latest Results of Monocharged Ion Source for SPIRAL2 Project target, ion, ECRIS, vacuum 64
 
  • M. Dubois, O. Bajeat, C. Barue, C. Canet, M. Dupuis, J.L. Flambard, R. Frigot, P. Jardin, C. Leboucher, N. Lecesne, P. Lecomte, P. Lehérissier, F. Lemagnen, L. Maunoury, O. Osmond, J.Y. Pacquet, A. Pichard
    GANIL, Caen, France
  
  MONOBOB II is an electron cyclotron resonance ion source (ECRIS) based on a cylindrical symmetry magnetic structure [1]. It has been designed for the SPIRAL2 project in order to ionize radioactive gases coming from the production targets of the Target Ion Source System (TISS). The goal is to build a long-lived ECRIS with the aim of running three months in the hostile environment of the production target while keeping high ionization efficiencies. The Target Ion Source System has been tested using noble gases (He, Ne, Ar, Kr and Xe), with and without target in order to observe the behavior of the source coupled to the target. Currently, the target is made of ~1000 carbon slices, having the same geometry as the final UCx target. So far, its temperature has been limited to 1500°C. Ionization efficiencies and response times of the TISS have been measured versus gases and target temperature [2]. Results should lead to determine the maximum radioactive ion production which can be reasonably expected with the final TISS. The status of this development will be presented.  
poster icon Poster MOPOT013 [0.858 MB]  
 
MOPOT016 A Low Power Survey of Radial-Offset Axial Sputtering and High Intensity Uranium Production from Axial Sputtering in SuSI target, injection, survey, ion 69
 
  • D.G. Cole, G. Machicoane, T. Ropponen, L.T. Sun, L. Tobos
    NSCL, East Lansing, Michigan, USA
  
  Prototype sputtering hardware has been tested in the SuSI ion source and early uranium ion production is discussed. Also, results of a low power survey of axial sputtering, to test sputtering efficiency at incremental radial offsets from on axis position, is reported.  
poster icon Poster MOPOT016 [2.672 MB]  
 
MOPOT017 Tests of a New Axial Sputtering Technique in an ECRIS ECRIS, ECR, ion, injection 72
 
  • R.H. Scott, R.C. Pardo, R.C. Vondrasek
    ANL, Argonne, USA
  
  Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357.
Axial and radial sputtering techniques have been used over the years to create beams from an ECRIS at multiple accelerator facilities. Operational experience has shown greater beam production when using the radial sputtering method versus axial sputtering. At Argonne National Laboratory, previous work with radial sputtering has demonstrated that the position of the sputter sample relative to the plasma chamber wall influences sample drain current, beam production and charge state distribution. The possibility of the chamber wall acting as a ground plane which influences the sputtering of material has been considered, and an attempt has been made to mimic this possible ground plane effect with a coaxial sample introduced from the injection end. Results of these tests will be shown as well as comparisons of outputs using the two methods. 		 
poster icon Poster MOPOT017 [1.506 MB]  
 
TUCOBK01 Preglow Phenomenon Origins and its Scaling for Ecris radiation, ion, electron, ECR 87
 
  • I. Izotov, V. Sidorov, V. Skalyga, V. Zorin
    IAP/RAS, Nizhny Novgorod, Russia
  
  Preglow effect investigation is one of topical directions of ECR ion sources development at present. Preglow is of interest for efficient short-pulsed multi-charged ion source creation. Particularly, such source of intense beams of short-living radioactive isotopes multi-charged ions is one of key elements in “Beta-Beam” European project [1]. Use of Preglow-generating regime of an ECRIS operation is a promising way of pulsed high-intense multi-charged ion beams production with much shorter edges in comparison with usual operation regime. The first theoretical investigations of Preglow phenomenon were performed in references [2,3]. Present work describes modified model of ECR discharge development in a magnetic trap of the ECRIS as a continuation of [2,3]. Numerical simulations made with the updated model allow authors to propose more physical and intuitive explanation of Preglow phenomenon origins. Obtained dependences of Preglow characteristics on experimental conditions offer a scaling for a wide range of ECRISes.
[1] (ONLINE) http://beta-beam.web.cern.ch/beta-beam/task/diverse/mandate.htm
[2] T. Thuillier et al, Rev. of Sci. Instrum., 79, 02A314, 2008.
[3] I. Izotov et al, IEEE Trans. Plasma Sci. 36, 1494, 2008. 		 
slides icon Slides TUCOBK01 [0.928 MB]  
 
TUCOBK02 “Preglow” Investigation in ECR Discharge at 37 GHz, 100 kW ion, ECR, ion-source, radiation 90
 
  • V. Skalyga, I. Izotov, S. Razin, V. Sidorov, V. Zorin
    IAP/RAS, Nizhny Novgorod, Russia
  • T. Lamy, T. Thuillier
    LPSC, Grenoble, France
  
  Multicharged ion beams generation in "Preglow" regime is now considered as the main way of short pulsed ion source creation for “Beta Beam” project. The "Preglow" effect has been investigated at a several laboratories (LPSC, JYFL, IAP RAS). The effect was discovered at LPSC on PHOENIX ion source using 18 GHz radiation for plasma heating. Investigations at 14 GHz frequency were made at JYFL. Theoretical analysis demonstrated the advantage of MW frequency increase. Theoretical calculations predict possibility of "Preglow" peaks generation with duration about tens microseconds and rather high average ion charge. At present time at LPSC a joint construction of a new generation ECR ion source with 60 GHz gyrotron plasma heating is running. As a continuation of previous research at 14, 18 and 28 GHz at present work results of experimental and theoretical "Preglow" effect investigations at SMIS 37 setup with 37,5 GHz MW plasma heating are reported. Received data are important as fundamental result in physics of ECRISs and at the same time it is the next step on the way of 60 GHz SEISM facility creation. “Preglow” effect was observed and investigated in experiments with ECR discharge stimulated with gyrotron radiation @ 37.5 GHz, 100 kW. Received dependencies of the “Preglow” parameters are in good correspondence with results of numerical simulations. It was shown in experiments that generation of “Preglow” peak with duration about 30 μs is possible.  
slides icon Slides TUCOBK02 [2.338 MB]  
 
TUCOBK03 Time Evolution of Plasma Potential in Pulsed Operation of ECRIS ion, electron, ion-source, ECRIS 93
 
  • O.A. Tarvainen, H. A. Koivisto, T. Ropponen, V.A. Toivanen
    JYFL, Jyväskylä, Finland
  • Y. Higurashi, T. Nakagawa
    RIKEN Nishina Center, Wako, Japan
  
  The time evolution of plasma potential has been measured in pulsed operation mode with electron cyclotron resonance ion sources at JYFL and RIKEN. Three different ion sources with microwave frequencies ranging from 6.4 to 18 GHz were employed for the experiments. The plasma potential during the preglow and afterglow transients was compared with steady state conditions. The plasma potential was observed to increase 25-75 % during the preglow and 10-30 % during the afterglow. We describe the experimental procedure and present the results of the study in detail.  
slides icon Slides TUCOBK03 [0.973 MB]  
 
TUCOBK04 Micropulses Generation in ECR Breakdown Stimulated by Gyrotron Radiation at 37.5 GHz ion, ECR, electron, ion-source 96
 
  • V. Skalyga, S. Golubev, I. Izotov, S. Razin, V. Sidorov, A. Vodopyanov, V. Zorin
    IAP/RAS, Nizhny Novgorod, Russia
  
  Present work is devoted to experimental and theoretical investigation of possibility of short pulsed (< 100 μs) multicharged ion beams creation. The possibility of quasi-stationary generation of short pulsed beams under conditions of quasi-gasdynamic plasma confinement was shown in recent experiments. Later another way of such beams creation based on “Preglow” effect was proposed. In present work it was demonstrated that in the case when duration of MW pulse is less then formation time of “Preglow” peak, realization of a regime when ion current is equal to zero during MW pulse and intense multicharged ions flux appears only when MW ends could be possible. Such pulses after the end of MW were called "micropulses". In present work generation of micropulses was observed in experiments with ECR discharge stimulated by gyrotron radiation @ 37,5GHz, 100 kW. In this case pulses with duration less than 30 μs. Probably the same effect was observed in GANIL where 14 GHz radiation was used and pulses with duration about 2 ms were registered. In present work it was shown that intensity of such micropulse could be higher than intensity of “Preglow” peak at the same conditions but with longer MW pulse. The generation of micropulses of nitrogen and argon multicharged ions with current of a few mA and length about 30 μs after MW pulse with duration of 30-100 μs was demonstrated. The low level of impurities, high current density and rather high average charge make possible to consider such micropulse regime as perspective way for creation of a short pulsed ion source.  
slides icon Slides TUCOBK04 [3.473 MB]  
 
TUCOCK01 Beam, Multi-Beam and Broad Beam Production with COMIC Devices cavity, extraction, ion, high-voltage 99
 
  • P. Sortais, J. Angot, T. Lamy, J. Médard
    LPSC, Grenoble Cedex, France
  • C. Peaucelle
    IN2P3 IPNL, Villeurbanne, France
  
  The COMIC discharge cavity is a very versatile technology. We will present new results and devices that match new applications like: molecular beams, ultra compact beam line for detectors calibrations, quartz source for on-line application, high voltage platform source, sputtering /assistance broad beams and finally, a quite new use, high energy multi¬-beam production for surface material modifications. In more details, we will show that the tiny discharge of COMIC can mainly produce molecular ions (H3+). We will present the preliminary operation of the fully quartz ISOLDE COMIC version, in collaboration with IPN-Lyon, we will present a first approach for a slit extraction version of a three cavity device, and after discussing about various extraction systems on the multi discharge device (41 cavities) we will show the low energy broad beam (2 KV) and high energy multi-beams (10 beams up to 30 KV) productions. We will specially present the different extraction systems adapted to each application and the beams characteristics which are strongly dependent on the voltage distribution of an accel-accel two electrodes extraction system.  
slides icon Slides TUCOCK01 [4.960 MB]  
 
TUCOCK02 Status of the High Current Permanent Magnet 2.45 GHz ECR Ion Source at Peking University ion, ion-source, ECR, extraction 102
 
  • S.X. Peng, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.R. Lu, H.T. Ren, Z.Z. Song, J.X. Yu, Z.X. Yuan, M. Zhang, J. Zhao
    PKU/IHIP, Beijing, People's Republic of China
  
  Several compact 2.45 GHz Electron Cyclotron Resonance Ion Sources (ECRIS) have been developed at Peking University for ion implantation[1], separated function Radio Frequency quadruple (SFRFQ)[2] and for the Peking University Neutron Imaging Facility (PKUNIFTY)[3]. Studies are focused on methods of magnetic field generation, magnetic fields configuration, microwave window design, microwave coupling, and structure selection of extraction electrodes. Up to now, our sources have produced 25 mA O+/ He+ ion, 10mA N+ ion, 100 mA H+ and 83 mA D+ ions, respectively. Details will be reported in the paper.
[1] Z. Song, D. Jiang, and J. Yu, Rev. Sci. Instr., 67,1003(1996).
[2] S. X. Peng, M. Zhang, Z. Z. Song, R. Xu, J. Zhao, Z. X. Yuan, J. X. Yu, J. Chen, Z. Y. Guo, Rev. Sci. Instr., 2008, 79: 02B706.
[3] M. Zhang, S. X. Peng, H. T. Ren, Z. Z. Song, Z. X. Yuan, Q. F. Zhou, P. N. Lu, R. Xu, J. Zhao, J. X. Yu, J. E. Chen, Z. Y. Guo, and Y. R. Lu, Rev. Sci. Instr. 2010, 81:02B715. 		 
slides icon Slides TUCOCK02 [3.144 MB]  
 
TUCOCK03 Development of 14.5 GHz Electron Cyclotron Resonance Ion Source at KAERI ECR, ion, ion-source, extraction 105
 
  • B.H. Oh, D.S. Chang, C.K. Hwang, S.R. In, S.H. Jeong, J.T. Jin, K.W. Lee, C.S. Seo
    KAERI, Daejon, Republic of Korea
  
  A 14 GHz ECRIS has been designed and fabricated in KAERI (Korea Atomic Energy Research Institute) to produce multi-charged ion beam (especially for C6+ ion beam) for medical applications. The magnet system has solenoid coils made with copper conductor and a hexapole made with permanent magnet. The solenoid coils are composed of two axial coils to make mirror fields in both sides of the chamber and one trim coil at the center to control the layer of the resonance region. The hexapole is made with 24-sector NdFeB permanent magnet. Radial field higher than 1.2 T at the chamber wall position has been measured, and axial field higher than 1.7 T at the entrance center of RF power and 1.1 T at the exit center of ion beam have been measured. A welded tube with aluminum and stainless steel is used for a ECR plasma chamber to improve the production of secondary electron. Cooling channel is made on the wall of the Al tube. A 2 kW Krystron is used as a microwave energy source. A DC break made with PEEK(Polyether Ether Ketone) for high voltage insulation and field shielding, and a RF window made with ceramic for vacuum insulation are inserted in the RF circuit. A movable beam extractor with 8 mm aperture covers different species and different charge numbers of the beam. Experimental results on ECR plasma and initial beam extraction with KAERI ECR ion source will be discussed.  
slides icon Slides TUCOCK03 [2.342 MB]  
 
TUPOT002 Enhancement of ECR Performances by Means of Carbon Nanotubes Based Electron Guns electron, gun, ion, ECR 114
 
  • F. Odorici, M. Cuffiani, L. Malferrari, R. Rizzoli, G.P. Veronese
    INFN-Bologna, Bologna, Italy
  • G. Castro, L. Celona, G. Ciavola, N. Gambino, S. Gammino, D. Mascali, R. Miracoli, F.P. Romano
    INFN/LNS, Catania, Italy
  • T. Serafino
    Università di Messina, Messina, Italy
  
  One of the main goals of the scientific community which deals with ECR Ion Sources is the optimization of the Eelectron Energy Distribution Function (EEDF) inside the plasma. The EEDF consists of three different populations (cold, warm and hot electrons): the cold and the warm populations are responsible of the stabilization and of the efficient ionization of the plasma respectively. The presence of the hot population is doubly detrimental: in high frequency sources they lead to the heating of LHe in the superconducting coils’ cryostat and are also useless for the generation of high intensity ion beams, because of their small cross section. Therefore the injection of additional electrons inside the plasma may increase the density of cold and warm electrons, enabling at the same time to reduce the number of the high energy ones. The CANTES experiment tested the use of carbon nanotubes (CNTs) to emit electrons in presence of strong applied electric fields, in order to provide additional electrons to the plasma core. This technique was used with the Caesar ECR ion source, at INFN-LNS, demonstrating that the total extracted ion current is increased and that a relevant reduction of the number of “high energy” electrons (above 100 keV) can be obtained. This last result is even more important, because CNTs may be an effective and reliable tool to permit the operation of ECRIS at large power and high frequencies without any detrimental effect on the source stability and reliability coming from hot electrons. Details of the construction of CNTs based electron gun and their behaviour in plasma environments are presented. Preliminary results in terms of performances of the Caesar ECR ion source and possible future applications will be also discussed.  
poster icon Poster TUPOT002 [1.914 MB]  
 
TUPOT003 A New BETSI Test Bench at CEA/Saclay permanent-magnet, ion, diagnostics, solenoid 117
 
  • S. Nyckees, Y. Gauthier, C.M. Mateo
    CEA/IRFU, Gif-sur-Yvette, France
  • G. Adroit, O. Delferrière, R.D. Duperrier, R. Gobin, F. Harrault, O. Napoly, B. Pottin, Y. Sauce, F. Senée, O. Tuske, T.V. Vacher
    CEA/DSM/IRFU, France
  
  By the 90s, CEA has undertaken to develop the production of high intensity light ion beams from plasma generated by electron cyclotron resonance (ECR). Important results were obtained with the SILHI source in pulsed or continuous mode. Presently, CEA/Saclay is now involved in the construction of different injectors dedicated to large infrastructures like IFMIF or Spiral 2. Other installations are also interested by high intensity ion sources like ESS or FAIR. To improve and test new sources, a new test bench named BETSI (Banc d'Etudes et de Tests des Sources d'Ions) is now operating for several months. Low energy beam line diagnostics consist of a Faraday cup, cameras and a species analyzer. The SILHI emittance scanner can also be installed on the beam line. On this test bench, different permanent magnet source configurations are tested. In order to modify plasma chamber size and shape, a new ECR source design is developed. An experimental study of the plasma visible light emitted through electrodes was implemented on BETSI using a monochromator. Extracted beam intensity of a permanent magnet source is compared to plasma light emission. Results obtained with monochromator will be compared with SOLMAXP code in order to explore radio frequency wave and plasma interaction.  
poster icon Poster TUPOT003 [4.044 MB]  
 
TUPOT005 An ECR Table Plasma Generator ECR, ECRIS, ion, vacuum 124
 
  • R. Rácz, S. Biri
    ATOMKI, Debrecen, Hungary
  • J. Pálinkás
    DU, Debrecen, Hungary
  
  A simple ECR plasma device was built in our lab using the “spare parts” of the ATOMKI ECR ion source. We call it “ECR table plasma generator”. It consists of a relatively big plasma chamber (ID=10 cm, L=40 cm) in a thin NdFeB hexapole magnet with independent vacuum and gas dosing systems. For microwave coupling two low power TWTAs can be applied individually or simultaneously, operating in the 6-18 GHz range. There is no axial magnetic field and there is no extraction. The intended fields of usage of the plasma generator are:
  1. A simple, cheap and safe educational working place for students.
  2. To prepare, to test or to simulate measurements with electrostatic movable Langmuir probes. The exchange time of the (damaged) probes is very short.
  3. To prepare, to test or to simulate plasma diagnostic measurements in the visible light and X-ray ranges using cameras and spectrometers.
  4. To cover and/or to modify solid surfaces with plasma particles, including fullerenes.
In the paper the technical details of the plasma generator and some preliminary plasma photo results are shown. 		 
poster icon Poster TUPOT005 [0.871 MB]  
 
TUPOT007 Preliminary Design of BLISI, an Off Resonance Microwave Proton Source ion, extraction, proton, resonance 130
 
  • S. Djekic, I. Bustinduy, D. Cortazar, D. Fernandez-Cañoto, H. Hassanzadegan, J.L. Munoz, D. de Cos
    ESS Bilbao, Bilbao, Spain
  • F.J. Bermejo
    Bilbao, Faculty of Science and Technology, Bilbao, Spain
  • M.A. Carrera, J.H. Galipienzo
    AVS, Eibar, Gipuzkoa, Spain
  • V. Etxebarria, J. Jugo, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  • J. Feuchtwanger, I. Rueda
    ESS-Bilbao, Zamudio, Spain
  • J. Lucas
    Elytt Energy, Madrid, Spain
  
  A new high current off resonance microwave H+ source is currently in the last stages of design at ESS-Bilbao, in collaboration with two external companies Elytt and AVS. The design is intended to be a high-stability, high-current ion source capable of delivering a 70 mA proton beam with a 70 keV energy at the end of the extraction. The plasma system designed by Elytt consists of a water-cooled plasma chamber that sits between two independently powered magnetic coils that generate the ECR magnetic field; in addition they can be moved independently to further shape the magnetic field in the chamber. A CPI 2.7 GHz klystron provides the microwave energy and a fully controlled microwave system to minimize reflected power and improve the source overall performance is also under construction. The extraction column designed by AVS will consist of a movable tetrode system designed for a maximum acceleration potential of 70 kV, the shape of the electrodes is at an earlier design stage at ESS-Bilbao. We will present the current layout of the source, simulations and schematics of the source.  
poster icon Poster TUPOT007 [3.954 MB]  
 
TUPOT008 Performance of the LBNL AECR-U with a TWTA ion, resonance, coupling, ion-source 133
 
  • J.Y. Benitez, D. Leitner, C.M. Lyneis
    LBNL, Berkeley, California, USA
  • M.K. Covo
    LLNL, Livermore, California, USA
  
  The Advanced Electron Cyclotron Resonance - Upgrade ion source (AECR-U) at the Lawrence Berkeley National Laboratory has successfully utilized double frequency microwave heating (14.3 GHz and 10.4 GHz) for several years [1]. Recently a traveling wave tube amplifier (TWTA), providing frequencies in the range of 10.75GHz-12.75GHz, was added as a secondary heating frequency, replacing the previous 10.4 GHz Klystron. The TWTA opens the possibility to explore a wide range of secondary frequencies and a study has been conducted to understand and optimize its coupling into the AECR-U. In particular, the reflected power dependence on heating frequency has been mapped out with and without the presence of plasma. A comparison is made to determine how the presence of plasma, confinement fields, and other source parameters affect the reflected power and if and how the amount of reflected power can be correlated to the source ion beam performance.
[1] Z. Q. Xie and C. M. Lyneis, Rev. Sci. Instrum. 66 (1995). 		 
poster icon Poster TUPOT008 [0.213 MB]  
 
TUPOT009 Measurements of Bremsstrahlung Radiation and X-Ray Heat Load to Cryostat on SECRAL radiation, ion, electron, ECR 134
 
  • H. Zhao, Y. Cao, X.X. Li, D. Xie, W.H. Zhang, X.Z. Zhang, H.W. Zhao, Y.H. Zhu
    IMP, Lanzhou, People's Republic of China
  • W. Lu
    Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China
  
  Measurement of Bremsstrahlung radiation from ECR plasma can yield certain information of the ECR heating process and a plausible estimate of the X-ray heat load to the cryostat of a superconducting ECR source which needs seriously addressed. With a newly-developed collimation system, which defines a narrower spatial range of the measurement and provides an effective shielding from the background, a systematic measurement of the Bremmstrahlung emitted axially from the SECRAL (Superconducting ECR Ion Source with Advanced design in Lanzhou) plasma were carried out recently. The spectral temperature Tspe, a relative index of mean energy of the plasma hot electrons, was derived through linear fitting of the spectra in semi-logarithm coordinates. This article will present and discuss the evolutions of the X-ray flux and the hot electron energy with various source parameters, such as heating frequency, RF power and magnetic field configuration. And possible solutions to reduce the X-ray heat load induced by Bremsstrahlung radiation are proposed and discussed.  
poster icon Poster TUPOT009 [1.581 MB]  
 
TUPOT010 Effects of Microwave Frequency Fine Tuning on the Performance of JYFL 14 GHz ECRIS ion, ion-source, emittance, ECRIS 137
 
  • V.A. Toivanen, V.P. Aho, J. Ärje, P. Jones, J.A. Kauppinen, H. A. Koivisto, P. Peura, O.A. Tarvainen
    JYFL, Jyväskylä, Finland
  • L. Celona, G. Ciavola, S. Gammino
    INFN/LNS, Catania, Italy
  • A. Galatà
    INFN/LNL, Legnaro (PD), Italy
  • D. Mascali
    CSFNSM, Catania, Italy
  • T. Ropponen
    NSCL, East Lansing, Michigan, USA
  
  Measurements have been carried out at Department of Physics, University of Jyväskylä (JYFL) to study the effects of microwave frequency fine tuning on the performance of JYFL 14 GHz electron cyclotron resonance ion source. The frequency was varied within an 85 MHz band around the normal operation frequency of 14.085 GHz. The radial bremsstrahlung emission was measured for plasma diagnostics purposes and mass separated ion beam currents extracted from the ion source were recorded at the same time. Also, beam quality studies were conducted by measuring the ion beam emittance and shape with and without enhanced space charge compensation. The obtained results are presented and possible origins of seen phenomena in measured quantities are discussed.  
poster icon Poster TUPOT010 [0.678 MB]  
 
TUPOT011 Measurement of the Diamagnetic Current on the LBNL 6.4 GHz ECR Ion Source ECR, ECRIS, electron, ion-source 140
 
  • J.D. Noland, J.Y. Benitez, M. Kireeff Covo, D. Leitner, C.M. Lyneis
    LBNL, Berkeley, California, USA
  • O.A. Tarvainen
    JYFL, Jyväskylä, Finland
  • J. Verboncoeur
    UCB, Berkeley, California, USA
  
  Two standard plasma diagnostics (x-ray spectroscopy and measurement of the diamagnetic current) have been employed at the LBNL 6.4 GHz ECR. These diagnostics are combined with time resolved current measurements to study the plasma breakdown, build up and decay times, as well as electron heating. Individual charged particles in a magnetized plasma orbit in such a way that the magnetic field produced by their motion opposes any externally applied magnetic field. When a charged particle density gradient exists in a plasma, a net current arises. This “diamagnetic” current is proportional to the time-rate-of-change of the perpendicular component of the plasma pressure, and can be measured with a loop of wire as the plasma ignites or decays. Another common plasma diagnostic that is used to characterize an ECR plasma is measurement of the x-ray spectra created when energetic electrons scatter off of plasma ions. The x-ray spectra provide insight on the relative abundance of electrons of different energies, and thus the electron energy distribution function. The x-ray spectra can also be used to estimate the total x-ray power produced by the plasma. In this paper diamagnetic loop diagnostics and set-up is described in detail. In addition, diamagnetic loop and low energy x-ray measurements (few keV to 100 keV) taken on the LBNL 6.4 GHz ECR ion source are presented and discussed.  
poster icon Poster TUPOT011 [1.522 MB]  
 
TUPOT012 Microwave Frequency Dependence of the Properties of the Ion Beam Extracted From a Caprice Type ECRIS ion, ECRIS, ECR, ion-source 143
 
  • F. Maimone, R. Lang, J. Mäder, J. Roßbach, P. Spädtke, K. Tinschert
    GSI, Darmstadt, Germany
  • L. Celona
    INFN/LNS, Catania, Italy
  • F. Maimone
    DMFCI, Catania, Italy
  
  In order to improve the quality of ion beams extracted from ECR ion sources it is mandatory to better understand the relations between the plasma conditions and the beam properties. The present investigations concentrate on the analysis of different beam properties under the influence of various applications of frequency tuning and of multiple frequency heating. The microwave frequency feeding the plasma affects the electromagnetic field distribution and the dimension and position of the ECR surface inside the plasma chamber. This in turn has an influence on the generation of the extracted ion beam in terms of its intensity, of its shape and of its emittance. In order to analyze the corresponding effects measurements have been performed with the Caprice type ECRIS installed at the ECR Injector Setup (EIS) of GSI. The experimental setup uses a new arrangement of one or more microwave sweep generators which feed a Traveling Wave Tube amplifier covering a wide frequency range from 12.5 to 18 GHz. This arrangement provides a precise determination of the frequencies and of the reflection coefficient along with the beam properties. A sequence of viewing targets positioned inside the beam line monitors the beam shape.  
poster icon Poster TUPOT012 [1.245 MB]  
 
TUPOT013 Influence of Initial Plasma Density and Mean Electron Energy on the Preglow Effect simulation, electron, ion, ECR 146
 
  • I. Izotov, V. Sidorov, V. Skalyga, V. Zorin
    IAP/RAS, Nizhny Novgorod, Russia
  • H. A. Koivisto, O.A. Tarvainen, V.A. Toivanen
    JYFL, Jyväskylä, Finland
  
  The investigation of the Preglow effect is driven with the aim of creating a short-pulsed multicharged ion source. Recent experimental investigations have revealed strong influence of seed electrons, i.e. initial plasma density, on the amplitude and duration of the Preglow peak [1]. Present work, consisting of experiments and simulations, is dedicated to further investigation of the Preglow dependence on initial plasma density and electrons energy. Experimental investigation was performed at University of Jyväskylä (JYFL) with the A-ECR type ECRIS operated with 14 GHz frequency. Helium was used for the study. An initial ionization degree of the gas was varied by changing the pulse duration and duty factor. Time-resolved ion currents of He+ and He2+ were recorded. Calculations were made by using 0-dimensional model described in references [2], [3] and based on the balance equations for the particles confined in the magnetic trap. Results of simulation are compared with experimental Preglow peaks and discussed. Good agreement between experimental data and simulation encourages us to conduct a further study, aimed at optimizing the Preglow by tuning source parameters and initial plasma conditions.
[1] O. Tarvainen et al, Rev. Sci. Instrum., 81, 02A303, 2010.
[2] T. Thuillier et al, Rev. Sci. Instrum., 79, 02A314, 2008.
[3] I. Izotov et all. IEEE Trans. Plasma Sci. 36, 1494, 2008. 		 
poster icon Poster TUPOT013 [0.569 MB]  
 
TUPOT014 Optimized Extraction Conditions From High Power ECRIS by Dedicated Dielectric Structures ion, extraction, electron, ECRIS 147
 
  • L. Schächter, S. Dobrescu
    IFIN, Magurele- Bucuresti, Romania
  • K.E. Stiebing
    IKF, Frankfurt-am-Main, Germany
  
  The MD-method of enhancing the ion output from ECR ion sources is well established and basically works via two mechanisms, the regenerative injection of cold electrons from an emissive dielectric layer on the plasma chamber walls and via the cutting of compensating wall currents, which results in an improved ion extraction from the plasma. As this extraction from the plasma becomes a more and more challenging issue for modern ECRIS installations with high microwave power input, a series of experiments was carried out at the 14 GHz ECRIS of the Institut für Kernphysik in Frankfurt/Main, Germany (IKF). In contrast to our earlier work, in these experiments emphasis was put on the second of the above mechanisms namely to influence the sheath potential at the extraction by structures with special dielectric properties. Two different types of dielectric structures, Tantalum-oxide and Aluminum oxide (the latter also being used for the MD-method) with contrastingly different electrical properties were mounted on the extraction electrode of the IKF-ECRIS, facing the plasma. For both structures an increase of the extracted ion beam currents for middle and high charge states by 60-80 % was observed. The method is able to be applied also to other ECR ion sources for increasing the extracted ion beam performances.  
poster icon Poster TUPOT014 [0.510 MB]  
 
TUPOT015 Permanent Magnet ECRIS for the KEK Digital Accelerator ion, ECRIS, high-voltage, ion-source 150
 
  • K.W. Leo, T. Adachi
    Sokendai, Ibaraki, Japan
  • T. Arai, K. Koyama, M. Wake
    KEK, Ibaraki, Japan
  • K. Okazaki
    Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
  • K. Takayama
    TIT, Yokohama, Japan
  
  The existing KEK 500 MeV booster synchrotron is renovated into a digital accelerator (DA) capable of accelerating all species of ion [1]. The KEK-DA is an induction synchrotron employing no large injector. Its concept was demonstrated in 2006 using the 12 GeV proton synchrotron [2,3], where a proton bunch was accelerated with pulse voltages generated by a transformer instead of RF. In the KEK-DA, O, Ne, and Ar ions from the ECRIS embedded in the 200 kV high-voltage terminal (HVT) are directly injected into the ring though the low energy beam transport line. The permanent magnet ECRIS, in which a plasma is fired by x-band microwave pulses of 3 msec at 10 Hz, has been assembled at KEK. Its operational performance such as charge-state spectrum, emittance, and current is tested since the last year. In addition, the HVT with a voltage stabilizing circuit is being assembled now. Beam dynamical analysis from the cathode hall to the separation magnet, where possible charge-state ions are contaminated in the space-charge limit and beam focusing is realized through the Einzel lens and tandem acceleration gaps, is discussed as well as operational characteristics of the ECRIS.
[1] K. Takayama et al., “All-ion Accelerator: an Injector-free Synchrotron”, J. of Appl. Phys. 101, 063304(2007).
[2] K. Takayama et al., “Experimental Demonstration of the Induction Synchrotron”, Phys. Rev. Lett. 98, 054801 (2007).
[3] K. Takayama and R.Briggs (Eds.), Induction Accelerators (Springer-Verlarg, 2010). 		 
poster icon Poster TUPOT015 [1.947 MB]  
 
TUPOT017 CEA/Saclay Light Ion Sources Status and Developments ion, ion-source, extraction, emittance 156
 
  • R. Gobin, C.M. Mateo, S. Nyckees
    CEA/IRFU, Gif-sur-Yvette, France
  • G. Adroit, G. Bourdelle, N. Chauvin, O. Delferrière, Y. Gauthier, P. Girardot, F. Harrault, C. Marolles, B. Pottin, Y. Sauce, F. Senée, O. Tuske, T.V. Vacher, C. Van Hille
    CEA/DSM/IRFU, France
  
  After several years of high intensity light ion beam production with the SILHI source, CEA Saclay is now involved in the construction of different injectors dedicated to large infrastructures like IFMIF or Spiral 2. Other installations are also interested by high intensity ion sources like ESS or FAIR. Such machines plan to produce and accelerate proton or deuteron beams in pulsed or continuous mode. The SILHI source, based on ECR plasma generation, already demonstrated its performance in both modes. As a consequence, at present time the construction of 2 new injectors for Spiral 2 and IFMIF (source and low energy beam lines) is in progress at CEA/Saclay. This article will report on the status of both installations. It will also point out on additional developments presently under progress for high intensity beam characterization or plasma production understanding. Such developments are mainly done with the new BETSI test bench operating for several months.  
poster icon Poster TUPOT017 [2.020 MB]  
 
TUPOT018 Sheath Formation of a Plasma Containing Multiply Charged Ions, Cold and Hot Electrons, and Emitted Electrons electron, ion, resonance, ion-source 159
 
  • H.J. You
    NFRI, Daejon, Republic of Korea
  
  A model of sheath formation was extended to a plasma containing multiply charged ions (MCIs), cold and hot electrons, and secondary electrons emitted either by MCIs or hot electrons. The present study was motivated by the fact that the secondary electron yields are strongly dependent on the charge state of the ions and on the incident energy of electrons. Therefore, the contributions of the secondary electron emissions on the sheath formation would be severe in ECRIS plasmas where the charge state of ions is high and highly energetic electrons exist. In the model, modification of the “Bohm criterion” was given; thereby the sheath potential drop and the critical emission condition were analyzed. The model calculations were made mainly on the effects of the emitted electrons on the variations of the sheath potential drop, the particle and heat flux to the wall, by which some explanations for the effect of secondary electrons in ECR ion sources are given.  
poster icon Poster TUPOT018 [0.259 MB]  
 
WECOAK01 Characterization of the Microwave Coupling to the Plasma Chamber of the LBL ECR Ion Source. cavity, coupling, ECR, ion 162
 
  • C.M. Lyneis, J.Y. Benitez, D. Leitner, J.D. Noland, M.M. Strohmeier
    LBNL, Berkeley, California, USA
  • H. A. Koivisto, O.A. Tarvainen
    JYFL, Jyväskylä, Finland
  
  The characteristics of the microwave coupling of the 6.4 GHz ECR ion source were measured as a function of frequency, input power and time dependence. In addition the plasma diamagnetism and bremsstrahlung could be measured to help quantify the time dependence of the plasma build up and energy content. The LBL ECR plasma chamber, which has a diameter to wavelength ratio of 1.9 is not as over-moded as the 14 GHz AECR-U, which has a ratio greater than 3. This makes it possible to locate frequencies, where a single RF mode is predominately excited. For one of these modes we were able to demonstrate that with no plasma in the cavity, it is over-coupled and as the power is increased, the plasma density rises and the plasma loading increases it becomes under-coupled. By measuring the ratio of the incident to reflected power it is possible to show the microwave electric field levels saturate with increasing power. In the paper, the time dependence of the plasma loading and plasma diamagnetism as a function of input power and time are analyzed. The measurements of the plasma loading also provide insight into the dynamics of microwave heating in a multimode cavity.  
slides icon Slides WECOAK01 [1.593 MB]  
 
WECOAK02 Some Considerations About Frequency Tuning Effect in ECRIS Plasmas ion, electron, simulation, resonance 165
 
  • D. Mascali, G. Castro, L. Celona, G. Ciavola, N. Gambino, S. Gammino, R. Miracoli, L. Neri
    INFN/LNS, Catania, Italy
  • F. Maimone
    GSI, Darmstadt, Germany
  
  During the last years many experiments have demonstrated that slight variations in microwave frequency used to heat and sustain the plasma of ECRIS may strongly influence their performances (frequency tuning effect) both in terms of extracted current and mean charge state. Theoretical investigations revealed that this phenomenon can be correctly explained assuming that the plasma chamber works as a resonant cavity: standing waves are excited inside of it, and their spatial structure considerably changes even with slight variations of the pumping frequency. Therefore some particular modes present a higher electric field on the resonance surface, that is the only region in which the energy transfer from waves to electrons occurs. Experimental measurements carried out on microwave discharge plasmas at high density (up to 1011 cm-3) featured that even if the absorption of electromagnetic energy at the ECR surface is evident, the stochastic nature of the wave-electron interaction allows the wave to be reflected at the extraction flange, thus forming a standing wave. The model here proposed, and based on PIC and MonteCarlo collisional simulations, puts in evidence that the frequency tuning effect in ECRIS has a global influence on plasma properties: it strongly affects both ion and electron dynamics. Electron heating, electron density distribution, ion formation and acceleration at resonance surface, beam formation are determined by the particular mode excited inside the cavity. This means that the frequency tuning will be an important tool for future ECRIS for the optimization of the beam quality (emittance, etc.).  
slides icon Slides WECOAK02 [4.765 MB]  
 
WECOAK03 Studies of the ECR Plasma in the Visible Light Range ECR, ion, ECRIS, electron 168
 
  • S. Biri, R. Rácz
    ATOMKI, Debrecen, Hungary
  • J. Pálinkás
    DU, Debrecen, Hungary
  
  In order to investigate experimentally ECR plasmas one way is to record their optical spectra or photos in the infra-red, visible light (VL), ultra-violet or X-ray regions. The measurements and analysis of photos and spectra taken in any of these regions are usually affordable tasks. The non-destroying nature of this method is certainly an advantage, but the drawback is that the recorded information in most cases means integration over a specific line-of-sight in the plasma volume. Recently high resolution VL plasma photographs were taken at the ATOMKI-ECRIS using an 8 megapixel digital camera. Plasmas were generated from eight gases (He, methane, N, O, Ne, Ar, Kr, Xe) and from their mixtures. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas [1, 2]. It is a further challenging task to understand the colors of this special type of plasmas. The colors can be determined by the VL electron transitions of the plasma atoms and ions. Through the examples of He and Xe we analyze the physical processes which effects the characteristic colors of these plasmas.
[1] Rácz R., Biri S., Pálinkás J.: Electron cyclotron resonance plasma photos. Rev. Sci. Instrum. 81 (2010) 02B708.
[2] Rácz R., Biri S., Pálinkás J.: ECR Plasma Photographs as Plasma Diagnostic. Submitted to Plasma Sources Science and Technology. 		 
slides icon Slides WECOAK03 [1.573 MB]  
 
WECOAK04 Bremsstrahlung and Ion Beam Current Measurements With SuSI ECR Ion Source radiation, collimation, ion, extraction 171
 
  • T. Ropponen, D.G. Cole, G. Machicoane, A. Stolz, L.T. Sun, L. Tobos
    NSCL, East Lansing, Michigan, USA
  
  The Superconducting Source for Ions (SuSI) at the National Superconducting Cyclotron Laboratory at Michigan State University is a fully superconducting 3rd generation ECR ion source. The axial magnetic field is generated by six solenoid magnets which allow to control the magnetic field characteristics, such as resonance locations, mirror ratios and magnetic field gradients, almost independently. In addition, a collimation scheme in the SuSI beam line after the analyzing magnet has been developed to optimize the ion beam production from the ion source within a given acceptance. These aspects make SuSI an excellent tool for ECRIS research and development. In this paper we will focus on the bremsstrahlung and ion beam current measurements where the gradient on the magnetic field is changed while keeping the Bmin and axial plasma length as constants. We will also show how the shift of the extraction side resonance location affects the extracted ion beam currents and radiation spectra and, finally, we will discuss about the effect of flatB mode with a modern superconducting ECR ion source on the ion beam production and radiation levels.  
slides icon Slides WECOAK04 [3.752 MB]  
 
WECOAK05 Maximum Bremsstrahlung Energy Versus Different Heating Limits resonance, electron, ECRIS, photon 175
 
  • H. A. Koivisto, V.P. Aho, P. Jones, P. Peura, J.H. Sarén, O.A. Tarvainen, V.A. Toivanen
    JYFL, Jyväskylä, Finland
  
  A comprehensive set of bremsstrahlung measurements have been performed at JYFL (University of Jyväskylä, Department of Physics) in order to understand the parameters affecting the time evolution of electron energy. In order to extend the understanding of electron heating, a new set of measurements with the JYFL 6.4 GHz ECRIS have been initiated to further study the parameters affecting the maximum bremsstrahlung energy. In the measurements the effect of magnetic field gradient, microwave power, plasma size and gas pressure were studied. In the analysis, main focus will be given to compare the results with different theoretical electron heating limits.  
slides icon Slides WECOAK05 [0.739 MB]  
 
WECOBK02 Recent Performance of the ANL ECR Charge Breeder injection, ion, ECR, extraction 181
 
  • R.C. Vondrasek, A. Kolomiets, R.C. Pardo, R.H. Scott
    ANL, Argonne, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The construction of the Californium Rare Ion Breeder Upgrade (CARIBU), a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS), is nearing completion. The facility will use fission fragments, with charge 1+ or 2+, from a 1 Ci 252Cf source; thermalized and collected into a low-energy particle beam by a helium gas catcher. An existing ATLAS ECR ion source was modified to function as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. A surface ionization source or an RF discharge source provide beams for charge breeding studies. An achieved efficiency of 11.9% for 85Rb19+, with a breeding time of 200 msec, and 15.6% for 84Kr17+ has been realized. Both results are with the source operating with two RF frequencies (10.44 + 11.90 GHz). After modification to the injection side iron plug, the charge breeder has been operated at 50 kV, a necessary condition for the resolution of the isobar separator. 		 
slides icon Slides WECOBK02 [3.351 MB]  
 
WECOBK03 Fine Frequency Tuning of the PHOENIX Charge Breeder Used as a Probe for ECRIS Plasmas ion, injection, ECR, ion-source 184
 
  • T. Lamy, J. Angot, M. Marie-Jeanne, J. Médard, P. Sortais, T. Thuillier
    LPSC, Grenoble Cedex, France
  • A. Galatà
    INFN/LNL, Legnaro (PD), Italy
  • H. A. Koivisto, O.A. Tarvainen
    JYFL, Jyväskylä, Finland
  
  Fine frequency tuning of ECR ion sources is a main issue to optimize the production of multiply charged ion beams. The PHOENIX charge breeder operation has been tested in the range 13,75 - 14,5 GHz with an HF power of about 400 W. The effect of this tuning is analyzed by measuring the multi-ionization efficiency obtained for various characterized injected 1+ ion beams (produced by the 2.45 GHz COMIC source). The 1+/n+ method includes the capture and the multi ionization processes of the 1+ beam and may be considered as a plasma probe. The n+ spectra obtained could be considered, in first approach, as an image of the plasma of the charge breeder. However, in certain conditions it has been observed that the injection of a few hundreds of nA of 1+ ions (i.e.: Xe1+) in the plasma of the charge breeder, is able to destroy the charge state distribution of the support gas (i.e.: up to 40 % of O6+ and O7+ disappears). The study of this phenomenon will be presented along with plasma potential measurements for various charge states. This study may help to understand the ECRIS creation (or destruction) of highly charged ions.  
slides icon Slides WECOBK03 [7.745 MB]  
 
THCOAK01 A Correction Scheme for the Hexapolar Error of an Ion Beam Extracted from an ECRIS ion, simulation, extraction, emittance 191
 
  • P. Spädtke, R. Lang, J. Mäder, F. Maimone, J. Roßbach, K. Tinschert
    GSI, Darmstadt, Germany
  
  The extraction of any ion beam from ECRIS is determined by the good confinement of such ion sources. It has been shown earlier, that the ions are coming from these places, where the confinement is weakest. The assumption that the low energy ions are strongly bound to the magnetic field lines require furthermore, that only these ions which start on a magnetic field line which go through the extraction aperture can be extracted. Depending on the setting of the magnetic field, these field lines may come from the loss lines at plasma chamber radius. Because the longitudinal position of these field lines depends on the azimuthal position at the extraction electrode, the ions are extracted from different magnetic flux densities. Whereas the solenoidal component is not curable, the hexapolar component can be compensated by an additional hexapole after the first beam line focusing solenoid. The hexapole has to be rotatable in azimuthal direction and moveable in longitudinal direction. For a good correction the beam needs to have such a radial phase space distribution, that the force given by this hexapole act on the aberrated beam exactly in such a way to create a linear distribution after that corrector.  
slides icon Slides THCOAK01 [1.115 MB]  
 
THCOBK01 Concluding Remarks ion, ion-source, ECR, ECRIS 201
 
  • T. Nakagawa
    RIKEN Nishina Center, Wako, Japan
  
  Concluding remarks kindly done by Takahide Nakagawa  
slides icon Slides THCOBK01 [0.436 MB]