ECRIS2012 - List of Keywords (plasma)

Paper	Title	Other Keywords	Page
TUXO01	Coupling Microwave Power into ECR Ion Source Plasmas at Frequencies above 20 GHz	ECR, ion, ion-source, coupling	1
	C.M. Lyneis, J.Y. Benitez, M.M. Strohmeier, D.S. Todd LBNL, Berkeley, California, USA
	Electron Cyclotron Resonance (ECR) ion sources have been built to operate at frequencies from 5 GHz to 28 GHz and typically use a plasma chamber that serves as a multi-mode cavity. For small sources operating at 6 to 14 GHz cavity mode-like behavior has been reported. In these cavities the vacuum mode density is low enough that it may be that the RF power distribution can be understood in terms of excitation of a few modes. The large superconducting ECR ion sources, such as VENUS, operating at higher frequencies have a much greater mode density and very strong damping from plasma microwave adsorption. In this type of source, how the RF is launched into the plasma chamber will strongly affect the microwave coupling and the chamber walls will be less important. The VENUS source uses round over-moded TE01 mode waveguide to couple to the plasma, while most modern fusion devices use quasi-gaussian HE11 waves for injection into plasmas. In this paper we will describe the potential advantages of applying this technology to superconducting ECR ion sources as well as designs for doing so with VENUS.
	Slides TUXO01 [18.302 MB]

TUXO02	An Experimental Study of ECRIS Plasma Stability and Oscillation of Beam Current	ECR, ion, ion-source, ECRIS	5
	O.A. Tarvainen, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, V. Toivanen JYFL, Jyväskylä, Finland C.M. Lyneis, M.M. Strohmeier LBNL, Berkeley, California, USA
	The stability of oxygen ion beams extracted from ECR ion sources has been studied with the superconducting ion source VENUS at LBNL and with the A-ECR type 14 GHz ECRIS at JYFL. Discrete Fourier transform has been used for characterizing beam current oscillations in kHz range exhibited by both ion sources. The effect of source parameters on the frequency and amplitude of the oscillations is discussed. It was found that double frequency heating affects the oscillation frequency, biased disc can be used to mitigate the amplitude of beam current fluctuations, increasing B-minimum results to pronounced instabilities and operating the ion source with significantly higher mirror ratio than suggested by ECRIS scaling laws yields the most stable ion beams. It is argued that the observed beam current fluctuations are correlated with plasma instabilities. A 'roadmap' for identifying the plasma instability mechanisms responsible for beam current fluctuations is presented.
	Slides TUXO02 [2.195 MB]

TUXO03	Two-frequency Heating Technique for Stable ECR Plasma	ion, ECR, ion-source, ECRIS	10
	A. Kitagawa, M. Muramatsu NIRS, Chiba-shi, Japan S. Biri, R. Rácz ATOMKI, Debrecen, Hungary T.F. Fujita National Institute of Radiological Sciences, Chiba, Japan Y. Kato Osaka University, Graduate School of Engineering, Osaka, Japan N. Sasaki, W. Takasugi AEC, Chiba, Japan
	As a method to improve highly charged ion production, a technique to feed multiple microwaves with different frequencies is well-known. However the reason is not made sufficiently clear. Our group studied with two frequencies close together with a power of 600 W over by 18 GHz NIRS-HEC ECR ion source installed in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). As a result, it was revealed that the improvement of output beam current depends on the total power. In this case it seems that the two-frequency heating technique carries the advantage that the plasma instability at high microwave power is relieved. The effectiveness of an additional microwave depends on its frequency. It is necessary to optimize an additional frequency precisely; several tens MHz step against 18 GHz. The optimized frequency is directly influenced by the magnetic configuration. The necessary requirements for an additional microwave and the procedure of optimization in order to obtain a large advantage will be discussed.
	Slides TUXO03 [1.590 MB]

TUYO01	Experimental Study of Temperature and Density Evolution During Breakdown in a 2.45 GHz ECR Plasma	coupling, diagnostics, electron, ion	13
	O.D. Cortázar, A. Megía-Macías, A. Vizcaíno-de-Julián ESS Bilbao, LEIOA, Spain
	An experimental study of temperature and density evolution during breakdown in off-resonance ECR hydrogen plasma by time resolved Langmuir probe diagnostic is presented. Under square 2.45 GHz microwave excitation pulses with a frequency of 50 Hz and relative high microwave power, unexpected transient temperature peaks that reach 18 eV during 20 μs are reported at very beginning of plasma breakdown. Decays of such peaks reach final stable temperatures of 5 eV at flat top microwave excitation pulse. Evidence of interplay between incoming power and duty cycle giving different kind of plasma parameters evolutions engaged to microwave coupling times is observed. Under relative high power conditions where short microwave coupling times are recorded, high temperature peaks are measured. However, for lower incoming powers and longer coupling times, temperature evolves gradually to a higher final temperature without peaking. On the other hand, the early instant where temperature peaks are observed also suggest a possible connection with preglow and superadiabatic processes during breakdown in ECR plasmas.
	Slides TUYO01 [6.674 MB]

TUYO02	Control of the Plasma Transversal Losses, Caused by MHD Instabilities, in Open Mirror Magnetic Trap of the ECRIS: Recent Experiments on SMIS 37 Setup	ion, ECR, ion-source, electron	18
	V. Sidorov, I. Izotov, S. Razin, V. Skalyga, V. Zorin IAP/RAS, Nizhny Novgorod, Russia
	Funding: This work was partially performed in the framework of the Federal Targeted Program 'Scientific and Educational Personnel of the Innovative Russia' for 2009-2013 This work is a continuation of the experiments described in [1, 2] and aimed at the investigation of the new conceptions of MHD stabilization of plasma in open axisymmetric traps, specifically, it is aimed at the investigation of the shear flow influence on the transport control in open mirror traps. As in previous experiments, shear flow was created by limiter-electrode with bias potential according to the vacuum chamber. Plasma density structure in radial and azimuthal directions was studied. Mode structure of the perturbations was investigated. Substantial sharp shift of the plasma density maximum to the system axis with bias potential growth was demonstrated. It was shown, that the value of the bias potential that corresponds to the plasma density profile shift grows with the magnetic field growth that can be interpreted as the electron temperature growth. Some theoretical estimations of the influence of the transversal losses decrease on plasma parameters were made. [1] A.Sidorov, P.Bagryansky, A.Beklemishev et al. Trans. Fusion Sci. and Technology, 59, 112, (2011). [2] I.Izotov, S.Razin, A.Sidorov et al. Rev. Sci. Instrum., 83, 02A318 (2012).
	Slides TUYO02 [1.542 MB]

TUYO03	Secondary-electron-enhanced Plasma as an Alternative to Double/Variable-frequency Heating in ECRIS	ECRIS, ion, electron, experiment	22
	K.E. Stiebing IKF, Frankfurt-am-Main, Germany S. Dobrescu, L. Schächter IFIN, Magurele- Bucuresti, Romania
	As "double frequency heating" (DFH) now has become the method of choice to optimize the output from the newest generation ECRIS, it was a challenge to compare this method with the comparatively cheap method of "metal dielectric" (MD) structures introduced into the plasma chamber, which has also proven to strongly enrich the plasma with electrons that are effectively trapped and heated. Two RF-systems have been launched to the 14 GHz ECRIS, however, not allowing RF-differences as large as 1.5 GHz as demanded for DFH. Therefore the source was operated in a "frequency tuning" mode (FT) by optimizing the frequency difference by the output of Ar¹⁴⁺ ions. The data without and with MD-configuration are compared and related to data for the DFH. On the basis of Bremsstrahlung radiation spectroscopy and charge state analysis, it turned out that the FT-mode does not change the source performance substantially. The measured effects are in the order of 20% to 30% as reported elsewhere. In contrast to this, the enhancement gained by the MD method is much higher. The measured enhancement ratios even surpass those reported for real double frequency heating.
	Slides TUYO03 [5.642 MB]

TUYO04	Neutral Gas Temperature Measurements of a Radio Frequency Micro-thruster	ion, electron, background, vacuum	25
	A.D. Greig, R.W. Boswell, C. Charles, R.P. Hawkins SP3, Canberra, Australia M.D. Bowden, Y.C. Sutton The Open University, Milton Keynes, United Kingdom
	A radio frequency (13.56 MHz) capacitively coupled cylindrical argon plasma discharge was analysed using optical emission spectroscopy (OES) for various powers and pressures in the ranges 10 W to 40 W and 0.5 Torr to 5 Torr. Trace amounts of nitrogen were added to the discharge to estimate the temperature of the neutrals using rovibrational band matching of the 2^nd positive system of nitrogen and the 1^st negative system of nitrogen ions. Comparing simulated computer generated spectra of these bands to experimentally measured spectra determined the rotational and vibrational temperatures of the nitrogen, from which the temperature of the neutrals was inferred by assuming the rotational temperature was the same as the neutral gas temperature.
	Slides TUYO04 [1.341 MB]

TUZO03	New Extraction Design for the JYFL 14 GHz ECRIS	extraction, simulation, ion, space-charge	34
	V. Toivanen, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, O.A. Tarvainen JYFL, Jyväskylä, Finland
	Funding: VT acknowledges the financial support of the Ehrnrooth foundation. A new extraction system has been designed and constructed for the JYFL 14 GHz ECRIS at the Department of Physics, University of Jyväskylä (JYFL). The goal of the new design is to improve the performance of the ion source and increase the transmission efficiency of the low energy beam transport and the accelerator. The new extraction system is designed to be able to handle higher beam currents, yield better beam quality and offer more tuning flexibility. The design was made with the aid of simulations performed with the IBSimu code. The suitability of the code for this task was verified by simulating the old extraction system and good agreement between simulations and measurements was achieved. The new extraction system has been constructed, installed and tested. The new design, simulations and the first measurement results will be presented.
	Slides TUZO03 [4.470 MB]

TUPP04	Design of a Compact ECR Ion Source for Various Ion Production	ion, extraction, ion-source, ECR	49
	M. Muramatsu, S. Hojo, Y. Iwata, K. Katagiri, A. Kitagawa, Y. Sakamoto, S. Sato NIRS, Chiba-shi, Japan A.G. Drentje KVI, Groningen, The Netherlands T.F. Fujita National Institute of Radiological Sciences, Chiba, Japan
	Compact ECR ion source with all permanent magnets, so called Kei2, was developed for high energy carbon ion therapy facility at National Institute of Radiological Sciences. Kei2 source was design for production of only carbon ion for medical treatment. A copy of Kei2, so called KeiGM is used for Gunma University. Kei series are optimized for carbon ion production. In order to produce various ion beams for research, we design a new compact ECR ion source, so called Kei3. Kei3 is designed based on previous Kei series. In addition, there are three important points: 1) Movable beam extraction system for various extraction current densities, 2) An evaporator and MIVOC method for production of ions from solid materials and metal, and 3) Biased disk method and double frequency heating method for heavier ions. Same permanent magnets and microwave system will be used for easy maintenance and the cost effectiveness. Design of the Kei3 source will be described in this paper.

TUPP05	Charge-breeding at the Texas A&M University Cyclotron Institute	ion, injection, ECRIS, cyclotron	51
	D.P. May Texas A&M University Cyclotron Institute, College Station, Texas, USA J.E. Ärje JYFL, Jyväskylä, Finland G. Tabacaru Texas A&M University, Cyclotron Institute, College Station, USA
	The Cyclotron Institute of Texas A&M University is currently involved in an upgrade that is intended to produce beams of radioactive ions suitable for injection into the K500 superconducting cyclotron. As an integral part of this upgrade an electron-cyclotron-resonance ion source (CB-ECRIS) has been specially constructed by Scientific Solutions of San Diego, California for charge-breeding. This CB-ECRIS operates at 14.5 GHz and incorporates a hexapole of the Halbach style. Since radial injection of microwave power is ruled out, this presents special problems for the axial injection of low-charge-state ions for charge-breeding. Efforts at charge-breeding with stable ions will be presented as well as plans for the injection of low-charge-state, radioactive ions from cyclotron-driven ion guides, one for light radioactive ions and one for heavy radioactive ions.

TUPP08	Design Report of the AISHA Ion Source for Hadron Therapy Facilities	ECR, ion, injection, hadrontherapy	54
	G. Ciavola, L. Andò, L. Celona, S. Gammino, D. Mascali INFN/LNS, Catania, Italy G. Ciavola CNAO Foundation, Milan, Italy D. Mascali CSFNSM, Catania, Italy
	Different facilities for hadrontherapy have been built or designed in the recent past and Italy is present in the field either with synchrotron-based and with cyclotron-based facilities. For both types of accelerators the availability of high brightness multiply charged ion beams is essential and R&D efforts in this subject are increasing. In particular at the CNAO, proton and carbon ion beams will be accelerated up to 400 AMeV by a synchrotron and the beam injection is guaranteed by two identical ECR sources of the SUPERNANOGAN family modified according to the specifications we set. Optimisation of beam emittance and intensity is of primary importance to obtain the necessary current in the RFQ-LINAC and future facilities may require much better performances in terms of beam brightness than the ones provided by such commercial ECRIS. A hadron therapy center is going to be built in Catania and the R&D related to the injector has already started within the frame of a collaboration between the Regional Authority and INFN. The results of the research carried out at INFN-LNS will be presented along with the design of a relatively compact ECR ion source operating at 18 GHz, named AISHA.

TUPP13	Development of Intense Proton ECR Ion Sources at IMP	proton, ion, extraction, ECR	64
	Z.M. Zhang, Z.W. Liu, H.Y. Ma, L.T. Sun, Q. Wu, Y. Yang, W.H. Zhang, X.Z. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	Since 1997, there have been two ECR ion sources for producing intense proton beam developed at Institute of Modern Physics (IMP). In 1999, a high current 2.45 GHz ECR proton source for Lanzhou university neutron generator, was constructed and tested at IMP. A mixed ion (H¹⁺ + H²⁺ + H³⁺) beam current of 110 mA with CW mode was delivered from a single aperture of 6mm diameter with microwave power of 600 W at the extraction voltage of 22 kV. Recently a new pulsed proton source has been designed and built at IMP for the CPHS (Compact Pulse Hadron Source) facility in Tsinghua University. Now this source is under commissioning for 60 mA proton beam with 50 keV energy. The long time running stability and beam emittance have been tested and the results are well up to the requirements of CPHS. In this paper, after a short review of the proton ion source for Lanzhou University, the design and test results of the CPHS proton source as well as the LEBT will be presented. The design of the proton ion source and the LEBT for the Chinese ADS project will also be discussed in the contents.

WEXO02	Recent Developments and Electron Density Simulations at the ATOMKI 14.5 GHz ECRIS	electron, ion, simulation, ECRIS	77
	S. Biri, R. Rácz ATOMKI, Debrecen, Hungary J. Pálinkás University Debrecen, Debrecen, Hungary
	The 14.5 GHz ECR ion source of ATOMKI is a standard room-temperature ECRIS devoted for plasma diagnostic studies, for atomic physics research and also serves as a particle source with wide range of elements for surface treatments. From the beginning lots of technical modifications and developments have been carried out on the ion source. The changes aimed the increasing of the beams charge, intensity and the widening of the ion choice. Other modifications were done to develop special, non-standard operation modes or to produce peculiar plasmas or beams. Recently the original NdFeB hexapole was exchanged by a new one and new iron plugs were calculated, designed and installed at the injection side of the source. The resulted stronger magnetic trap has shown significant effect on the beam intensity and on the charge states distribution. The new magnetic configuration was re-calculated by the TrapCAD code developed by our group. The spatial movement and energy evolution of a high number of electrons were followed in the calculation. A post-calculation energy filtering carried out for the lost and non-lost electrons reveals numerous interesting and important information in 3D.
	Slides WEXO02 [11.678 MB]

WEXO03	Numerical Modeling of Ion Production in ECRIS by using the Particle-in-Cell Method	ion, extraction, ECR, ECRIS	82
	V. Mironov, J.P.M. Beijers KVI, Groningen, The Netherlands
	To better understand the physical processes in ECRIS plasmas, we developed a Particle-in-Cell code that follows the ionization and diffusion dynamics. The basic features of the numerical model are given elsewhere. An electron temperature of about 1 keV is needed to reproduce the experimentally observed performance of our 14 GHz ECR source. We assume that a pre-sheath is located outside the ECR zone, where the ion acceleration toward the walls occurs. Electric field inside the ECR zone is supposed to be zero. The ion production is modeled assuming the ion confinement by a ponderomotive barrier formed at the boundary of the ECR zone. The barrier height is defined by the RF radiation density at the electron resonance layer and is taken as an adjustable parameter; when the plasma becomes overdense, we set the barrier value to zero. With these assumptions, we are able to reproduce the main features of ECRIS performance, such as the saturation and decrease of highest charge state currents with increasing gas pressure, as well as response to an increase of injected RF power. Afterglow and frequency-tuning effects can be explained by introducing the ponderomotive barrier. V. Mironov and J. P. M. Beijers, "Three-dimensional simulations of ion dynamics in the plasma of an electron cyclotron resonance ion source", Phys. Rev. ST Accel. Beams 12, 073501 (2009).
	Slides WEXO03 [7.032 MB]

WEXO04	Proton Beams Formation from Dense Plasma of ECR Discharge sustained by 37.5 GHz Gyrotron Radiation	extraction, ion, proton, emittance	85
	V. Skalyga, I. Izotov, S. Razin, V. Sidorov, V. Zorin IAP/RAS, Nizhny Novgorod, Russia T. Kalvas, H. A. Koivisto, O.A. Tarvainen JYFL, Jyväskylä, Finland
	Funding: Work was performed in frame of realization of federal targeted program "Scientific and pedagogical labor force for an innovative Russia" for 2009-2013 yy. Operation of modern high power accelerators often requires production of intense beams of hydrogen ions. Newer facilities aiming at outperforming the previous generation accelerators are usually designed for higher beam currents. Meeting the demand for hydrogen ion beams with higher intensity and low transverse emittance is, therefore, becoming increasingly difficult problem. Present work is devoted to experimental investigation of proton beams production from dense plasma (Ne>10¹³ cm^-3) of ECR discharge sustained by 37.5 GHz, 100 kW gyrotron radiation at SMIS 37 facility at IAP RAS. Different extraction system configurations were used. It was demonstrated that ultra bright proton beam with 4.5 mA current and 0.1 π·mm·mrad normalized emittance (brightness=45 A/(π·mm·mrad)²) can be formed with 1-hole (1 mm in diameter) extraction. For production of high current beams a 13-hole extractor was used. 200 mA and 1.1 π·mm·mrad normalized emittance proton beam was obtained. A possibility of further beam parameters enhancement by developing of extraction system and its power supply is discussed. It was shown that in generated proton beams H²⁺ component was less than 6%.
	Slides WEXO04 [2.512 MB]

WEXO05	Effect of Source Tuning Parameters on the Plasma Potential of Heavy Ions and its Influence on the Longitudinal Optics of the High Current Injector	ion, rfq, electron, emittance	90
	G.O. Rodrigues, D. Kanjilal, P.S. Lakshmy, A. Mandal, Y. Mathur, A. Roy IUAC, New Delhi, India R. Baskaran IGCAR, Channai, India
	Plasma potentials for various heavy ions have been measured using the retarding field technique in the 18 GHz High Temperature Superconducting ECR ion source, PKDELIS. The influence of various source parameters viz., RF power, gas pressure, magnetic field, negative DC bias and gas mixing on the plasma potential is studied. It is observed that the plasma potentials are decreasing for increasing charge states and a mass effect is clearly observed for the ions with similar operating gas pressures. In the case of gas mixing, it is observed that the plasma potential minimises at an optimum value of the gas pressure of the mixing gas and the mean charge state maximises at this value. The energy spread arising from the plasma potential influences the longitudinal optics of the high current injector in terms of increased phase spread which deteriorates the transmission through the RFQ. Details of the measurements carried out as a function of various source parameters and its impact on the longitudinal optics are presented.
	Slides WEXO05 [11.394 MB]

WEYO02	Experimental Results: Charge-state and Current-density Distribution at the Plasma Electrode of an ECR Ion Source	ion, extraction, ion-source, ECR	101
	L. Panitzsch, T. Peleikis, M. Stalder, R.F. Wimmer-Schweingruber IEAP, Kiel, Germany
	We have measured the current-density in very close vicinity (15 mm downstream) of the plasma electrode of our hexapole-geometry electron-cyclotron-resonance ion source (ECRIS). For this, we equipped our 3D-movable puller electrode with a customized Faraday Cup (FC) inside. To achieve high spatial resolution we reduced the aperture of the puller electrode to only 0.5 mm. Thus, the source-region of the extracted ion beam is limited to a very small area of the plasma electrode's hole (d = 4 mm). The information about the charge-state distribution and the current density in the plane of the plasma electrode is conserved in the ion beam and was scanned by remotely moving the small-aperture puller electrode (incl. FC) across the aperture of the plasma electrode. From additional m/q- measurements for the different positions we can deduce that different ion charge-states are grouped into bloated triangles of different sizes but with the same orientation in the plane of the plasma electrode with the current density peaking at the centre. This confirms simulations by various groups as well as some emittance measurements, but adds spatial resolution for the different charge-states.
	Slides WEYO02 [2.298 MB]

WEYO03	Ion Beam Extraction from Magnetized Plasma	ion, electron, extraction, ion-source	106
	P. Spädtke, R. Lang, J. Mäder, F. Maimone, J. Roßbach, K. Tinschert GSI, Darmstadt, Germany
	With increasing the total extracted current for any ion source, the optimisation of the extraction system becomes more important, because of the space charge effect. Several attempts have been made in the past to simulate the extraction from an Electron Cyclotron Resonance Ion Source (ECRIS) in a correct way. Most of these attempts failed, because they were not able to reproduce the experimental results. The best model up to now is given by the following procedure: tracing the magnetic field lines through the extraction aperture, looking where these field lines are coming from; using these coordinates of the magnetic field line as starting points for ions to be extracted; the initial current of each trajectory is determined by theoretical assumptions about the plasma or by a plasma simulation; Child's law is applicable locally only in direction of the magnetic field, if no emission limited flow is present.
	Slides WEYO03 [16.955 MB]

WEZO01	Status of the SEISM Experiment	injection, extraction, resonance, ECR	111
	M. Marie-Jeanne, J. Angot, P. Balint, C. Fourel, J. Giraud, J. Jacob, T. Lamy, L. Latrasse, P. Sortais, T. Thuillier LPSC, Grenoble Cedex, France C. Daversin, F. Debray, C. Trophime, S. Veys GHMFL, Grenoble, France I. Izotov, V. Skalyga, V. Zorin IAP/RAS, Nizhny Novgorod, Russia
	Funding: This work has been supported by the EuroMagNET II under the EU contract number 228043 and by the European Commission Framework Programme 7 Design Study: EUROnu, Project Number 212372. LPSC and LNCMI (Laboratoire National des Champs Magnétiques Intenses) of Grenoble have developed the first and unique magnetic confinement structure in the world that allows a closed 60 GHz ECR zone, using high field magnet technologies. The magnetic structure has been validated for 28 GHz resonance and a closed 1 T iso-B surface was measured. Calculated and measured field maps were carefully compared in order to determine an operation range for 28 GHz plasma tests. A whole test bench, including high pressure water for helix cooling, intense currents (up to 15 kA) for helix powering and a beam line with mass separation is under construction at LNCMI. This contribution presents the status of the experiment, hopefully including the results of the first beam tests scheduled in September. The 350 kW - 60 GHz gyrotron has been built at IAP, the status of its operation will be shown.
	Slides WEZO01 [11.245 MB]

WEZO02	Design of new 18 GHz ECR for RIKEN RIBF	ion, ion-source, ECRIS, solenoid	114
	K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi RIKEN Nishina Center, Wako, Japan
	In RIKEN RIBF, we plan to install a new 18 GHz ECR ion source, which supply the intense beam of highly charged heavy ion beam into the linear accelerator RILAC. By equipping two ion sources, it is expected to be able to develop new beams while we produce the beam for the experiment of RIBF. Based on the structure of 18 GHz ECR ion source which have been developed in RIKEN, this ion source has additional features as follows: Owing to three solenoid coils, Bext can be adjusted while Bmin is fixed to an optimum value. We adopt the variable frequency (17.2-18.4 GHz) RF power source. Therefore, further enhancement of the beam intensity is expected because the frequency band suited to a size of plasma chamber is selectable, In order to simplify the maintenance work, we improved a structure of the chamber. In this contribution, we report the design of new ion source in detail.
	Slides WEZO02 [10.113 MB]

WEZO03	Recent Results of PHOENIX V2 and New Prospects with PHOENIX V3	ion, ECR, booster, operation	117
	T. Thuillier, J. Angot, T. Lamy, M. Marie-Jeanne LPSC, Grenoble Cedex, France C. Barue, C. Canet, M. Dupuis, P. Lehérissier, F. Lemagnen, L. Maunoury, O. Osmond GANIL, Caen, France C. Peaucelle IN2P3 IPNL, Villeurbanne, France P. Spädtke GSI, Darmstadt, Germany
	Funding: This work is partially funded by the European Commission under the 7th Framework Programme Grant Agreement 283745 (CRISP) The 18 GHz PHOENIX V2 ECRIS is running since 2010 on the heavy ions low energy beam transport line (LEBT) of SPIRAL2 installed at LPSC Grenoble. PHOENIX V2 will be the starting ion source of SPIRAL 2 at GANIL. The status and future developments of this source are presented in this paper. Recent studies with Oxygen and Argon beams at 60 kV have demonstrated reliable operation at 1.3 emA of O⁶⁺ and 200 eμA of Ar¹²⁺. Metallic ion beam production has been studied with the Large Capacity Oven developed by GANIL and 20 eμA of Ni¹⁹⁺ have been obtained. In order to improve further the beam intensities for Spiral2, an economical upgrade of the source named PHOENIX V3 has been recently decided by the project management. The goal is to double the plasma chamber volume from 0.6 to 1.2 liter by increasing the chamber wall radius, keeping the whole magnetic confinement intensity unchanged. The PHOENIX V3 magnetic design will be presented along with a status of the project.
	Slides WEZO03 [8.818 MB]

WEPP02	Relationship of Performance and RF Resonance Modes	ion, ECR, ion-source, resonance	121
	T. Hattori, A. Kitagawa, M. Muramatsu NIRS, Chiba-shi, Japan N. Hayashizaki RLNR, Tokyo, Japan
	The performance of Electron Cyclotron Resonance (ECR) ion source depends on the operation frequency, the magnetic mirror field, the maltipole field, the mirror ratio, the ECR zone and others. We studied the relationship of performance and operation frequency in ECR ion source (HiECR-3). The performance (beam intensity of Ar⁹⁺ ion) was measured according to change of frequency from 9.7 to 11.7 GHz in fixed magnetic field of HiECR ion source. We measured resonant frequencies of plasma chamber of HiECR ion source in condition of no plasma (current of mirror coils is zero). The data of intensity of Ar⁹⁺ related to measured resonant frequencies. Their resonant modes were checked with a 3D electromagnetic simulator (High Frequency Structure Simulator). As a result, it became clear that the performance of the ion source depends on electric-field distribution of the RF resonant mode.

WEPP03	Plasma Instability in the Afterglow of ECR Discharge Sustained in a Mirror Trap	electron, ion, ECR, detector	125
	I. Izotov, A. Mansfeld, V. Skalyga, V. Zorin IAP/RAS, Nizhny Novgorod, Russia T. Grahn, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, P. Peura, O.A. Tarvainen, V. Toivanen JYFL, Jyväskylä, Finland
	Funding: Work was performed in frame of realization of federal targeted program "Scientific and pedagogical labor force for an innovative Russia" for 2009-2013 yy. A number of studies have been devoted to the investigations of plasma decay in ECR heated discharges confined in a mirror magnetic trap. The motivation of this work is to study plasma instabilities causing perturbations of ion current during the plasma decay. Present work is devoted to time-resolved diagnostics of non-linear effects observed during the afterglow plasma decay of an 14 GHz Electron Cyclotron Resonance Ion Source (ECRIS) at JYFL operated in pulsed mode. Plasma instabilities causing perturbations of extracted ion current during the decay were observed and studied. It is shown that these perturbations are associated with precipitation of high energy electrons along the magnetic field lines and strong bursts of bremsstrahlung emission. The effect of ion source settings on the onset of the observed instabilities was investigated. Based on the experimental data and estimated plasma properties it is assumed that the instabilities are of cyclotron type. The conclusion is supported by a comparison to other type of plasma devices (SMIS 37, IAP RAS) exhibiting similar characteristics but operating in a different plasma confinement regime.

WEPP15	Metal Ion Beam Production with Improved Evaporation Ovens	ion, operation, ECRIS, ion-source	140
	K. Tinschert, R. Lang, J. Mäder, F. Maimone, J. Roßbach GSI, Darmstadt, Germany
	Most of the ion beams delivered by the ECR ion sources at the GSI accelerator facilities are produced from materials in the solid state, which must be transformed into the gaseous state to feed the plasma. The well established method of thermal evaporation has been used by means of two types of resistively heated ovens for metals and solid compounds. The main goal of development is to improve their versatility in terms of lifetime, durability, efficiency, and extended temperature range. Recent investigations and developments include the use of alternative materials for oven components. The main focus has been on the further development of the high temperature oven. A modular construction with improved mechanical dimensional accuracy for more precise and easier mounting has been established. Its optimization for stable long time operation has been continued leading to a lifetime of 6 days for evaporation of Ti at 1750°C. Furthermore the temperature limit could be extended to 2300°C. In addition to the improvements in evaporation technology the technique of microwave frequency tuning could be successfully applied for metal ion operation leading to enhanced ion beam intensities.

WEPP16	Experimental Studies on the ALISES Ion Source at CEA Saclay	ion, ion-source, electron, extraction	143
	O. Tuske, O. Delferrière, Y. Gauthier, R. Gobin, F. Harrault, J.L. Jannin CEA/DSM/IRFU, France S. Nyckees CEA/IRFU, Gif-sur-Yvette, France
	The ALISES ion source was originally designed to reduce beam emittance at RFQ entrance by shortened the length of the LEBT. A wide opened magnetic coil at ground potential produces the fringe field needed for the ECR heating at 2.45 GHz frequency. The first part describes the commissioning of the source: Penning discharges inside the accelerating column make the high voltage power supply collapse. Experimental tests with kapton films while discharges occur, and simulations with OPERA-3D code have shown great similarities to detect the location of those discharges and allow us to make the ion source work. The second part of this paper will present the result of low intensity light ion beam production versus the plasma chamber length and radius. Those very preliminary tests give us indications to reduce the ion source dimensions.
	Poster WEPP16 [2.556 MB]

WEPP17	A Multi-Sample Changer Coupled to an ECR Source for AMS Experiments	laser, ion, ECR, ion-source	146
	R.C. Vondrasek, T. Palchan, R.C. Pardo, C.E. Peters, M.A. Power, 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. A project using Accelerator Mass Spectrometry (AMS) at the ATLAS facility to measure neutron capture rates on a wide range of actinides in a reactor environment is underway. This project will require the measurement of a large number of samples previously irradiated in the Advanced Test Reactor at Idaho National Laboratory. The AMS technique at ATLAS is based on production of highly-charged positive ions in an electron cyclotron resonance ion source (ECRIS) followed by acceleration in the ATLAS linac. The sample material is introduced into the plasma via laser ablation. This should limit the dependency of material feed rates upon the source material composition as well as minimize cross-talk between samples. A new multi-sample changer has been constructed allowing rapid changes between samples. The sample changer has 20 positions and is capable of moving from one sample to the next in one minute. Details of the sample changer design and operation will be presented.

THXO01	Optimization of the New SC Magnetic Structure Design with a Hybrid Magnet	injection, solenoid, ECRIS, sextupole	149
	D. Xie, W. Lu, L.Z. Ma, L.T. Sun, X.Z. Zhang, H.W. Zhao, L. Zhu IMP, Lanzhou, People's Republic of China
	In the development of the next generation ECRISs, so far either a set of full NbTi or full Nb₃Sn magnets has been proposed to construct the magnet system. However, the single set of magnets may not be the optimum in terms of the field strength and configuration. An optimization of the new SC magnetic structure with a set of hybrid magnets (NbTi and Nb₃Sn) is being investigated. With the hybrid magnet the optimized new magnetic system is capable of producing field maxima of 9.0 T on axis and 4.0 T at the plasma wall, which are 30 and 10% higher than the previously proposed magnetic structure to be built with a set of full NbTi magnets. In addition, the axial length of the optimized magnetic structure has been slightly shrunk resulting in a more compact system. This new magnetic field profile is high enough for operation frequency up to 56 GHz. The design features and the preliminary force/stress analyses of the optimized new SC magnetic structure will be presented and discussed.
	Slides THXO01 [2.603 MB]

THXO02	Current Developments of the VENUS Ion Source in Research and Operations	ion, extraction, cyclotron, ion-source	153
	J.Y. Benitez, K.Y. Franzen, C.M. Lyneis, L. Phair, M.M. Strohmeier LBNL, Berkeley, California, USA G. Machicoane FRIB, East Lansing, Michigan, USA L.T. Sun IMP, Lanzhou, People's Republic of China
	The VENUS ion source functions as a research and development tool in the ECR community as well as an injector for LBNL's 88-Inch cyclotron. In order to meet the needs of both the ECR community and users at the 88-Inch cyclotron, technology such as ovens and a sputter probe have been developed for introducing metals into the plasma. Using a modified high temperature oven, VENUS has produced 450 eμA of ²³⁸U³³⁺ and 400 eμA of ²³⁸U³⁴⁺, twice the required Uranium beam current needed for FRIB. In addition, after upgrading its high voltage capabilities VENUS produced 11emA of ⁴He²⁺, a capability that remains unparalleled by other ECR ion sources. In addition to its recent record high intensities VENUS is also being developed to deliver low intensity, ultra high charge state ions for the cocktails beams, where many species are produced simultaneously for use by the BASE Facility. ¹²⁴Xe⁴³⁺ is now in regular production for the 16 MeV/u cocktail, and development of ²⁰⁹Bi⁵⁶⁺ for the 10 MeV/u cocktail is in progress and has been accelerated through the 88-Inch cyclotron. This paper presents the latest work towards integrating the VENUS ion source into our research and operational goals.
	Slides THXO02 [8.391 MB]

THYO01	Operation of an ECRIS Charge State Breeder at TRIUMF	ion, background, experiment, ECR	163
	F. Ames, R.A. Baartman, P.G. Bricault, K. Jayamanna, A. Mjøs TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	After initial commissioning of the charge state breeder for radioactive ions at the TRIUMF/ISAC facility further tests on the performance of the system have been performed. One of the major problems found was the high background of stable ions from the ECR source, mainly C, N, O, Ar, Fe, Ni, C and Cr. The main source of those is the residual gas and sputtered material from the plasma chamber wall and from the surrounding electrodes. Although their intensity is small it can be orders of magnitude more than the intensity from the radioactive ions. Therefore, the original stainless steel plasma chamber of the Pantechnik PHOENIX ECR source has been exchanged to aluminium with an ultra pure aluminium coating, all electrodes for injection and extraction of the ions have been replaced with aluminium and the iron joke at the extraction side, which is part of the vacuum system in the PHOENIX source has been coated as well. This combined effect has reduced the amount of background ions substantially. Detailed results on the performance of the source after those changes will be presented.
	Slides THYO01 [1.634 MB]

THYO02	LPSC PHOENIX ECR Charge Breeder Beam Optics and Efficiencies	extraction, ion, injection, emittance	167
	J. Angot, T. Lamy, M. Marie-Jeanne, P. Sortais, T. Thuillier LPSC, Grenoble Cedex, France
	The PHOENIX ECR charge breeder characteristics (efficiency and charge breeding time) were measured at CERN-ISOLDE and LPSC, they were considered as sufficient to allow its setup on various facilities (TRIUMF-Canada/GANIL-SPIRAL2-France/SPIRAL1). The developments performed at the Argonne National Laboratory (USA) have shown that the ECR charge breeder efficiencies could be much higher than the ones obtained with PHOENIX, without major differences between the two devices. We have tried to study the possible reasons of such different results in order to improve the PHOENIX charge breeder characteristics. The transmission value of the n+ beam line has been measured to be as low as 30%. Emittances of the total beam extracted from the source and of some analyzed beams (after the magnetic spectrometer) have been measured and will be presented. Simulations have shown a too low vertical acceptance at the center of the dipole. Simulations and experimental results will be presented to show how an additional Einzel lens inserted just before the dipole have drastically improve the beam transmission. The impact of this new beam transport on efficiency results will be presented.
	Slides THYO02 [4.337 MB]

THYO04	Performance of the ANL ECR Charge Breeder with Low Mass Beams	ion, injection, ECR, ion-source	177
	R.C. Vondrasek, S.V. Kutsaev, R.C. Pardo, R.H. Scott ANL, Argonne, USA P. Delahaye, L. Maunoury GANIL, Caen, France
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. The Californium Rare Ion Breeder Upgrade (CARIBU) of the ATLAS superconducting linac facility aims at providing low-energy and reaccelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. These beams are obtained from fission fragments of a Cf-252 source, thermalized and collected into a low-energy particle beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred with an ECR ion source for acceleration in ATLAS. The charge breeding program had focused on optimizing beams in the mid-mass range, achieving high charge breeding efficiencies of both gaseous and solid species including 14.7% for the radioactive species ¹⁴³Ba²⁷⁺. In an effort to better understand the charge breeding mechanism, we recently focused on the low-mass species sodium and potassium which up to present have been difficult to charge breed efficiently. Charge breeding efficiencies of 10.1% for ²³Na⁷⁺ and 17.9% for ³⁹K¹⁰⁺ were obtained injecting stable Na⁺ and K⁺ beams from a surface ionization source. Details of these studies will be presented as well as simulations detailing the injection of the low charge state beams into the charge breeder.
	Slides THYO04 [9.178 MB]

FRXA01	High Intensity Beam Production at CEA/Saclay for the IFMIF Project	rfq, extraction, emittance, solenoid	182
	R. Gobin, G. Adroit, D. Bogard, N. Chauvin, O. Delferrière, Y. Gauthier, P. Girardot, F. Harrault, J.L. Jannin, D. Loiseau, P. Mattei, A. Roger, F. Senée, O. Tuske CEA/DSM/IRFU, France
	At CEA/Saclay, IRFU institute is in charge of the design, construction and characterization of the 140 mA continuous deuteron Injector for the IFMIF project. This injector includes the source and the low energy beam line (LEBT) with its own diagnostics. The Electron Cyclotron Resonance (ECR) ion source operates at 2.45 GHz and the 2 m long LEBT is based on 2 solenoids. Krypton gas injection in the beam line is foreseen in order to reach a high level of space charge compensation for the beam matching at the RFQ entrance. During the last months hydrogen beam has been produced in pulsed and continuous mode and the beam diagnostics have been installed and commissioned. Recently a 125 mA-100 keV pulsed deuteron beam has been produced with a 1% duty cycle. In this article, the high intensity proton and deuteron beam characterization will be presented.
	Slides FRXA01 [9.797 MB]

FRXA02	All Permanent Magnet ECR Ion Source Development and Operation Status at IMP	ion, ion-source, ECR, permanent-magnet	185
	L.T. Sun, Y. Cao, J.Q. Li, J.Y. Li, B.H. Ma, H. Wang, J.W. Xia, D. Xie, W.H. Zhang, X.Z. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	All permanent magnet ECR ion sources have many advantages over traditional ECR ion sources composed of several axial room temperature solenoids and one permanent magnet hexapole magnet, which make them the first choice for many heavy ion facilities and platforms. At IMP, three types of all permanent magnet ECR ion sources have been built for different applications, i.e. the very compact ECR ion source LAPECR1 for intense mono or multi charge state ion beam production, the LAPECR2 ion source installed on the 320 kV high voltage multidisciplinary platform, and the LAPECR3 ion source dedicated to C⁵⁺ beam production for the cancer therapy facility. In this paper, after a general discussion of the ion sources' design, the applications and the operation status of the IMP all permanent magnet ECR ion sources will be presented.
	Slides FRXA02 [6.380 MB]

FRXA03	Laser Ablation of Actinides into an Electron Cyclotron Resonance Ion Sources for Accelerator Mass Spectroscopy	laser, ion, ECR, target	190
	T. Palchan, F.G. Kondev, S.A. Kondrashev, C. Nair, R.C. Pardo, R.H. Scott, R.C. Vondrasek ANL, Argonne, USA W. Bauder, P. Collon University of Notre Dame, Indiana, USA J.F. Berg, T. Maddock, G. Palmotti, M. Salvatores, G. Youinou INL, Idaho Falls, Idaho, USA G. Imel ISU, Pocatello, Idaho, USA M. Paul The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel M. Salvatores CEA Cadarache, Saint Paul Lez Durance, France
	Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357. A project using accelerator mass spectrometry (AMS) is underway at the ATLAS facility to measure the atom densities of transmutation products present in samples irradiated in the Advanced Test Reactor at INL. These atom densities will be used to infer effective actinide neutron capture cross-sections ranging from Thorium to Califorium isotopes in different neutron spectra relevant to advanced fuel cycles. This project will require the measurement of many samples with high precision and accuracy. The AMS technique at ATLAS is based on production of highly-charged positive ions in an ECRIS followed by injection into a linear accelerator. We use a picosecond laser to ablate the actinide material into the ion source. We expect that the laser ablation technique will have higher efficiency and lower chamber contamination than sputtering or oven evaporation thus reducing 'cross talk' between samples. The results of off-line ablation tests and first results of an accelerate beam generated by the laser coupled to the ECR will be discussed as well as the overall project schedule.
	Slides FRXA03 [11.825 MB]

FRYA03	ECRIS Related Research and Development Work at JYFL and Some Future Prospects	ion, ion-source, photon, electron	203
	H. A. Koivisto, J. Ärje, T. Kalvas, J.P.O. Komppula, R.J. Kronholm, J.P. Laulainen, O.A. Tarvainen, V. Toivanen JYFL, Jyväskylä, Finland
	Since the last ECR workshop the JYFL ion source group has focused on the plasma research, work on the ion beam formation and transport and development of metal ion beams. The plasma research can be divided into plasma breakdown processes, plasma and ion beam instabilities and afterglow processes. The afterglow and instability experiments will be presented elsewhere in these proceedings [1]. In addition, studies involving in the photoelectric induced electron emission and charge exchange reactions will be briefly discussed and the experiments concerning the resonance properties of empty and plasma loaded cavity will be presented. An improvement in ion beam transport of the JYFL K130 cyclotron facility was achieved as a result of the work performed on ion beam formation. This work will be described in more detailed elsewhere in these proceedings [2]. The MIVOC method and sputtering technique were further studied in order to produce intensive titanium ion beams. As a result, an intensive {50}Ti ion beam was successfully produced with the MIVOC method and interesting behavior regarding the sputtering was noticed. [1] V. Skalyga et al. and O. Tarvainen et al. [2] V. Toivanen et al.
	Slides FRYA03 [4.159 MB]

Paper

Title

Other Keywords

Page

TUXO01

Coupling Microwave Power into ECR Ion Source Plasmas at Frequencies above 20 GHz

ECR, ion, ion-source, coupling

1

C.M. Lyneis, J.Y. Benitez, M.M. Strohmeier, D.S. Todd
LBNL, Berkeley, California, USA

Electron Cyclotron Resonance (ECR) ion sources have been built to operate at frequencies from 5 GHz to 28 GHz and typically use a plasma chamber that serves as a multi-mode cavity. For small sources operating at 6 to 14 GHz cavity mode-like behavior has been reported. In these cavities the vacuum mode density is low enough that it may be that the RF power distribution can be understood in terms of excitation of a few modes. The large superconducting ECR ion sources, such as VENUS, operating at higher frequencies have a much greater mode density and very strong damping from plasma microwave adsorption. In this type of source, how the RF is launched into the plasma chamber will strongly affect the microwave coupling and the chamber walls will be less important. The VENUS source uses round over-moded TE01 mode waveguide to couple to the plasma, while most modern fusion devices use quasi-gaussian HE11 waves for injection into plasmas. In this paper we will describe the potential advantages of applying this technology to superconducting ECR ion sources as well as designs for doing so with VENUS.

Slides TUXO01 [18.302 MB]

TUXO02

An Experimental Study of ECRIS Plasma Stability and Oscillation of Beam Current

ECR, ion, ion-source, ECRIS

5

O.A. Tarvainen, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, V. Toivanen
JYFL, Jyväskylä, Finland
C.M. Lyneis, M.M. Strohmeier
LBNL, Berkeley, California, USA

The stability of oxygen ion beams extracted from ECR ion sources has been studied with the superconducting ion source VENUS at LBNL and with the A-ECR type 14 GHz ECRIS at JYFL. Discrete Fourier transform has been used for characterizing beam current oscillations in kHz range exhibited by both ion sources. The effect of source parameters on the frequency and amplitude of the oscillations is discussed. It was found that double frequency heating affects the oscillation frequency, biased disc can be used to mitigate the amplitude of beam current fluctuations, increasing B-minimum results to pronounced instabilities and operating the ion source with significantly higher mirror ratio than suggested by ECRIS scaling laws yields the most stable ion beams. It is argued that the observed beam current fluctuations are correlated with plasma instabilities. A 'roadmap' for identifying the plasma instability mechanisms responsible for beam current fluctuations is presented.

Slides TUXO02 [2.195 MB]

TUXO03

Two-frequency Heating Technique for Stable ECR Plasma

ion, ECR, ion-source, ECRIS

10

A. Kitagawa, M. Muramatsu
NIRS, Chiba-shi, Japan
S. Biri, R. Rácz
ATOMKI, Debrecen, Hungary
T.F. Fujita
National Institute of Radiological Sciences, Chiba, Japan
Y. Kato
Osaka University, Graduate School of Engineering, Osaka, Japan
N. Sasaki, W. Takasugi
AEC, Chiba, Japan

As a method to improve highly charged ion production, a technique to feed multiple microwaves with different frequencies is well-known. However the reason is not made sufficiently clear. Our group studied with two frequencies close together with a power of 600 W over by 18 GHz NIRS-HEC ECR ion source installed in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). As a result, it was revealed that the improvement of output beam current depends on the total power. In this case it seems that the two-frequency heating technique carries the advantage that the plasma instability at high microwave power is relieved. The effectiveness of an additional microwave depends on its frequency. It is necessary to optimize an additional frequency precisely; several tens MHz step against 18 GHz. The optimized frequency is directly influenced by the magnetic configuration. The necessary requirements for an additional microwave and the procedure of optimization in order to obtain a large advantage will be discussed.

Slides TUXO03 [1.590 MB]

TUYO01

Experimental Study of Temperature and Density Evolution During Breakdown in a 2.45 GHz ECR Plasma

coupling, diagnostics, electron, ion

13

O.D. Cortázar, A. Megía-Macías, A. Vizcaíno-de-Julián
ESS Bilbao, LEIOA, Spain

An experimental study of temperature and density evolution during breakdown in off-resonance ECR hydrogen plasma by time resolved Langmuir probe diagnostic is presented. Under square 2.45 GHz microwave excitation pulses with a frequency of 50 Hz and relative high microwave power, unexpected transient temperature peaks that reach 18 eV during 20 μs are reported at very beginning of plasma breakdown. Decays of such peaks reach final stable temperatures of 5 eV at flat top microwave excitation pulse. Evidence of interplay between incoming power and duty cycle giving different kind of plasma parameters evolutions engaged to microwave coupling times is observed. Under relative high power conditions where short microwave coupling times are recorded, high temperature peaks are measured. However, for lower incoming powers and longer coupling times, temperature evolves gradually to a higher final temperature without peaking. On the other hand, the early instant where temperature peaks are observed also suggest a possible connection with preglow and superadiabatic processes during breakdown in ECR plasmas.

Slides TUYO01 [6.674 MB]

TUYO02

Control of the Plasma Transversal Losses, Caused by MHD Instabilities, in Open Mirror Magnetic Trap of the ECRIS: Recent Experiments on SMIS 37 Setup

ion, ECR, ion-source, electron

18

V. Sidorov, I. Izotov, S. Razin, V. Skalyga, V. Zorin
IAP/RAS, Nizhny Novgorod, Russia

Funding: This work was partially performed in the framework of the Federal Targeted Program 'Scientific and Educational Personnel of the Innovative Russia' for 2009-2013
This work is a continuation of the experiments described in [1, 2] and aimed at the investigation of the new conceptions of MHD stabilization of plasma in open axisymmetric traps, specifically, it is aimed at the investigation of the shear flow influence on the transport control in open mirror traps. As in previous experiments, shear flow was created by limiter-electrode with bias potential according to the vacuum chamber. Plasma density structure in radial and azimuthal directions was studied. Mode structure of the perturbations was investigated. Substantial sharp shift of the plasma density maximum to the system axis with bias potential growth was demonstrated. It was shown, that the value of the bias potential that corresponds to the plasma density profile shift grows with the magnetic field growth that can be interpreted as the electron temperature growth. Some theoretical estimations of the influence of the transversal losses decrease on plasma parameters were made.
[1] A.Sidorov, P.Bagryansky, A.Beklemishev et al. Trans. Fusion Sci. and Technology, 59, 112, (2011).
[2] I.Izotov, S.Razin, A.Sidorov et al. Rev. Sci. Instrum., 83, 02A318 (2012).

Slides TUYO02 [1.542 MB]

TUYO03

Secondary-electron-enhanced Plasma as an Alternative to Double/Variable-frequency Heating in ECRIS

ECRIS, ion, electron, experiment

22

K.E. Stiebing
IKF, Frankfurt-am-Main, Germany
S. Dobrescu, L. Schächter
IFIN, Magurele- Bucuresti, Romania

As "double frequency heating" (DFH) now has become the method of choice to optimize the output from the newest generation ECRIS, it was a challenge to compare this method with the comparatively cheap method of "metal dielectric" (MD) structures introduced into the plasma chamber, which has also proven to strongly enrich the plasma with electrons that are effectively trapped and heated. Two RF-systems have been launched to the 14 GHz ECRIS, however, not allowing RF-differences as large as 1.5 GHz as demanded for DFH. Therefore the source was operated in a "frequency tuning" mode (FT) by optimizing the frequency difference by the output of Ar¹⁴⁺ ions. The data without and with MD-configuration are compared and related to data for the DFH. On the basis of Bremsstrahlung radiation spectroscopy and charge state analysis, it turned out that the FT-mode does not change the source performance substantially. The measured effects are in the order of 20% to 30% as reported elsewhere. In contrast to this, the enhancement gained by the MD method is much higher. The measured enhancement ratios even surpass those reported for real double frequency heating.

Slides TUYO03 [5.642 MB]

TUYO04

Neutral Gas Temperature Measurements of a Radio Frequency Micro-thruster

ion, electron, background, vacuum

25

A.D. Greig, R.W. Boswell, C. Charles, R.P. Hawkins
SP3, Canberra, Australia
M.D. Bowden, Y.C. Sutton
The Open University, Milton Keynes, United Kingdom

A radio frequency (13.56 MHz) capacitively coupled cylindrical argon plasma discharge was analysed using optical emission spectroscopy (OES) for various powers and pressures in the ranges 10 W to 40 W and 0.5 Torr to 5 Torr. Trace amounts of nitrogen were added to the discharge to estimate the temperature of the neutrals using rovibrational band matching of the 2^nd positive system of nitrogen and the 1^st negative system of nitrogen ions. Comparing simulated computer generated spectra of these bands to experimentally measured spectra determined the rotational and vibrational temperatures of the nitrogen, from which the temperature of the neutrals was inferred by assuming the rotational temperature was the same as the neutral gas temperature.

Slides TUYO04 [1.341 MB]

TUZO03

New Extraction Design for the JYFL 14 GHz ECRIS

extraction, simulation, ion, space-charge

34

V. Toivanen, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, O.A. Tarvainen
JYFL, Jyväskylä, Finland

Funding: VT acknowledges the financial support of the Ehrnrooth foundation.
A new extraction system has been designed and constructed for the JYFL 14 GHz ECRIS at the Department of Physics, University of Jyväskylä (JYFL). The goal of the new design is to improve the performance of the ion source and increase the transmission efficiency of the low energy beam transport and the accelerator. The new extraction system is designed to be able to handle higher beam currents, yield better beam quality and offer more tuning flexibility. The design was made with the aid of simulations performed with the IBSimu code. The suitability of the code for this task was verified by simulating the old extraction system and good agreement between simulations and measurements was achieved. The new extraction system has been constructed, installed and tested. The new design, simulations and the first measurement results will be presented.

Slides TUZO03 [4.470 MB]

TUPP04

Design of a Compact ECR Ion Source for Various Ion Production

ion, extraction, ion-source, ECR

49

M. Muramatsu, S. Hojo, Y. Iwata, K. Katagiri, A. Kitagawa, Y. Sakamoto, S. Sato
NIRS, Chiba-shi, Japan
A.G. Drentje
KVI, Groningen, The Netherlands
T.F. Fujita
National Institute of Radiological Sciences, Chiba, Japan

Compact ECR ion source with all permanent magnets, so called Kei2, was developed for high energy carbon ion therapy facility at National Institute of Radiological Sciences. Kei2 source was design for production of only carbon ion for medical treatment. A copy of Kei2, so called KeiGM is used for Gunma University. Kei series are optimized for carbon ion production. In order to produce various ion beams for research, we design a new compact ECR ion source, so called Kei3. Kei3 is designed based on previous Kei series. In addition, there are three important points: 1) Movable beam extraction system for various extraction current densities, 2) An evaporator and MIVOC method for production of ions from solid materials and metal, and 3) Biased disk method and double frequency heating method for heavier ions. Same permanent magnets and microwave system will be used for easy maintenance and the cost effectiveness. Design of the Kei3 source will be described in this paper.

TUPP05

Charge-breeding at the Texas A&M University Cyclotron Institute

ion, injection, ECRIS, cyclotron

51

D.P. May
Texas A&M University Cyclotron Institute, College Station, Texas, USA
J.E. Ärje
JYFL, Jyväskylä, Finland
G. Tabacaru
Texas A&M University, Cyclotron Institute, College Station, USA

The Cyclotron Institute of Texas A&M University is currently involved in an upgrade that is intended to produce beams of radioactive ions suitable for injection into the K500 superconducting cyclotron. As an integral part of this upgrade an electron-cyclotron-resonance ion source (CB-ECRIS) has been specially constructed by Scientific Solutions of San Diego, California for charge-breeding. This CB-ECRIS operates at 14.5 GHz and incorporates a hexapole of the Halbach style. Since radial injection of microwave power is ruled out, this presents special problems for the axial injection of low-charge-state ions for charge-breeding. Efforts at charge-breeding with stable ions will be presented as well as plans for the injection of low-charge-state, radioactive ions from cyclotron-driven ion guides, one for light radioactive ions and one for heavy radioactive ions.

TUPP08

Design Report of the AISHA Ion Source for Hadron Therapy Facilities

ECR, ion, injection, hadrontherapy

54

G. Ciavola, L. Andò, L. Celona, S. Gammino, D. Mascali
INFN/LNS, Catania, Italy
G. Ciavola
CNAO Foundation, Milan, Italy
D. Mascali
CSFNSM, Catania, Italy

Different facilities for hadrontherapy have been built or designed in the recent past and Italy is present in the field either with synchrotron-based and with cyclotron-based facilities. For both types of accelerators the availability of high brightness multiply charged ion beams is essential and R&D efforts in this subject are increasing. In particular at the CNAO, proton and carbon ion beams will be accelerated up to 400 AMeV by a synchrotron and the beam injection is guaranteed by two identical ECR sources of the SUPERNANOGAN family modified according to the specifications we set. Optimisation of beam emittance and intensity is of primary importance to obtain the necessary current in the RFQ-LINAC and future facilities may require much better performances in terms of beam brightness than the ones provided by such commercial ECRIS. A hadron therapy center is going to be built in Catania and the R&D related to the injector has already started within the frame of a collaboration between the Regional Authority and INFN. The results of the research carried out at INFN-LNS will be presented along with the design of a relatively compact ECR ion source operating at 18 GHz, named AISHA.

TUPP13

Development of Intense Proton ECR Ion Sources at IMP

proton, ion, extraction, ECR

64

Z.M. Zhang, Z.W. Liu, H.Y. Ma, L.T. Sun, Q. Wu, Y. Yang, W.H. Zhang, X.Z. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

Since 1997, there have been two ECR ion sources for producing intense proton beam developed at Institute of Modern Physics (IMP). In 1999, a high current 2.45 GHz ECR proton source for Lanzhou university neutron generator, was constructed and tested at IMP. A mixed ion (H¹⁺ + H²⁺ + H³⁺) beam current of 110 mA with CW mode was delivered from a single aperture of 6mm diameter with microwave power of 600 W at the extraction voltage of 22 kV. Recently a new pulsed proton source has been designed and built at IMP for the CPHS (Compact Pulse Hadron Source) facility in Tsinghua University. Now this source is under commissioning for 60 mA proton beam with 50 keV energy. The long time running stability and beam emittance have been tested and the results are well up to the requirements of CPHS. In this paper, after a short review of the proton ion source for Lanzhou University, the design and test results of the CPHS proton source as well as the LEBT will be presented. The design of the proton ion source and the LEBT for the Chinese ADS project will also be discussed in the contents.

WEXO02

Recent Developments and Electron Density Simulations at the ATOMKI 14.5 GHz ECRIS

electron, ion, simulation, ECRIS

77

S. Biri, R. Rácz
ATOMKI, Debrecen, Hungary
J. Pálinkás
University Debrecen, Debrecen, Hungary

The 14.5 GHz ECR ion source of ATOMKI is a standard room-temperature ECRIS devoted for plasma diagnostic studies, for atomic physics research and also serves as a particle source with wide range of elements for surface treatments. From the beginning lots of technical modifications and developments have been carried out on the ion source. The changes aimed the increasing of the beams charge, intensity and the widening of the ion choice. Other modifications were done to develop special, non-standard operation modes or to produce peculiar plasmas or beams. Recently the original NdFeB hexapole was exchanged by a new one and new iron plugs were calculated, designed and installed at the injection side of the source. The resulted stronger magnetic trap has shown significant effect on the beam intensity and on the charge states distribution. The new magnetic configuration was re-calculated by the TrapCAD code developed by our group. The spatial movement and energy evolution of a high number of electrons were followed in the calculation. A post-calculation energy filtering carried out for the lost and non-lost electrons reveals numerous interesting and important information in 3D.

Slides WEXO02 [11.678 MB]

WEXO03

Numerical Modeling of Ion Production in ECRIS by using the Particle-in-Cell Method

ion, extraction, ECR, ECRIS

82

V. Mironov, J.P.M. Beijers
KVI, Groningen, The Netherlands

To better understand the physical processes in ECRIS plasmas, we developed a Particle-in-Cell code that follows the ionization and diffusion dynamics. The basic features of the numerical model are given elsewhere*. An electron temperature of about 1 keV is needed to reproduce the experimentally observed performance of our 14 GHz ECR source. We assume that a pre-sheath is located outside the ECR zone, where the ion acceleration toward the walls occurs. Electric field inside the ECR zone is supposed to be zero. The ion production is modeled assuming the ion confinement by a ponderomotive barrier formed at the boundary of the ECR zone. The barrier height is defined by the RF radiation density at the electron resonance layer and is taken as an adjustable parameter; when the plasma becomes overdense, we set the barrier value to zero. With these assumptions, we are able to reproduce the main features of ECRIS performance, such as the saturation and decrease of highest charge state currents with increasing gas pressure, as well as response to an increase of injected RF power. Afterglow and frequency-tuning effects can be explained by introducing the ponderomotive barrier.
* V. Mironov and J. P. M. Beijers, "Three-dimensional simulations of ion dynamics in the plasma of an electron cyclotron resonance ion source", Phys. Rev. ST Accel. Beams 12, 073501 (2009).

Slides WEXO03 [7.032 MB]

WEXO04

Proton Beams Formation from Dense Plasma of ECR Discharge sustained by 37.5 GHz Gyrotron Radiation

extraction, ion, proton, emittance

85

V. Skalyga, I. Izotov, S. Razin, V. Sidorov, V. Zorin
IAP/RAS, Nizhny Novgorod, Russia
T. Kalvas, H. A. Koivisto, O.A. Tarvainen
JYFL, Jyväskylä, Finland

Funding: Work was performed in frame of realization of federal targeted program "Scientific and pedagogical labor force for an innovative Russia" for 2009-2013 yy.
Operation of modern high power accelerators often requires production of intense beams of hydrogen ions. Newer facilities aiming at outperforming the previous generation accelerators are usually designed for higher beam currents. Meeting the demand for hydrogen ion beams with higher intensity and low transverse emittance is, therefore, becoming increasingly difficult problem. Present work is devoted to experimental investigation of proton beams production from dense plasma (Ne>10¹³ cm^-3) of ECR discharge sustained by 37.5 GHz, 100 kW gyrotron radiation at SMIS 37 facility at IAP RAS. Different extraction system configurations were used. It was demonstrated that ultra bright proton beam with 4.5 mA current and 0.1 π·mm·mrad normalized emittance (brightness=45 A/(π·mm·mrad)²) can be formed with 1-hole (1 mm in diameter) extraction. For production of high current beams a 13-hole extractor was used. 200 mA and 1.1 π·mm·mrad normalized emittance proton beam was obtained. A possibility of further beam parameters enhancement by developing of extraction system and its power supply is discussed. It was shown that in generated proton beams H²⁺ component was less than 6%.

Slides WEXO04 [2.512 MB]

WEXO05

Effect of Source Tuning Parameters on the Plasma Potential of Heavy Ions and its Influence on the Longitudinal Optics of the High Current Injector

ion, rfq, electron, emittance

90

G.O. Rodrigues, D. Kanjilal, P.S. Lakshmy, A. Mandal, Y. Mathur, A. Roy
IUAC, New Delhi, India
R. Baskaran
IGCAR, Channai, India

Plasma potentials for various heavy ions have been measured using the retarding field technique in the 18 GHz High Temperature Superconducting ECR ion source, PKDELIS. The influence of various source parameters viz., RF power, gas pressure, magnetic field, negative DC bias and gas mixing on the plasma potential is studied. It is observed that the plasma potentials are decreasing for increasing charge states and a mass effect is clearly observed for the ions with similar operating gas pressures. In the case of gas mixing, it is observed that the plasma potential minimises at an optimum value of the gas pressure of the mixing gas and the mean charge state maximises at this value. The energy spread arising from the plasma potential influences the longitudinal optics of the high current injector in terms of increased phase spread which deteriorates the transmission through the RFQ. Details of the measurements carried out as a function of various source parameters and its impact on the longitudinal optics are presented.

Slides WEXO05 [11.394 MB]

WEYO02

Experimental Results: Charge-state and Current-density Distribution at the Plasma Electrode of an ECR Ion Source

ion, extraction, ion-source, ECR

101

L. Panitzsch, T. Peleikis, M. Stalder, R.F. Wimmer-Schweingruber
IEAP, Kiel, Germany

We have measured the current-density in very close vicinity (15 mm downstream) of the plasma electrode of our hexapole-geometry electron-cyclotron-resonance ion source (ECRIS). For this, we equipped our 3D-movable puller electrode with a customized Faraday Cup (FC) inside. To achieve high spatial resolution we reduced the aperture of the puller electrode to only 0.5 mm. Thus, the source-region of the extracted ion beam is limited to a very small area of the plasma electrode's hole (d = 4 mm). The information about the charge-state distribution and the current density in the plane of the plasma electrode is conserved in the ion beam and was scanned by remotely moving the small-aperture puller electrode (incl. FC) across the aperture of the plasma electrode. From additional m/q- measurements for the different positions we can deduce that different ion charge-states are grouped into bloated triangles of different sizes but with the same orientation in the plane of the plasma electrode with the current density peaking at the centre. This confirms simulations by various groups as well as some emittance measurements, but adds spatial resolution for the different charge-states.

Slides WEYO02 [2.298 MB]

WEYO03

Ion Beam Extraction from Magnetized Plasma

ion, electron, extraction, ion-source

106

P. Spädtke, R. Lang, J. Mäder, F. Maimone, J. Roßbach, K. Tinschert
GSI, Darmstadt, Germany

With increasing the total extracted current for any ion source, the optimisation of the extraction system becomes more important, because of the space charge effect. Several attempts have been made in the past to simulate the extraction from an Electron Cyclotron Resonance Ion Source (ECRIS) in a correct way. Most of these attempts failed, because they were not able to reproduce the experimental results. The best model up to now is given by the following procedure: tracing the magnetic field lines through the extraction aperture, looking where these field lines are coming from; using these coordinates of the magnetic field line as starting points for ions to be extracted; the initial current of each trajectory is determined by theoretical assumptions about the plasma or by a plasma simulation; Child's law is applicable locally only in direction of the magnetic field, if no emission limited flow is present.

Slides WEYO03 [16.955 MB]

WEZO01

Status of the SEISM Experiment

injection, extraction, resonance, ECR

111

M. Marie-Jeanne, J. Angot, P. Balint, C. Fourel, J. Giraud, J. Jacob, T. Lamy, L. Latrasse, P. Sortais, T. Thuillier
LPSC, Grenoble Cedex, France
C. Daversin, F. Debray, C. Trophime, S. Veys
GHMFL, Grenoble, France
I. Izotov, V. Skalyga, V. Zorin
IAP/RAS, Nizhny Novgorod, Russia

Funding: This work has been supported by the EuroMagNET II under the EU contract number 228043 and by the European Commission Framework Programme 7 Design Study: EUROnu, Project Number 212372.
LPSC and LNCMI (Laboratoire National des Champs Magnétiques Intenses) of Grenoble have developed the first and unique magnetic confinement structure in the world that allows a closed 60 GHz ECR zone, using high field magnet technologies. The magnetic structure has been validated for 28 GHz resonance and a closed 1 T iso-B surface was measured. Calculated and measured field maps were carefully compared in order to determine an operation range for 28 GHz plasma tests. A whole test bench, including high pressure water for helix cooling, intense currents (up to 15 kA) for helix powering and a beam line with mass separation is under construction at LNCMI. This contribution presents the status of the experiment, hopefully including the results of the first beam tests scheduled in September. The 350 kW - 60 GHz gyrotron has been built at IAP, the status of its operation will be shown.

Slides WEZO01 [11.245 MB]

WEZO02

Design of new 18 GHz ECR for RIKEN RIBF

ion, ion-source, ECRIS, solenoid

114

K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi
RIKEN Nishina Center, Wako, Japan

In RIKEN RIBF, we plan to install a new 18 GHz ECR ion source, which supply the intense beam of highly charged heavy ion beam into the linear accelerator RILAC. By equipping two ion sources, it is expected to be able to develop new beams while we produce the beam for the experiment of RIBF. Based on the structure of 18 GHz ECR ion source which have been developed in RIKEN, this ion source has additional features as follows:

Owing to three solenoid coils, Bext can be adjusted while Bmin is fixed to an optimum value.
We adopt the variable frequency (17.2-18.4 GHz) RF power source. Therefore, further enhancement of the beam intensity is expected because the frequency band suited to a size of plasma chamber is selectable,
In order to simplify the maintenance work, we improved a structure of the chamber.

In this contribution, we report the design of new ion source in detail.

Slides WEZO02 [10.113 MB]

WEZO03

Recent Results of PHOENIX V2 and New Prospects with PHOENIX V3

ion, ECR, booster, operation

117

T. Thuillier, J. Angot, T. Lamy, M. Marie-Jeanne
LPSC, Grenoble Cedex, France
C. Barue, C. Canet, M. Dupuis, P. Lehérissier, F. Lemagnen, L. Maunoury, O. Osmond
GANIL, Caen, France
C. Peaucelle
IN2P3 IPNL, Villeurbanne, France
P. Spädtke
GSI, Darmstadt, Germany

Funding: This work is partially funded by the European Commission under the 7th Framework Programme Grant Agreement 283745 (CRISP)
The 18 GHz PHOENIX V2 ECRIS is running since 2010 on the heavy ions low energy beam transport line (LEBT) of SPIRAL2 installed at LPSC Grenoble. PHOENIX V2 will be the starting ion source of SPIRAL 2 at GANIL. The status and future developments of this source are presented in this paper. Recent studies with Oxygen and Argon beams at 60 kV have demonstrated reliable operation at 1.3 emA of O⁶⁺ and 200 eμA of Ar¹²⁺. Metallic ion beam production has been studied with the Large Capacity Oven developed by GANIL and 20 eμA of Ni¹⁹⁺ have been obtained. In order to improve further the beam intensities for Spiral2, an economical upgrade of the source named PHOENIX V3 has been recently decided by the project management. The goal is to double the plasma chamber volume from 0.6 to 1.2 liter by increasing the chamber wall radius, keeping the whole magnetic confinement intensity unchanged. The PHOENIX V3 magnetic design will be presented along with a status of the project.

Slides WEZO03 [8.818 MB]

WEPP02

Relationship of Performance and RF Resonance Modes

ion, ECR, ion-source, resonance

121

T. Hattori, A. Kitagawa, M. Muramatsu
NIRS, Chiba-shi, Japan
N. Hayashizaki
RLNR, Tokyo, Japan

The performance of Electron Cyclotron Resonance (ECR) ion source depends on the operation frequency, the magnetic mirror field, the maltipole field, the mirror ratio, the ECR zone and others. We studied the relationship of performance and operation frequency in ECR ion source (HiECR-3). The performance (beam intensity of Ar⁹⁺ ion) was measured according to change of frequency from 9.7 to 11.7 GHz in fixed magnetic field of HiECR ion source. We measured resonant frequencies of plasma chamber of HiECR ion source in condition of no plasma (current of mirror coils is zero). The data of intensity of Ar⁹⁺ related to measured resonant frequencies. Their resonant modes were checked with a 3D electromagnetic simulator (High Frequency Structure Simulator). As a result, it became clear that the performance of the ion source depends on electric-field distribution of the RF resonant mode.

WEPP03

Plasma Instability in the Afterglow of ECR Discharge Sustained in a Mirror Trap

electron, ion, ECR, detector

125

I. Izotov, A. Mansfeld, V. Skalyga, V. Zorin
IAP/RAS, Nizhny Novgorod, Russia
T. Grahn, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, P. Peura, O.A. Tarvainen, V. Toivanen
JYFL, Jyväskylä, Finland

Funding: Work was performed in frame of realization of federal targeted program "Scientific and pedagogical labor force for an innovative Russia" for 2009-2013 yy.
A number of studies have been devoted to the investigations of plasma decay in ECR heated discharges confined in a mirror magnetic trap. The motivation of this work is to study plasma instabilities causing perturbations of ion current during the plasma decay. Present work is devoted to time-resolved diagnostics of non-linear effects observed during the afterglow plasma decay of an 14 GHz Electron Cyclotron Resonance Ion Source (ECRIS) at JYFL operated in pulsed mode. Plasma instabilities causing perturbations of extracted ion current during the decay were observed and studied. It is shown that these perturbations are associated with precipitation of high energy electrons along the magnetic field lines and strong bursts of bremsstrahlung emission. The effect of ion source settings on the onset of the observed instabilities was investigated. Based on the experimental data and estimated plasma properties it is assumed that the instabilities are of cyclotron type. The conclusion is supported by a comparison to other type of plasma devices (SMIS 37, IAP RAS) exhibiting similar characteristics but operating in a different plasma confinement regime.

WEPP15

Metal Ion Beam Production with Improved Evaporation Ovens

ion, operation, ECRIS, ion-source

140

K. Tinschert, R. Lang, J. Mäder, F. Maimone, J. Roßbach
GSI, Darmstadt, Germany

Most of the ion beams delivered by the ECR ion sources at the GSI accelerator facilities are produced from materials in the solid state, which must be transformed into the gaseous state to feed the plasma. The well established method of thermal evaporation has been used by means of two types of resistively heated ovens for metals and solid compounds. The main goal of development is to improve their versatility in terms of lifetime, durability, efficiency, and extended temperature range. Recent investigations and developments include the use of alternative materials for oven components. The main focus has been on the further development of the high temperature oven. A modular construction with improved mechanical dimensional accuracy for more precise and easier mounting has been established. Its optimization for stable long time operation has been continued leading to a lifetime of 6 days for evaporation of Ti at 1750°C. Furthermore the temperature limit could be extended to 2300°C. In addition to the improvements in evaporation technology the technique of microwave frequency tuning could be successfully applied for metal ion operation leading to enhanced ion beam intensities.

WEPP16

Experimental Studies on the ALISES Ion Source at CEA Saclay

ion, ion-source, electron, extraction

143

O. Tuske, O. Delferrière, Y. Gauthier, R. Gobin, F. Harrault, J.L. Jannin
CEA/DSM/IRFU, France
S. Nyckees
CEA/IRFU, Gif-sur-Yvette, France

The ALISES ion source was originally designed to reduce beam emittance at RFQ entrance by shortened the length of the LEBT. A wide opened magnetic coil at ground potential produces the fringe field needed for the ECR heating at 2.45 GHz frequency. The first part describes the commissioning of the source: Penning discharges inside the accelerating column make the high voltage power supply collapse. Experimental tests with kapton films while discharges occur, and simulations with OPERA-3D code have shown great similarities to detect the location of those discharges and allow us to make the ion source work. The second part of this paper will present the result of low intensity light ion beam production versus the plasma chamber length and radius. Those very preliminary tests give us indications to reduce the ion source dimensions.

Poster WEPP16 [2.556 MB]

WEPP17

A Multi-Sample Changer Coupled to an ECR Source for AMS Experiments

laser, ion, ECR, ion-source

146

R.C. Vondrasek, T. Palchan, R.C. Pardo, C.E. Peters, M.A. Power, 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.
A project using Accelerator Mass Spectrometry (AMS) at the ATLAS facility to measure neutron capture rates on a wide range of actinides in a reactor environment is underway. This project will require the measurement of a large number of samples previously irradiated in the Advanced Test Reactor at Idaho National Laboratory. The AMS technique at ATLAS is based on production of highly-charged positive ions in an electron cyclotron resonance ion source (ECRIS) followed by acceleration in the ATLAS linac. The sample material is introduced into the plasma via laser ablation. This should limit the dependency of material feed rates upon the source material composition as well as minimize cross-talk between samples. A new multi-sample changer has been constructed allowing rapid changes between samples. The sample changer has 20 positions and is capable of moving from one sample to the next in one minute. Details of the sample changer design and operation will be presented.

THXO01

Optimization of the New SC Magnetic Structure Design with a Hybrid Magnet

injection, solenoid, ECRIS, sextupole

149

D. Xie, W. Lu, L.Z. Ma, L.T. Sun, X.Z. Zhang, H.W. Zhao, L. Zhu
IMP, Lanzhou, People's Republic of China

In the development of the next generation ECRISs, so far either a set of full NbTi or full Nb₃Sn magnets has been proposed to construct the magnet system. However, the single set of magnets may not be the optimum in terms of the field strength and configuration. An optimization of the new SC magnetic structure with a set of hybrid magnets (NbTi and Nb₃Sn) is being investigated. With the hybrid magnet the optimized new magnetic system is capable of producing field maxima of 9.0 T on axis and 4.0 T at the plasma wall, which are 30 and 10% higher than the previously proposed magnetic structure to be built with a set of full NbTi magnets. In addition, the axial length of the optimized magnetic structure has been slightly shrunk resulting in a more compact system. This new magnetic field profile is high enough for operation frequency up to 56 GHz. The design features and the preliminary force/stress analyses of the optimized new SC magnetic structure will be presented and discussed.

Slides THXO01 [2.603 MB]

THXO02

Current Developments of the VENUS Ion Source in Research and Operations

ion, extraction, cyclotron, ion-source

153

J.Y. Benitez, K.Y. Franzen, C.M. Lyneis, L. Phair, M.M. Strohmeier
LBNL, Berkeley, California, USA
G. Machicoane
FRIB, East Lansing, Michigan, USA
L.T. Sun
IMP, Lanzhou, People's Republic of China

The VENUS ion source functions as a research and development tool in the ECR community as well as an injector for LBNL's 88-Inch cyclotron. In order to meet the needs of both the ECR community and users at the 88-Inch cyclotron, technology such as ovens and a sputter probe have been developed for introducing metals into the plasma. Using a modified high temperature oven, VENUS has produced 450 eμA of ²³⁸U³³⁺ and 400 eμA of ²³⁸U³⁴⁺, twice the required Uranium beam current needed for FRIB. In addition, after upgrading its high voltage capabilities VENUS produced 11emA of ⁴He²⁺, a capability that remains unparalleled by other ECR ion sources. In addition to its recent record high intensities VENUS is also being developed to deliver low intensity, ultra high charge state ions for the cocktails beams, where many species are produced simultaneously for use by the BASE Facility. ¹²⁴Xe⁴³⁺ is now in regular production for the 16 MeV/u cocktail, and development of ²⁰⁹Bi⁵⁶⁺ for the 10 MeV/u cocktail is in progress and has been accelerated through the 88-Inch cyclotron. This paper presents the latest work towards integrating the VENUS ion source into our research and operational goals.

Slides THXO02 [8.391 MB]

THYO01

Operation of an ECRIS Charge State Breeder at TRIUMF

ion, background, experiment, ECR

163

F. Ames, R.A. Baartman, P.G. Bricault, K. Jayamanna, A. Mjøs
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

After initial commissioning of the charge state breeder for radioactive ions at the TRIUMF/ISAC facility further tests on the performance of the system have been performed. One of the major problems found was the high background of stable ions from the ECR source, mainly C, N, O, Ar, Fe, Ni, C and Cr. The main source of those is the residual gas and sputtered material from the plasma chamber wall and from the surrounding electrodes. Although their intensity is small it can be orders of magnitude more than the intensity from the radioactive ions. Therefore, the original stainless steel plasma chamber of the Pantechnik PHOENIX ECR source has been exchanged to aluminium with an ultra pure aluminium coating, all electrodes for injection and extraction of the ions have been replaced with aluminium and the iron joke at the extraction side, which is part of the vacuum system in the PHOENIX source has been coated as well. This combined effect has reduced the amount of background ions substantially. Detailed results on the performance of the source after those changes will be presented.

Slides THYO01 [1.634 MB]

THYO02

LPSC PHOENIX ECR Charge Breeder Beam Optics and Efficiencies

extraction, ion, injection, emittance

167

J. Angot, T. Lamy, M. Marie-Jeanne, P. Sortais, T. Thuillier
LPSC, Grenoble Cedex, France

The PHOENIX ECR charge breeder characteristics (efficiency and charge breeding time) were measured at CERN-ISOLDE and LPSC, they were considered as sufficient to allow its setup on various facilities (TRIUMF-Canada/GANIL-SPIRAL2-France/SPIRAL1). The developments performed at the Argonne National Laboratory (USA) have shown that the ECR charge breeder efficiencies could be much higher than the ones obtained with PHOENIX, without major differences between the two devices. We have tried to study the possible reasons of such different results in order to improve the PHOENIX charge breeder characteristics. The transmission value of the n+ beam line has been measured to be as low as 30%. Emittances of the total beam extracted from the source and of some analyzed beams (after the magnetic spectrometer) have been measured and will be presented. Simulations have shown a too low vertical acceptance at the center of the dipole. Simulations and experimental results will be presented to show how an additional Einzel lens inserted just before the dipole have drastically improve the beam transmission. The impact of this new beam transport on efficiency results will be presented.

Slides THYO02 [4.337 MB]

THYO04

Performance of the ANL ECR Charge Breeder with Low Mass Beams

ion, injection, ECR, ion-source

177

R.C. Vondrasek, S.V. Kutsaev, R.C. Pardo, R.H. Scott
ANL, Argonne, USA
P. Delahaye, L. Maunoury
GANIL, Caen, France

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The Californium Rare Ion Breeder Upgrade (CARIBU) of the ATLAS superconducting linac facility aims at providing low-energy and reaccelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. These beams are obtained from fission fragments of a Cf-252 source, thermalized and collected into a low-energy particle beam by a helium gas catcher, mass analyzed by an isobar separator, and charge bred with an ECR ion source for acceleration in ATLAS. The charge breeding program had focused on optimizing beams in the mid-mass range, achieving high charge breeding efficiencies of both gaseous and solid species including 14.7% for the radioactive species ¹⁴³Ba²⁷⁺. In an effort to better understand the charge breeding mechanism, we recently focused on the low-mass species sodium and potassium which up to present have been difficult to charge breed efficiently. Charge breeding efficiencies of 10.1% for ²³Na⁷⁺ and 17.9% for ³⁹K¹⁰⁺ were obtained injecting stable Na⁺ and K⁺ beams from a surface ionization source. Details of these studies will be presented as well as simulations detailing the injection of the low charge state beams into the charge breeder.

Slides THYO04 [9.178 MB]

FRXA01

High Intensity Beam Production at CEA/Saclay for the IFMIF Project

rfq, extraction, emittance, solenoid

182

R. Gobin, G. Adroit, D. Bogard, N. Chauvin, O. Delferrière, Y. Gauthier, P. Girardot, F. Harrault, J.L. Jannin, D. Loiseau, P. Mattei, A. Roger, F. Senée, O. Tuske
CEA/DSM/IRFU, France

At CEA/Saclay, IRFU institute is in charge of the design, construction and characterization of the 140 mA continuous deuteron Injector for the IFMIF project. This injector includes the source and the low energy beam line (LEBT) with its own diagnostics. The Electron Cyclotron Resonance (ECR) ion source operates at 2.45 GHz and the 2 m long LEBT is based on 2 solenoids. Krypton gas injection in the beam line is foreseen in order to reach a high level of space charge compensation for the beam matching at the RFQ entrance. During the last months hydrogen beam has been produced in pulsed and continuous mode and the beam diagnostics have been installed and commissioned. Recently a 125 mA-100 keV pulsed deuteron beam has been produced with a 1% duty cycle. In this article, the high intensity proton and deuteron beam characterization will be presented.

Slides FRXA01 [9.797 MB]

FRXA02

All Permanent Magnet ECR Ion Source Development and Operation Status at IMP

ion, ion-source, ECR, permanent-magnet

185

L.T. Sun, Y. Cao, J.Q. Li, J.Y. Li, B.H. Ma, H. Wang, J.W. Xia, D. Xie, W.H. Zhang, X.Z. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

All permanent magnet ECR ion sources have many advantages over traditional ECR ion sources composed of several axial room temperature solenoids and one permanent magnet hexapole magnet, which make them the first choice for many heavy ion facilities and platforms. At IMP, three types of all permanent magnet ECR ion sources have been built for different applications, i.e. the very compact ECR ion source LAPECR1 for intense mono or multi charge state ion beam production, the LAPECR2 ion source installed on the 320 kV high voltage multidisciplinary platform, and the LAPECR3 ion source dedicated to C⁵⁺ beam production for the cancer therapy facility. In this paper, after a general discussion of the ion sources' design, the applications and the operation status of the IMP all permanent magnet ECR ion sources will be presented.

Slides FRXA02 [6.380 MB]

FRXA03

Laser Ablation of Actinides into an Electron Cyclotron Resonance Ion Sources for Accelerator Mass Spectroscopy

laser, ion, ECR, target

190

T. Palchan, F.G. Kondev, S.A. Kondrashev, C. Nair, R.C. Pardo, R.H. Scott, R.C. Vondrasek
ANL, Argonne, USA
W. Bauder, P. Collon
University of Notre Dame, Indiana, USA
J.F. Berg, T. Maddock, G. Palmotti, M. Salvatores, G. Youinou
INL, Idaho Falls, Idaho, USA
G. Imel
ISU, Pocatello, Idaho, USA
M. Paul
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
M. Salvatores
CEA Cadarache, Saint Paul Lez Durance, France

Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357.
A project using accelerator mass spectrometry (AMS) is underway at the ATLAS facility to measure the atom densities of transmutation products present in samples irradiated in the Advanced Test Reactor at INL. These atom densities will be used to infer effective actinide neutron capture cross-sections ranging from Thorium to Califorium isotopes in different neutron spectra relevant to advanced fuel cycles. This project will require the measurement of many samples with high precision and accuracy. The AMS technique at ATLAS is based on production of highly-charged positive ions in an ECRIS followed by injection into a linear accelerator. We use a picosecond laser to ablate the actinide material into the ion source. We expect that the laser ablation technique will have higher efficiency and lower chamber contamination than sputtering or oven evaporation thus reducing 'cross talk' between samples. The results of off-line ablation tests and first results of an accelerate beam generated by the laser coupled to the ECR will be discussed as well as the overall project schedule.

Slides FRXA03 [11.825 MB]

FRYA03

ECRIS Related Research and Development Work at JYFL and Some Future Prospects

ion, ion-source, photon, electron

203

H. A. Koivisto, J. Ärje, T. Kalvas, J.P.O. Komppula, R.J. Kronholm, J.P. Laulainen, O.A. Tarvainen, V. Toivanen
JYFL, Jyväskylä, Finland

Since the last ECR workshop the JYFL ion source group has focused on the plasma research, work on the ion beam formation and transport and development of metal ion beams. The plasma research can be divided into plasma breakdown processes, plasma and ion beam instabilities and afterglow processes. The afterglow and instability experiments will be presented elsewhere in these proceedings [1]. In addition, studies involving in the photoelectric induced electron emission and charge exchange reactions will be briefly discussed and the experiments concerning the resonance properties of empty and plasma loaded cavity will be presented. An improvement in ion beam transport of the JYFL K130 cyclotron facility was achieved as a result of the work performed on ion beam formation. This work will be described in more detailed elsewhere in these proceedings [2]. The MIVOC method and sputtering technique were further studied in order to produce intensive titanium ion beams. As a result, an intensive {50}Ti ion beam was successfully produced with the MIVOC method and interesting behavior regarding the sputtering was noticed.
[1] V. Skalyga et al. and O. Tarvainen et al.
[2] V. Toivanen et al.

Slides FRYA03 [4.159 MB]