ECRIS2012 - List of Keywords (ECRIS)

Paper	Title	Other Keywords	Page
TUXO02	An Experimental Study of ECRIS Plasma Stability and Oscillation of Beam Current	ECR, plasma, ion, ion-source	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	plasma, ion, ECR, ion-source	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]

TUYO03	Secondary-electron-enhanced Plasma as an Alternative to Double/Variable-frequency Heating in ECRIS	plasma, 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]

TUPP05	Charge-breeding at the Texas A&M University Cyclotron Institute	ion, injection, plasma, 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.

TUPP12	Design of Web-based Interface to RIKEN 28 GHz Super-conducting ECR Ion Source and the Future Plan	controls, EPICS, ion, operation	61
	A. Uchiyama Sokendai, Ibaraki, Japan K. Furukawa KEK, Ibaraki, Japan Y. Higurashi, M. Komiyama, T. Nakagawa, K. Ozeki RIKEN Nishina Center, Wako, Japan
	A new RIKEN 28 GHz superconducting ECR ion source (28 GHz-ECRIS) was constructed in 2009 in order to increase the intensity of Uranium ion beam for RIKEN RI beam factory project(RIBF). For effective and stable operation of the 28 GHz-ECRIS, its client system should have an user-friendly man-machine interface. The ECRIS control system was constructed with the Experimental Physics and Industrial Control System (EPICS) as well as RIBF control system. As a result, it was successful to provide the useful clients, such as the operation GUI panels, the XY chart application, and the data acquisition system in EPICS-based system. On the other hand, to keep beam quality from 28 GHz-ECRIS for a long beam service term, it should be possible to operate the ECRIS by members of ion source team at any time. In order to relieve concern in the overseas business trip of members of ion source team, we designed a real-time web-based client system using WebSocket, which is a new protocol presented by Internet Engineering Task Force (IETF). In this paper, we report the system and development status in detail. I. Fette and A. Melnikov. The WebSocket Protocol, IETF HyBi Working Group. 2011.

TUPP18	DECRIS-5 Ion Source for DC-110 Cyclotron Complex Results of the First Tests	ion, injection, ion-source, extraction	74
	A.A. Efremov, V. Bekhterev, S.L. Bogomolov, Yu.K. Kostyukhov, N. Lebedev, V.N. Loginov, Yu. Yazvitsky JINR, Dubna, Moscow Region, Russia V. Mironov KVI, Groningen, The Netherlands
	The project of the DC-110 cyclotron facility to provide applied research in the nanotechnologies (track pore membranes, surface modification of materials, etc.) has been designed by the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research (Dubna). The facility includes the isochronous cyclotron DC-110 for accelerating the intense Ar, Kr, Xe ion beams with 2.5 MeV/nucleon fixed energy. The cyclotron is equipped with system of axial injection and ECR ion source DECRIS-5, operating at the frequency of 18 GHz. The main parameters of DECRIS-5 ion source and results of the first tests are presented in this report.

WEXO02	Recent Developments and Electron Density Simulations at the ATOMKI 14.5 GHz ECRIS	electron, plasma, ion, simulation	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, plasma, extraction, ECR	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]

WEZO02	Design of new 18 GHz ECR for RIKEN RIBF	ion, plasma, ion-source, 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]

WEPP08	Emittance Measurements for U Ion Beams Produced from RIKEN 28 GHz SC-ECRIS	ion, emittance, brightness, heavy-ion	130
	K. Ozeki, Y. Higurashi, T. Nakagawa, J. Ohnishi RIKEN Nishina Center, Wako, Japan
	In order to investigate the ion optical parameters of the beam line of RIKEN 28 GHz SC-ECR ion source into the new heavy ion linac (RILAC II), we measured the emittance of the heavy ion beams form RIKEN 28 GHz SC-ECR ion source. In the test experiments, we observed that the emittance of the U³⁵⁺ beam was ~100 π·mm·mrad (4 rms emittance), which is smaller than the acceptance of the accelerator (~160 π·mm·mrad). The emittance with 28 GHz was almost same as that with 18 GHz and independent on the injected RF power (1~2 kW). The size of emittance increased with decreasing the charge state. We also measured the emittance of U and oxygen ions under the same condition. In this experiment we observed that the emittance of oxygen ions was always larger than the U ion beam for same M/q. In this contribution, we report the experimental results for emittance measurement of highly charged U, Xe and O ions from RIKEN 28 GHz SC-ECR ion source in detail.

WEPP15	Metal Ion Beam Production with Improved Evaporation Ovens	ion, operation, ion-source, plasma	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.

THXO01	Optimization of the New SC Magnetic Structure Design with a Hybrid Magnet	injection, solenoid, plasma, 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]

THXO03	Recent RIKEN 28 GHz SC-ECRIS Results	ion, ion-source, extraction, ECR	159
	Y. Higurashi, M. Fujimaki, H. Haba, O. Kamigaito, M. Kidera, M. Komiyama, J. Ohnishi, K. Ozeki RIKEN Nishina Center, Wako, Japan T. Aihara, M. Tamura, A. Uchiyama SHI Accelerator Service Ltd., Tokyo, Japan
	For increasing the beam intensity of highly charged heavy ions at RIKEN RIBF, we constructed new SC-ECR ion source. In the spring of 2011, we injected 28GHz microwave into the ion source and obtained first beam. Since then, we made several test experiments for increasing the beam intensity of highly charged Xe and U ion beam, and produced ~60 eμA of U³⁵⁺, ~90 eμA of U³³⁺ at the injected RF power of ~2 kW using sputtering method. In case of Xe²⁵⁺, 250 euA was obtained at RF power of 1.7 kW. Using sputtering method, we produced U³⁵⁺ ion beam longer than one month for the RIBF experiment without break. In the beginning of 2012, we installed additional GM-JT refrigerator to increase the cooling power at 4.2 K, then the total cooling power became higher than 9 W. Using it, we can use higher than 8 W of cooling power for heat load due to the absorbed X-rays. In this summer, we will install the new plasma chamber made of Al for increasing the cooling power. We will also use high temperature oven to increase the U vapor. In this contribution, we report the recent modification of the ion source and test experiments for production of U and Xe ion beam.
	Slides THXO03 [49.487 MB]

FRYA01	ECRISs at GANIL Today and Tomorrow	ion, target, ion-source, ECR	195
	P. Jardin, O. Bajeat, C. Barue, C. Canet, P. Delahaye, M. Dubois, M. Dupuis, J.L. Flambard, R. Frigot, C. Leboucher, P. Lehérissier, F. Lemagnen, L. Maunoury, O. Osmond, J. Piot, E.K. Traykov GANIL, Caen, France B.J.P. Gall IPHC, Strasbourg Cedex 2, France C. Peaucelle IN2P3 IPNL, Villeurbanne, France J. Rubert, T. Thuillier LPSC, Grenoble Cedex, France O. Tuske CEA/DSM/IRFU, France
	GANIL (Grand accélérateur National d'Ions Lourds) uses ECRIS for producing stable and radioactive ions since more than 20 years. 2 ECR4 type IS deliver intense multi-charged stable ion beams of gaseous and metallic elements to cyclotrons for post acceleration to energies up to 100 A·MeV. A full permanent magnet ECRIS is also used for producing multi-charged radioactive ion beams in the frame of SPIRAL 1 (Système de Production d'Ions radioactifs Accélérés en Ligne, part 1). For atomic physic experiment, a high performance ECRIS named GTS developed at CENG/ Grenoble (France) is currently used to deliver high intensity, high charge state and low energy ion beams. To extend the range of radioactive ion beams available at GANIL, two ISOL (Isotope Separator On Line) projects are underway (SPIRAL2 and SPIRAL1 upgrade). In the frame of these projects, radiation hard singly-charged ECRIS, Q/A=1/3 ECRIS, 2.45 GHz deuteron ECRIS and permanent magnet TISS (Target Ion Source System) using an ECRIS are in development in parallel. A review of the main uses, current developments and performances obtained or expected with ECRISs at GANIL will be presented.
	Slides FRYA01 [6.926 MB]

Paper

Title

Other Keywords

Page

TUXO02

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

ECR, plasma, ion, ion-source

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

plasma, ion, ECR, ion-source

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]

TUYO03

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

plasma, 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]

TUPP05

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

ion, injection, plasma, 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.

TUPP12

Design of Web-based Interface to RIKEN 28 GHz Super-conducting ECR Ion Source and the Future Plan

controls, EPICS, ion, operation

61

A. Uchiyama
Sokendai, Ibaraki, Japan
K. Furukawa
KEK, Ibaraki, Japan
Y. Higurashi, M. Komiyama, T. Nakagawa, K. Ozeki
RIKEN Nishina Center, Wako, Japan

A new RIKEN 28 GHz superconducting ECR ion source (28 GHz-ECRIS) was constructed in 2009 in order to increase the intensity of Uranium ion beam for RIKEN RI beam factory project(RIBF). For effective and stable operation of the 28 GHz-ECRIS, its client system should have an user-friendly man-machine interface. The ECRIS control system was constructed with the Experimental Physics and Industrial Control System (EPICS) as well as RIBF control system. As a result, it was successful to provide the useful clients, such as the operation GUI panels, the XY chart application, and the data acquisition system in EPICS-based system. On the other hand, to keep beam quality from 28 GHz-ECRIS for a long beam service term, it should be possible to operate the ECRIS by members of ion source team at any time. In order to relieve concern in the overseas business trip of members of ion source team, we designed a real-time web-based client system using WebSocket*, which is a new protocol presented by Internet Engineering Task Force (IETF). In this paper, we report the system and development status in detail.
* I. Fette and A. Melnikov. The WebSocket Protocol, IETF HyBi Working Group. 2011.

TUPP18

DECRIS-5 Ion Source for DC-110 Cyclotron Complex Results of the First Tests

ion, injection, ion-source, extraction

74

A.A. Efremov, V. Bekhterev, S.L. Bogomolov, Yu.K. Kostyukhov, N. Lebedev, V.N. Loginov, Yu. Yazvitsky
JINR, Dubna, Moscow Region, Russia
V. Mironov
KVI, Groningen, The Netherlands

The project of the DC-110 cyclotron facility to provide applied research in the nanotechnologies (track pore membranes, surface modification of materials, etc.) has been designed by the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research (Dubna). The facility includes the isochronous cyclotron DC-110 for accelerating the intense Ar, Kr, Xe ion beams with 2.5 MeV/nucleon fixed energy. The cyclotron is equipped with system of axial injection and ECR ion source DECRIS-5, operating at the frequency of 18 GHz. The main parameters of DECRIS-5 ion source and results of the first tests are presented in this report.

WEXO02

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

electron, plasma, ion, simulation

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, plasma, extraction, ECR

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]

WEZO02

Design of new 18 GHz ECR for RIKEN RIBF

ion, plasma, ion-source, 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]

WEPP08

Emittance Measurements for U Ion Beams Produced from RIKEN 28 GHz SC-ECRIS

ion, emittance, brightness, heavy-ion

130

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

In order to investigate the ion optical parameters of the beam line of RIKEN 28 GHz SC-ECR ion source into the new heavy ion linac (RILAC II), we measured the emittance of the heavy ion beams form RIKEN 28 GHz SC-ECR ion source. In the test experiments, we observed that the emittance of the U³⁵⁺ beam was ~100 π·mm·mrad (4 rms emittance), which is smaller than the acceptance of the accelerator (~160 π·mm·mrad). The emittance with 28 GHz was almost same as that with 18 GHz and independent on the injected RF power (1~2 kW). The size of emittance increased with decreasing the charge state. We also measured the emittance of U and oxygen ions under the same condition. In this experiment we observed that the emittance of oxygen ions was always larger than the U ion beam for same M/q. In this contribution, we report the experimental results for emittance measurement of highly charged U, Xe and O ions from RIKEN 28 GHz SC-ECR ion source in detail.

WEPP15

Metal Ion Beam Production with Improved Evaporation Ovens

ion, operation, ion-source, plasma

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.

THXO01

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

injection, solenoid, plasma, 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]

THXO03

Recent RIKEN 28 GHz SC-ECRIS Results

ion, ion-source, extraction, ECR

159

Y. Higurashi, M. Fujimaki, H. Haba, O. Kamigaito, M. Kidera, M. Komiyama, J. Ohnishi, K. Ozeki
RIKEN Nishina Center, Wako, Japan
T. Aihara, M. Tamura, A. Uchiyama
SHI Accelerator Service Ltd., Tokyo, Japan

For increasing the beam intensity of highly charged heavy ions at RIKEN RIBF, we constructed new SC-ECR ion source. In the spring of 2011, we injected 28GHz microwave into the ion source and obtained first beam. Since then, we made several test experiments for increasing the beam intensity of highly charged Xe and U ion beam, and produced ~60 eμA of U³⁵⁺, ~90 eμA of U³³⁺ at the injected RF power of ~2 kW using sputtering method. In case of Xe²⁵⁺, 250 euA was obtained at RF power of 1.7 kW. Using sputtering method, we produced U³⁵⁺ ion beam longer than one month for the RIBF experiment without break. In the beginning of 2012, we installed additional GM-JT refrigerator to increase the cooling power at 4.2 K, then the total cooling power became higher than 9 W. Using it, we can use higher than 8 W of cooling power for heat load due to the absorbed X-rays. In this summer, we will install the new plasma chamber made of Al for increasing the cooling power. We will also use high temperature oven to increase the U vapor. In this contribution, we report the recent modification of the ion source and test experiments for production of U and Xe ion beam.

Slides THXO03 [49.487 MB]

FRYA01

ECRISs at GANIL Today and Tomorrow

ion, target, ion-source, ECR

195

P. Jardin, O. Bajeat, C. Barue, C. Canet, P. Delahaye, M. Dubois, M. Dupuis, J.L. Flambard, R. Frigot, C. Leboucher, P. Lehérissier, F. Lemagnen, L. Maunoury, O. Osmond, J. Piot, E.K. Traykov
GANIL, Caen, France
B.J.P. Gall
IPHC, Strasbourg Cedex 2, France
C. Peaucelle
IN2P3 IPNL, Villeurbanne, France
J. Rubert, T. Thuillier
LPSC, Grenoble Cedex, France
O. Tuske
CEA/DSM/IRFU, France

GANIL (Grand accélérateur National d'Ions Lourds) uses ECRIS for producing stable and radioactive ions since more than 20 years. 2 ECR4 type IS deliver intense multi-charged stable ion beams of gaseous and metallic elements to cyclotrons for post acceleration to energies up to 100 A·MeV. A full permanent magnet ECRIS is also used for producing multi-charged radioactive ion beams in the frame of SPIRAL 1 (Système de Production d'Ions radioactifs Accélérés en Ligne, part 1). For atomic physic experiment, a high performance ECRIS named GTS developed at CENG/ Grenoble (France) is currently used to deliver high intensity, high charge state and low energy ion beams. To extend the range of radioactive ion beams available at GANIL, two ISOL (Isotope Separator On Line) projects are underway (SPIRAL2 and SPIRAL1 upgrade). In the frame of these projects, radiation hard singly-charged ECRIS, Q/A=1/3 ECRIS, 2.45 GHz deuteron ECRIS and permanent magnet TISS (Target Ion Source System) using an ECRIS are in development in parallel. A review of the main uses, current developments and performances obtained or expected with ECRISs at GANIL will be presented.

Slides FRYA01 [6.926 MB]