ECRIS2010 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
MOCOCK04	Measurement of the Sixty GHz ECR Ion Source using Megawatt Magnets - SEISM Magnetic Field Map	extraction, injection, ECR, ion-source	33
	M. Marie-Jeanne, J. Jacob, T. Lamy, L. Latrasse LPSC, Grenoble Cedex, France F. Debray, J. Matera, R. Pfister, C. Trophime GHMFL, Grenoble, France
	LPSC has developed a prototype of 60GHz Electron Cyclotron Resonance (ECR) Ion Source called SEISM. The first 60GHz magnetic structure is based on a cusp geometry, using resistive polyhelix coils designed in collaboration with the Intense Magnetic Fields National Laboratory (LNCMI). A dedicated test bench helices coils in their tanks, electrical, and water cooling environment was built to study the mechanics, thermal behaviour and magnetic field characteristics obtained at various current levels. During the last months, measurements were performed for several magnetic configurations, with up to 7000A applied on the injection/extraction coils set. The magnetic field achieved at 13000A is expected to allow 28GHz ECR condition. However, cavitation issues that appeared around 7000A are to be solved before carrying on with the tests. This contribution will recall some of the crucial steps in the prototype fabrication, and show preliminary results from the measurements at 7000A. Possible explanations for the discrepancies observed between the results and the simulation will be given.
	Slides MOCOCK04 [3.243 MB]

MOPOT002	Two-Chamber Configuration of the Bio-Nano ECRIS	ion, plasma, ECRIS, extraction	43
	T. Uchida, H. Minezaki, Y. Yoshida Toyo University, Kawagoe-shi, Saitama, Japan T. Asaji, K. Tanaka Tateyama Machine Co. Ltd., Toyama-shi, Japan S. Biri, R. Rácz ATOMKI, Debrecen, Hungary Y. Kato Osaka University, Graduate School of Engineering, Osaka, Japan A. Kitagawa, M. Muramatsu NIRS, Chiba-shi, Japan
	The Bio-Nano ECRIS was designed for new materials production on nano-scale [1]. Our main target is the endohedral fullerene, which have potential in medical care, biotechnology and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. There are several promising approaches to produce the endohedral fullerenes using an ECRIS. One of them is the ion-ion collision reaction of fullerenes and aliens ions to be encapsulated in the mixture plasma of them. Another way is the shooting of ion beam into a pre-prepared fullerene layer. In this study, the new device configuration of the Bio-Nano ECRIS is reported which allows the application of both methods. The plasma chamber is divided into two chambers by installing mesh electrodes. In the gas injection-side 1st chamber at 2.45 GHz plasmas (N₂, Ar, He, Fe,) are produced on the usual way. These ions then are extracted to the 2nd chamber where an evaporation boat for fullerene is installed. The fullerene neutrals can be ionized (using 10 GHz in the 2nd chamber) and are deposited on a large plasma electrode where they are continuously irradiated by the ions from the 1st chamber. The ions produced either in the 1st or 2nd chamber can be in-situ extracted and analyzed. The basic concept and the preliminary results using Ar gas and N₂ gas plasmas will be presented. [1] T. Uchida et al., Proc. ECRIS08, Chicago, USA, pp. 27-31 (2008)
	Poster MOPOT002 [6.248 MB]

TUPOT007	Preliminary Design of BLISI, an Off Resonance Microwave Proton Source	plasma, ion, extraction, proton	130
	S. Djekic, I. Bustinduy, D. Cortazar, D. Fernandez-Cañoto, H. Hassanzadegan, J.L. Munoz, D. de Cos ESS Bilbao, Bilbao, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain M.A. Carrera, J.H. Galipienzo AVS, Eibar, Gipuzkoa, Spain V. Etxebarria, J. Jugo, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain J. Feuchtwanger, I. Rueda ESS-Bilbao, Zamudio, Spain J. Lucas Elytt Energy, Madrid, Spain
	A new high current off resonance microwave H⁺ source is currently in the last stages of design at ESS-Bilbao, in collaboration with two external companies Elytt and AVS. The design is intended to be a high-stability, high-current ion source capable of delivering a 70 mA proton beam with a 70 keV energy at the end of the extraction. The plasma system designed by Elytt consists of a water-cooled plasma chamber that sits between two independently powered magnetic coils that generate the ECR magnetic field; in addition they can be moved independently to further shape the magnetic field in the chamber. A CPI 2.7 GHz klystron provides the microwave energy and a fully controlled microwave system to minimize reflected power and improve the source overall performance is also under construction. The extraction column designed by AVS will consist of a movable tetrode system designed for a maximum acceleration potential of 70 kV, the shape of the electrodes is at an earlier design stage at ESS-Bilbao. We will present the current layout of the source, simulations and schematics of the source.
	Poster TUPOT007 [3.954 MB]

TUPOT008	Performance of the LBNL AECR-U with a TWTA	plasma, ion, coupling, ion-source	133
	J.Y. Benitez, D. Leitner, C.M. Lyneis LBNL, Berkeley, California, USA M.K. Covo LLNL, Livermore, California, USA
	The Advanced Electron Cyclotron Resonance - Upgrade ion source (AECR-U) at the Lawrence Berkeley National Laboratory has successfully utilized double frequency microwave heating (14.3 GHz and 10.4 GHz) for several years [1]. Recently a traveling wave tube amplifier (TWTA), providing frequencies in the range of 10.75GHz-12.75GHz, was added as a secondary heating frequency, replacing the previous 10.4 GHz Klystron. The TWTA opens the possibility to explore a wide range of secondary frequencies and a study has been conducted to understand and optimize its coupling into the AECR-U. In particular, the reflected power dependence on heating frequency has been mapped out with and without the presence of plasma. A comparison is made to determine how the presence of plasma, confinement fields, and other source parameters affect the reflected power and if and how the amount of reflected power can be correlated to the source ion beam performance. [1] Z. Q. Xie and C. M. Lyneis, Rev. Sci. Instrum. 66 (1995).
	Poster TUPOT008 [0.213 MB]

TUPOT018	Sheath Formation of a Plasma Containing Multiply Charged Ions, Cold and Hot Electrons, and Emitted Electrons	electron, ion, plasma, ion-source	159
	H.J. You NFRI, Daejon, Republic of Korea
	A model of sheath formation was extended to a plasma containing multiply charged ions (MCIs), cold and hot electrons, and secondary electrons emitted either by MCIs or hot electrons. The present study was motivated by the fact that the secondary electron yields are strongly dependent on the charge state of the ions and on the incident energy of electrons. Therefore, the contributions of the secondary electron emissions on the sheath formation would be severe in ECRIS plasmas where the charge state of ions is high and highly energetic electrons exist. In the model, modification of the “Bohm criterion” was given; thereby the sheath potential drop and the critical emission condition were analyzed. The model calculations were made mainly on the effects of the emitted electrons on the variations of the sheath potential drop, the particle and heat flux to the wall, by which some explanations for the effect of secondary electrons in ECR ion sources are given.
	Poster TUPOT018 [0.259 MB]

WECOAK02	Some Considerations About Frequency Tuning Effect in ECRIS Plasmas	plasma, ion, electron, simulation	165
	D. Mascali, G. Castro, L. Celona, G. Ciavola, N. Gambino, S. Gammino, R. Miracoli, L. Neri INFN/LNS, Catania, Italy F. Maimone GSI, Darmstadt, Germany
	During the last years many experiments have demonstrated that slight variations in microwave frequency used to heat and sustain the plasma of ECRIS may strongly influence their performances (frequency tuning effect) both in terms of extracted current and mean charge state. Theoretical investigations revealed that this phenomenon can be correctly explained assuming that the plasma chamber works as a resonant cavity: standing waves are excited inside of it, and their spatial structure considerably changes even with slight variations of the pumping frequency. Therefore some particular modes present a higher electric field on the resonance surface, that is the only region in which the energy transfer from waves to electrons occurs. Experimental measurements carried out on microwave discharge plasmas at high density (up to 10¹¹ cm^-3) featured that even if the absorption of electromagnetic energy at the ECR surface is evident, the stochastic nature of the wave-electron interaction allows the wave to be reflected at the extraction flange, thus forming a standing wave. The model here proposed, and based on PIC and MonteCarlo collisional simulations, puts in evidence that the frequency tuning effect in ECRIS has a global influence on plasma properties: it strongly affects both ion and electron dynamics. Electron heating, electron density distribution, ion formation and acceleration at resonance surface, beam formation are determined by the particular mode excited inside the cavity. This means that the frequency tuning will be an important tool for future ECRIS for the optimization of the beam quality (emittance, etc.).
	Slides WECOAK02 [4.765 MB]

WECOAK05	Maximum Bremsstrahlung Energy Versus Different Heating Limits	electron, plasma, ECRIS, photon	175
	H. A. Koivisto, V.P. Aho, P. Jones, P. Peura, J.H. Sarén, O.A. Tarvainen, V.A. Toivanen JYFL, Jyväskylä, Finland
	A comprehensive set of bremsstrahlung measurements have been performed at JYFL (University of Jyväskylä, Department of Physics) in order to understand the parameters affecting the time evolution of electron energy. In order to extend the understanding of electron heating, a new set of measurements with the JYFL 6.4 GHz ECRIS have been initiated to further study the parameters affecting the maximum bremsstrahlung energy. In the measurements the effect of magnetic field gradient, microwave power, plasma size and gas pressure were studied. In the analysis, main focus will be given to compare the results with different theoretical electron heating limits.
	Slides WECOAK05 [0.739 MB]

Paper

Title

Other Keywords

Page

MOCOCK04

Measurement of the Sixty GHz ECR Ion Source using Megawatt Magnets - SEISM Magnetic Field Map

extraction, injection, ECR, ion-source

33

M. Marie-Jeanne, J. Jacob, T. Lamy, L. Latrasse
LPSC, Grenoble Cedex, France
F. Debray, J. Matera, R. Pfister, C. Trophime
GHMFL, Grenoble, France

LPSC has developed a prototype of 60GHz Electron Cyclotron Resonance (ECR) Ion Source called SEISM. The first 60GHz magnetic structure is based on a cusp geometry, using resistive polyhelix coils designed in collaboration with the Intense Magnetic Fields National Laboratory (LNCMI). A dedicated test bench helices coils in their tanks, electrical, and water cooling environment was built to study the mechanics, thermal behaviour and magnetic field characteristics obtained at various current levels. During the last months, measurements were performed for several magnetic configurations, with up to 7000A applied on the injection/extraction coils set. The magnetic field achieved at 13000A is expected to allow 28GHz ECR condition. However, cavitation issues that appeared around 7000A are to be solved before carrying on with the tests. This contribution will recall some of the crucial steps in the prototype fabrication, and show preliminary results from the measurements at 7000A. Possible explanations for the discrepancies observed between the results and the simulation will be given.

Slides MOCOCK04 [3.243 MB]

MOPOT002

Two-Chamber Configuration of the Bio-Nano ECRIS

ion, plasma, ECRIS, extraction

43

T. Uchida, H. Minezaki, Y. Yoshida
Toyo University, Kawagoe-shi, Saitama, Japan
T. Asaji, K. Tanaka
Tateyama Machine Co. Ltd., Toyama-shi, Japan
S. Biri, R. Rácz
ATOMKI, Debrecen, Hungary
Y. Kato
Osaka University, Graduate School of Engineering, Osaka, Japan
A. Kitagawa, M. Muramatsu
NIRS, Chiba-shi, Japan

The Bio-Nano ECRIS was designed for new materials production on nano-scale [1]. Our main target is the endohedral fullerene, which have potential in medical care, biotechnology and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. There are several promising approaches to produce the endohedral fullerenes using an ECRIS. One of them is the ion-ion collision reaction of fullerenes and aliens ions to be encapsulated in the mixture plasma of them. Another way is the shooting of ion beam into a pre-prepared fullerene layer. In this study, the new device configuration of the Bio-Nano ECRIS is reported which allows the application of both methods. The plasma chamber is divided into two chambers by installing mesh electrodes. In the gas injection-side 1st chamber at 2.45 GHz plasmas (N₂, Ar, He, Fe,) are produced on the usual way. These ions then are extracted to the 2nd chamber where an evaporation boat for fullerene is installed. The fullerene neutrals can be ionized (using 10 GHz in the 2nd chamber) and are deposited on a large plasma electrode where they are continuously irradiated by the ions from the 1st chamber. The ions produced either in the 1st or 2nd chamber can be in-situ extracted and analyzed. The basic concept and the preliminary results using Ar gas and N₂ gas plasmas will be presented.
[1] T. Uchida et al., Proc. ECRIS08, Chicago, USA, pp. 27-31 (2008)

Poster MOPOT002 [6.248 MB]

TUPOT007

Preliminary Design of BLISI, an Off Resonance Microwave Proton Source

plasma, ion, extraction, proton

130

S. Djekic, I. Bustinduy, D. Cortazar, D. Fernandez-Cañoto, H. Hassanzadegan, J.L. Munoz, D. de Cos
ESS Bilbao, Bilbao, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
M.A. Carrera, J.H. Galipienzo
AVS, Eibar, Gipuzkoa, Spain
V. Etxebarria, J. Jugo, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
J. Feuchtwanger, I. Rueda
ESS-Bilbao, Zamudio, Spain
J. Lucas
Elytt Energy, Madrid, Spain

A new high current off resonance microwave H⁺ source is currently in the last stages of design at ESS-Bilbao, in collaboration with two external companies Elytt and AVS. The design is intended to be a high-stability, high-current ion source capable of delivering a 70 mA proton beam with a 70 keV energy at the end of the extraction. The plasma system designed by Elytt consists of a water-cooled plasma chamber that sits between two independently powered magnetic coils that generate the ECR magnetic field; in addition they can be moved independently to further shape the magnetic field in the chamber. A CPI 2.7 GHz klystron provides the microwave energy and a fully controlled microwave system to minimize reflected power and improve the source overall performance is also under construction. The extraction column designed by AVS will consist of a movable tetrode system designed for a maximum acceleration potential of 70 kV, the shape of the electrodes is at an earlier design stage at ESS-Bilbao. We will present the current layout of the source, simulations and schematics of the source.

Poster TUPOT007 [3.954 MB]

TUPOT008

Performance of the LBNL AECR-U with a TWTA

plasma, ion, coupling, ion-source

133

J.Y. Benitez, D. Leitner, C.M. Lyneis
LBNL, Berkeley, California, USA
M.K. Covo
LLNL, Livermore, California, USA

The Advanced Electron Cyclotron Resonance - Upgrade ion source (AECR-U) at the Lawrence Berkeley National Laboratory has successfully utilized double frequency microwave heating (14.3 GHz and 10.4 GHz) for several years [1]. Recently a traveling wave tube amplifier (TWTA), providing frequencies in the range of 10.75GHz-12.75GHz, was added as a secondary heating frequency, replacing the previous 10.4 GHz Klystron. The TWTA opens the possibility to explore a wide range of secondary frequencies and a study has been conducted to understand and optimize its coupling into the AECR-U. In particular, the reflected power dependence on heating frequency has been mapped out with and without the presence of plasma. A comparison is made to determine how the presence of plasma, confinement fields, and other source parameters affect the reflected power and if and how the amount of reflected power can be correlated to the source ion beam performance.
[1] Z. Q. Xie and C. M. Lyneis, Rev. Sci. Instrum. 66 (1995).

Poster TUPOT008 [0.213 MB]

TUPOT018

Sheath Formation of a Plasma Containing Multiply Charged Ions, Cold and Hot Electrons, and Emitted Electrons

electron, ion, plasma, ion-source

159

H.J. You
NFRI, Daejon, Republic of Korea

A model of sheath formation was extended to a plasma containing multiply charged ions (MCIs), cold and hot electrons, and secondary electrons emitted either by MCIs or hot electrons. The present study was motivated by the fact that the secondary electron yields are strongly dependent on the charge state of the ions and on the incident energy of electrons. Therefore, the contributions of the secondary electron emissions on the sheath formation would be severe in ECRIS plasmas where the charge state of ions is high and highly energetic electrons exist. In the model, modification of the “Bohm criterion” was given; thereby the sheath potential drop and the critical emission condition were analyzed. The model calculations were made mainly on the effects of the emitted electrons on the variations of the sheath potential drop, the particle and heat flux to the wall, by which some explanations for the effect of secondary electrons in ECR ion sources are given.

Poster TUPOT018 [0.259 MB]

WECOAK02

Some Considerations About Frequency Tuning Effect in ECRIS Plasmas

plasma, ion, electron, simulation

165

D. Mascali, G. Castro, L. Celona, G. Ciavola, N. Gambino, S. Gammino, R. Miracoli, L. Neri
INFN/LNS, Catania, Italy
F. Maimone
GSI, Darmstadt, Germany

During the last years many experiments have demonstrated that slight variations in microwave frequency used to heat and sustain the plasma of ECRIS may strongly influence their performances (frequency tuning effect) both in terms of extracted current and mean charge state. Theoretical investigations revealed that this phenomenon can be correctly explained assuming that the plasma chamber works as a resonant cavity: standing waves are excited inside of it, and their spatial structure considerably changes even with slight variations of the pumping frequency. Therefore some particular modes present a higher electric field on the resonance surface, that is the only region in which the energy transfer from waves to electrons occurs. Experimental measurements carried out on microwave discharge plasmas at high density (up to 10¹¹ cm^-3) featured that even if the absorption of electromagnetic energy at the ECR surface is evident, the stochastic nature of the wave-electron interaction allows the wave to be reflected at the extraction flange, thus forming a standing wave. The model here proposed, and based on PIC and MonteCarlo collisional simulations, puts in evidence that the frequency tuning effect in ECRIS has a global influence on plasma properties: it strongly affects both ion and electron dynamics. Electron heating, electron density distribution, ion formation and acceleration at resonance surface, beam formation are determined by the particular mode excited inside the cavity. This means that the frequency tuning will be an important tool for future ECRIS for the optimization of the beam quality (emittance, etc.).

Slides WECOAK02 [4.765 MB]

WECOAK05

Maximum Bremsstrahlung Energy Versus Different Heating Limits

electron, plasma, ECRIS, photon

175

H. A. Koivisto, V.P. Aho, P. Jones, P. Peura, J.H. Sarén, O.A. Tarvainen, V.A. Toivanen
JYFL, Jyväskylä, Finland

A comprehensive set of bremsstrahlung measurements have been performed at JYFL (University of Jyväskylä, Department of Physics) in order to understand the parameters affecting the time evolution of electron energy. In order to extend the understanding of electron heating, a new set of measurements with the JYFL 6.4 GHz ECRIS have been initiated to further study the parameters affecting the maximum bremsstrahlung energy. In the measurements the effect of magnetic field gradient, microwave power, plasma size and gas pressure were studied. In the analysis, main focus will be given to compare the results with different theoretical electron heating limits.

Slides WECOAK05 [0.739 MB]