Cyclotrons2013 - Classification: Cyclotron Subsystems / Ion Sources, Injection

Paper

Title

Page

High Intensity Operation for Heavy Ion Cyclotron of Highly Charged ECR Ion Sources

125

L.T. Sun
IMP, Lanzhou, People's Republic of China

Modern advanced ECR ion source can provide stable and reliable high charge state ion beams for the routine operation of a cyclotron, which has made it irreplaceable, particularly with regard to the performance and efficiency that a cyclotron complex could achieve with the ion source. The 3rd generation ECR ion sources that can produce higher charge state and more intense ion beams have been developed and put into cyclotron operation since early 21st century. They have provided the privilege for the cyclotron performance improvement that has never been met before, especially in term of the delivered beam intensity and energy, which has greatly promoted the experimental research in nuclear physics. This paper will have a brief review about the development of modern high performance high charge state ECR ion sources. Typical advanced high charge state ECR ion sources with fully superconducting magnet, such as SERSE, VENUS, SECRAL, SuSI and RIKEN SC-ECRIS will be presented, and their high intensity operation status for cyclotrons will be introduced as well.

Slides TU1PB01 [20.645 MB]

TU1PB02

Electron Cyclotron Resonance Source Development

130

T. Thuillier
LBNL, Berkeley, California, USA

Trends in ECR ion source development and perspectives for performance improvement.

Slides TU1PB02 [8.635 MB]

TU1PB03

PIC Simulations of Ion Dynamics in ECR Ion Sources

134

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 of ions. The basic features of the numerical model are given elsewhere*. Electron temperature is a free parameter and we found that its value should be about 1 keV to reproduce the experimentally observed performance of our 14 GHz ECR source. We assume that a pre-sheath is located outside the ECR zone, in which ion acceleration toward the walls occurs. Electric fields inside the ECR zone are assumed to be zero. The ion production is modelled assuming 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. With these assumptions, we are able to reproduce the main features of ECRIS performance, such as saturation and decrease of highest charge state currents with increasing gas pressure, as well as reaction to an increase of injected RF power. Study of the source response to variations of the source parameters is possible.
*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 TU1PB03 [18.160 MB]

TU1PB04

Status of the RIKEN 28-GHz SC-ECRIS

139

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

Since we obtained first beam from RIKEN 28GHz SC-ECRIS in 2009, we tried to increase the beam intensity using various methods. Recently, we observed that the use of Al chamber strongly enhanced the beam intensity of highly charged U ion beam. Using this method, we obtained ~180e μA of U³⁵⁺ and ~230e μA of U³³⁺ at the injected RF power of ~3kW with sputtering method. Advantage of this method is that we can insert the large amount of material into the plasma chamber, therefore, we can produce the beam for long term without break. Actually, we already produced intense U beams for the RIBF experiments longer than month without break. For the long term operation, we observed that the consumption rate of the U metal was ~4mg/h. In this spring, we also produced U beam with high temperature oven and two frequencies injection. In these test experiments, we observed that the beam intensity of highly charged U ions is strongly enhanced. In this contribution, we report the various results of the test experiments for production of highly charged U ion beam. We also report the experience of the long term production of the U ion beam for RIKEN RIBF experiments.

Slides TU1PB04 [6.949 MB]

TUPPT013

Simulation of Sufficient Spindle Cusp Magnetic Field for 28 GHz ECRIS

180

M.H. Rashid, A. Chakrabarti
VECC, Kolkata, India

A cusp magnetic field (CMF) configuration is proposed for achieving more plasma confinement. It is an improved version of CMF compared to the classical one used earlier to design arbitrarily ECR ion source (ECRIS) of low frequency. The CMF has been reconfigured here adopting a simple, novel and cost-effective technique to shrink the loss area and to achieve denser plasma than in traditional ECRIS. The strength of the electron (plasma) confinement is demonstrated through electron simulations. It consists of a mid-iron disk, two end-plugs and a pair of superconducting magnet coils cooled by cryo-coolers. It is designed for high-B mode operation of the cusp ECRIS of as high as 28 GHz RF frequency for producing an intense beam of highly charged heavy ions. The electric current in the coil at the extraction end can be manipulated to optimize the operation to achieve high extracted beam current of highly charged ions.

TUPPT014

Characterization of the Versatile Ion Source (VIS) for the Production of Monocharged Light Ion Beams

183

L. Celona, L. Calabretta, G. Castro, G. Ciavola, S. Gammino, D. Mascali, L. Neri, G. Torrisi
INFN/LNS, Catania, Italy
G. Castro
Universita Degli Studi Di Catania, Catania, Italy
F. Di Bartolo
INFN & Messina University, S. Agata, Messina, Italy

Funding: The support of the 5th National Committee of INFN is gratefully acknowledged.
The Versatile Ion Source (VIS) is an off-resonance Microwave Discharge Ion Source which produces a slightly overdense plasma at 2.45 GHz of pumping frequency. In the measurements carried out at INFN-LNS in the last two years, VIS was able to produce more than 50 mA of proton beams and He⁺ beams at 65 kV, while for H²⁺ a current of 15 mA was obtained. The know-how obtained with the VIS source has been useful for the design of the proton source of the European Spallation Source, to be built in Lund, Sweden, and it will be used also for other facilities. In particular, the design modifications of the VIS source under study at INFN-LNS, in order to use the new source as the injector of H²⁺ at the ISODAR facility, will be also presented.

TUPPT015

A Center Region Upgrade of the LBNL 88-Inch Cyclotron

186

K. Yoshiki Franzen, J.Y. Benitez, M.K. Covo, A. Hodgkinson, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, M.M. Strohmeier, D.S. Todd
LBNL, Berkeley, California, USA
D. Leitner
NSCL, East Lansing, Michigan, USA

This paper describes the design and results of an upgraded cyclotron center region in which a mirror field type inflector was replaced by a spiral inflector. The main goals of the design were a) to facilitate injection at higher energies in order to improve transmission efficiency and b) to reduce down-time due to the need of replacing mirror inflector wires which rapidly break when exposed to high beam currents. The design was based on a detailed model of the spiral inflector and matching center region electrodes using AMaze, a 3D finite element suite of codes. Tests showed promising results indicating that the 88-Inch cyclotron will be able to provide a 2.0 pμA beam of 250 MeV 48Ca ions.

TUPPT016

Developments of Ion Source Complex for Highly Intense Beam at RCNP

189

T. Yorita, M. Fukuda, K. Hatanaka, K. Kamakura, S. Morinobu, A. Tamii, H. Ueda, Y. Yasuda
RCNP, Osaka, Japan

Several developments of Ion Source Complex at RCNP has been carried for the purpose of increasing beam intensity. For an 18 GHz superconducting ECRIS, studies for its beam extraction and transportation have been done. The parameters of extraction systems and electrostatic lens are optimized taking account with magnetic field leakage from AVF Cyclotron. HIP-ECR the 2.45GHz permanent magnet ECR has also been developed for highly intense proton beam.

TUPPT018

Critical Analysis of Negative Hydrogen Ion Sources for Cyclotrons

192

S. Korenev
Siemens Medical Solutions Molecular Imaging, Knoxville, TN, USA

The ion sources for cyclotrons based on negative hydrogen ions found applications as basic injectors for cyclotrons. The main important questions of negative hydrogen ion sources are following: i) method of production for negative hydrogen ions, ii) the extraction of ions and iii) separation of negative ions from electrons. Among of ion internal and external ion sources the common question is efficiency for production of negative hydrogen ions and increasing of kinetic energy of these ions. The critical analysis of different ions sources (PIG, Multicusps, etc.) is given. The comparison of these ion sources regarding applications for industrial cyclotrons for production of medical isotopes is presented in the paper.

Poster TUPPT018 [0.231 MB]

TUPPT019

Development Study of Penning Ion Source for Compact 9 MeV Cyclotron

195

Y.H. Yeon, J.-S. Chai, T.V. Cong, Kh.M. Gad, M. Ghergherehchi, S.Y. Jung, H.S. Kim, H.W. Kim, S.H. Kim, S.H. Lee, Y.S. Lee, X.J. Mu, S.Y. Oh, S. Shin
SKKU, Suwon, Republic of Korea

Funding: This research was supported by WCU (World Class University) program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (R31-2008-10029).
Penning Ion Gauge(PIG) have been used in internal source for cyclotron. PIG source for internal source of 9 MeV cyclotron produces H⁻ ion. This source consists of cold cathode which discharges electrons for producing H⁻ ion and anode for making plasma wall. Cold cathode material tantalum was used for emitting electrons and tungsten copper alloy was used for anode. The size of PIG source is related to size of cyclotron magnet. Optimization of cathode and anode location and sizing were needed for simplifying this source for reducing the size of compact cyclotron. Transportation of electrons and number of secondary electrons has been calculated by CST particle studio. Motion of H2 gas has been calculated by ANSYS. Calculation of PIG source in 9 MeV cyclotron has been performed by using various chimneys with different size of expansion gap between the plasma boundary and the chimney wall. In this paper design process and experiment result is reported.

TUPPT022

A 20 mA H⁻ Ion Source with Accel-Accel-Decel Extraction System at TRIUMF

198

K. Jayamanna, I. Aguilar, I.V. Bylinskii, G. Cojocaru, R.L. Dube, R.K. Laplante, W. L. Louie, M. Lovera, M. Minato, M. Mouat, S. Saminathan, T.M. Tateyama, E. Tikhomolov
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

During the last three decades, TRIUMF has developed H⁻ cusp ion sources for the 500 MeV, TR30, TR13 cyclotrons, as well as many other machines. These ion sources can be categorized as high current versions, producing up to 20mA of CW H⁻ beam within a normalized emittance (4RMS) of 0.6 π-mm-mrad. A new accel-accel-decel extraction system is being developed in order to run the source at optimum source extraction voltage for a large range of beam energies with minimal impact on beam properties. With this extraction system, beam energy can be as low as ~1keV and as high as 60keV while source extraction voltage can be at its optimum within 90kV. The source performances, as well as relevant emittance measurements, are discussed.

Paper	Title	Page
TU1PB01	High Intensity Operation for Heavy Ion Cyclotron of Highly Charged ECR Ion Sources	125
	L.T. Sun IMP, Lanzhou, People's Republic of China
	Modern advanced ECR ion source can provide stable and reliable high charge state ion beams for the routine operation of a cyclotron, which has made it irreplaceable, particularly with regard to the performance and efficiency that a cyclotron complex could achieve with the ion source. The 3rd generation ECR ion sources that can produce higher charge state and more intense ion beams have been developed and put into cyclotron operation since early 21st century. They have provided the privilege for the cyclotron performance improvement that has never been met before, especially in term of the delivered beam intensity and energy, which has greatly promoted the experimental research in nuclear physics. This paper will have a brief review about the development of modern high performance high charge state ECR ion sources. Typical advanced high charge state ECR ion sources with fully superconducting magnet, such as SERSE, VENUS, SECRAL, SuSI and RIKEN SC-ECRIS will be presented, and their high intensity operation status for cyclotrons will be introduced as well.
	Slides TU1PB01 [20.645 MB]

TU1PB02	Electron Cyclotron Resonance Source Development	130
	T. Thuillier LBNL, Berkeley, California, USA
	Trends in ECR ion source development and perspectives for performance improvement.
	Slides TU1PB02 [8.635 MB]

TU1PB03	PIC Simulations of Ion Dynamics in ECR Ion Sources	134
	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 of ions. The basic features of the numerical model are given elsewhere. Electron temperature is a free parameter and we found that its value should be about 1 keV to reproduce the experimentally observed performance of our 14 GHz ECR source. We assume that a pre-sheath is located outside the ECR zone, in which ion acceleration toward the walls occurs. Electric fields inside the ECR zone are assumed to be zero. The ion production is modelled assuming 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. With these assumptions, we are able to reproduce the main features of ECRIS performance, such as saturation and decrease of highest charge state currents with increasing gas pressure, as well as reaction to an increase of injected RF power. Study of the source response to variations of the source parameters is possible. 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 TU1PB03 [18.160 MB]

TU1PB04	Status of the RIKEN 28-GHz SC-ECRIS	139
	Y. Higurashi, M. Kidera, T. Nakagawa, J. Ohnishi, K. Ozeki RIKEN Nishina Center, Wako, Japan
	Since we obtained first beam from RIKEN 28GHz SC-ECRIS in 2009, we tried to increase the beam intensity using various methods. Recently, we observed that the use of Al chamber strongly enhanced the beam intensity of highly charged U ion beam. Using this method, we obtained ~180e μA of U³⁵⁺ and ~230e μA of U³³⁺ at the injected RF power of ~3kW with sputtering method. Advantage of this method is that we can insert the large amount of material into the plasma chamber, therefore, we can produce the beam for long term without break. Actually, we already produced intense U beams for the RIBF experiments longer than month without break. For the long term operation, we observed that the consumption rate of the U metal was ~4mg/h. In this spring, we also produced U beam with high temperature oven and two frequencies injection. In these test experiments, we observed that the beam intensity of highly charged U ions is strongly enhanced. In this contribution, we report the various results of the test experiments for production of highly charged U ion beam. We also report the experience of the long term production of the U ion beam for RIKEN RIBF experiments.
	Slides TU1PB04 [6.949 MB]

TUPPT013	Simulation of Sufficient Spindle Cusp Magnetic Field for 28 GHz ECRIS	180
	M.H. Rashid, A. Chakrabarti VECC, Kolkata, India
	A cusp magnetic field (CMF) configuration is proposed for achieving more plasma confinement. It is an improved version of CMF compared to the classical one used earlier to design arbitrarily ECR ion source (ECRIS) of low frequency. The CMF has been reconfigured here adopting a simple, novel and cost-effective technique to shrink the loss area and to achieve denser plasma than in traditional ECRIS. The strength of the electron (plasma) confinement is demonstrated through electron simulations. It consists of a mid-iron disk, two end-plugs and a pair of superconducting magnet coils cooled by cryo-coolers. It is designed for high-B mode operation of the cusp ECRIS of as high as 28 GHz RF frequency for producing an intense beam of highly charged heavy ions. The electric current in the coil at the extraction end can be manipulated to optimize the operation to achieve high extracted beam current of highly charged ions.

TUPPT014	Characterization of the Versatile Ion Source (VIS) for the Production of Monocharged Light Ion Beams	183
	L. Celona, L. Calabretta, G. Castro, G. Ciavola, S. Gammino, D. Mascali, L. Neri, G. Torrisi INFN/LNS, Catania, Italy G. Castro Universita Degli Studi Di Catania, Catania, Italy F. Di Bartolo INFN & Messina University, S. Agata, Messina, Italy
	Funding: The support of the 5th National Committee of INFN is gratefully acknowledged. The Versatile Ion Source (VIS) is an off-resonance Microwave Discharge Ion Source which produces a slightly overdense plasma at 2.45 GHz of pumping frequency. In the measurements carried out at INFN-LNS in the last two years, VIS was able to produce more than 50 mA of proton beams and He⁺ beams at 65 kV, while for H²⁺ a current of 15 mA was obtained. The know-how obtained with the VIS source has been useful for the design of the proton source of the European Spallation Source, to be built in Lund, Sweden, and it will be used also for other facilities. In particular, the design modifications of the VIS source under study at INFN-LNS, in order to use the new source as the injector of H²⁺ at the ISODAR facility, will be also presented.

TUPPT015	A Center Region Upgrade of the LBNL 88-Inch Cyclotron	186
	K. Yoshiki Franzen, J.Y. Benitez, M.K. Covo, A. Hodgkinson, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, M.M. Strohmeier, D.S. Todd LBNL, Berkeley, California, USA D. Leitner NSCL, East Lansing, Michigan, USA
	This paper describes the design and results of an upgraded cyclotron center region in which a mirror field type inflector was replaced by a spiral inflector. The main goals of the design were a) to facilitate injection at higher energies in order to improve transmission efficiency and b) to reduce down-time due to the need of replacing mirror inflector wires which rapidly break when exposed to high beam currents. The design was based on a detailed model of the spiral inflector and matching center region electrodes using AMaze, a 3D finite element suite of codes. Tests showed promising results indicating that the 88-Inch cyclotron will be able to provide a 2.0 pμA beam of 250 MeV 48Ca ions.

TUPPT016	Developments of Ion Source Complex for Highly Intense Beam at RCNP	189
	T. Yorita, M. Fukuda, K. Hatanaka, K. Kamakura, S. Morinobu, A. Tamii, H. Ueda, Y. Yasuda RCNP, Osaka, Japan
	Several developments of Ion Source Complex at RCNP has been carried for the purpose of increasing beam intensity. For an 18 GHz superconducting ECRIS, studies for its beam extraction and transportation have been done. The parameters of extraction systems and electrostatic lens are optimized taking account with magnetic field leakage from AVF Cyclotron. HIP-ECR the 2.45GHz permanent magnet ECR has also been developed for highly intense proton beam.

TUPPT018	Critical Analysis of Negative Hydrogen Ion Sources for Cyclotrons	192
	S. Korenev Siemens Medical Solutions Molecular Imaging, Knoxville, TN, USA
	The ion sources for cyclotrons based on negative hydrogen ions found applications as basic injectors for cyclotrons. The main important questions of negative hydrogen ion sources are following: i) method of production for negative hydrogen ions, ii) the extraction of ions and iii) separation of negative ions from electrons. Among of ion internal and external ion sources the common question is efficiency for production of negative hydrogen ions and increasing of kinetic energy of these ions. The critical analysis of different ions sources (PIG, Multicusps, etc.) is given. The comparison of these ion sources regarding applications for industrial cyclotrons for production of medical isotopes is presented in the paper.
	Poster TUPPT018 [0.231 MB]

TUPPT019	Development Study of Penning Ion Source for Compact 9 MeV Cyclotron	195
	Y.H. Yeon, J.-S. Chai, T.V. Cong, Kh.M. Gad, M. Ghergherehchi, S.Y. Jung, H.S. Kim, H.W. Kim, S.H. Kim, S.H. Lee, Y.S. Lee, X.J. Mu, S.Y. Oh, S. Shin SKKU, Suwon, Republic of Korea
	Funding: This research was supported by WCU (World Class University) program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (R31-2008-10029). Penning Ion Gauge(PIG) have been used in internal source for cyclotron. PIG source for internal source of 9 MeV cyclotron produces H⁻ ion. This source consists of cold cathode which discharges electrons for producing H⁻ ion and anode for making plasma wall. Cold cathode material tantalum was used for emitting electrons and tungsten copper alloy was used for anode. The size of PIG source is related to size of cyclotron magnet. Optimization of cathode and anode location and sizing were needed for simplifying this source for reducing the size of compact cyclotron. Transportation of electrons and number of secondary electrons has been calculated by CST particle studio. Motion of H2 gas has been calculated by ANSYS. Calculation of PIG source in 9 MeV cyclotron has been performed by using various chimneys with different size of expansion gap between the plasma boundary and the chimney wall. In this paper design process and experiment result is reported.

TUPPT022	A 20 mA H⁻ Ion Source with Accel-Accel-Decel Extraction System at TRIUMF	198
	K. Jayamanna, I. Aguilar, I.V. Bylinskii, G. Cojocaru, R.L. Dube, R.K. Laplante, W. L. Louie, M. Lovera, M. Minato, M. Mouat, S. Saminathan, T.M. Tateyama, E. Tikhomolov TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	During the last three decades, TRIUMF has developed H⁻ cusp ion sources for the 500 MeV, TR30, TR13 cyclotrons, as well as many other machines. These ion sources can be categorized as high current versions, producing up to 20mA of CW H⁻ beam within a normalized emittance (4RMS) of 0.6 π-mm-mrad. A new accel-accel-decel extraction system is being developed in order to run the source at optimum source extraction voltage for a large range of beam energies with minimal impact on beam properties. With this extraction system, beam energy can be as low as ~1keV and as high as 60keV while source extraction voltage can be at its optimum within 90kV. The source performances, as well as relevant emittance measurements, are discussed.