Cyclotrons2013 - List of Keywords (plasma)

Paper	Title	Other Keywords	Page
TU1PB02	Electron Cyclotron Resonance Source Development	ion, ECRIS, ECR, ion-source	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	ion, extraction, ECR, ECRIS	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]

TUPPT013	Simulation of Sufficient Spindle Cusp Magnetic Field for 28 GHz ECRIS	ECRIS, ion, ECR, electron	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	ion, electron, proton, ion-source	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.

TUPPT016	Developments of Ion Source Complex for Highly Intense Beam at RCNP	extraction, ion, ECR, emittance	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	ion, ion-source, cyclotron, electron	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	ion, electron, cathode, ion-source	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.

WE2PB02	Vlasov Equation Approach to Space Charge Effects in Isochronous Machines	space-charge, simulation, cyclotron, betatron	310
	A.J. Cerfon, O. Bühler, J.V. Guadagni Courant Institute of Mathematical Sciences, New York University, New York, USA J.P. Freidberg, F.I. Parra Diaz MIT/PSFC, Cambridge, Massachusetts, USA
	Starting from the collisionless Vlasov equation, we derive two simple coupled two-dimensional fluid equations describing the radial-longitudinal beam vortex motion associated with space charge effects in isochronous cyclotrons. These equations show that the vortex motion can be intuitively understood as the nonlinear advection of the beam by the ExB velocity field, where E is the electric field due to the space charge and B is the applied magnetic field. This explains why elongated beams develop spiral halos while round beams are always stable. Solving the coupled equations numerically, we find good agreement between our model and 3-D Particle-In-Cell OPAL simulations. J.J. Yang, A.Adelmann, M. Humbel, M. Seidel, and T.J. Zhang, Physical Review Special Topics Accelerators and Beams 13, 062401 (2010)
	Slides WE2PB02 [1.166 MB]

WE3PB01	Experimental Study of Resonance Crossing with a Paul Trap	resonance, emittance, simulation, ion	409
	H. Sugimoto KEK, Ibaraki, Japan
	The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands as in cyclotrons and FFAGs.
	Slides WE3PB01 [9.757 MB]

TH1PB04	Fabrication of Hydrophobic Surfaces from Hydrophilic BeO by Alpha-Irradiation-Induced Nuclear Transmutation	controls, radiation, cyclotron, target	443
	E.J. Lee, M.G. Hur, J.H. Park KAERI, Daejon, Republic of Korea Y.B. Kong, Y.D. Park, J.M. Son, S.D. Yang Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongup-si, Jeollabuk-do, Republic of Korea
	Hydrophobic surfaces were simply fabricated by irradiating hydrophilic BeO surfaces with an alpha particle beam from a cyclotron. In this research, BeO disks were irradiated under conditions of ~25 MeV in alpha particle energy and ~1 μA in beam current with different irradiation time. After the alpha irradiation, the changes in the morphology and chemical composition of BeO surfaces were analyzed using a field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The wetting property of alpha-irradiated BeO surfaces is analyzed by measuring water contact angles (CAs). C and F atoms were created, and consequently, hydrophobic CFx functional groups were formed by the alpha irradiation of hydrophilic BeO. The amount of CFx functional groups on the surface increases as the irradiation time increases. In addition, the surface roughening, which also affects the surface wettability, was induced by the alpha irradiation. Accordingly, the CA of alpha-irradiated BeO surfaces gradually increases as the irradiation time increases. In conclusion, hydrophilic BeO surfaces could be easily converted to hydrophobic surfaces by the alpha irradiation.
	Slides TH1PB04 [5.545 MB]

Paper

Title

Other Keywords

Page

TU1PB02

Electron Cyclotron Resonance Source Development

ion, ECRIS, ECR, ion-source

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

ion, extraction, ECR, ECRIS

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]

TUPPT013

Simulation of Sufficient Spindle Cusp Magnetic Field for 28 GHz ECRIS

ECRIS, ion, ECR, electron

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

ion, electron, proton, ion-source

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.

TUPPT016

Developments of Ion Source Complex for Highly Intense Beam at RCNP

extraction, ion, ECR, emittance

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

ion, ion-source, cyclotron, electron

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

ion, electron, cathode, ion-source

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.

WE2PB02

Vlasov Equation Approach to Space Charge Effects in Isochronous Machines

space-charge, simulation, cyclotron, betatron

310

A.J. Cerfon, O. Bühler, J.V. Guadagni
Courant Institute of Mathematical Sciences, New York University, New York, USA
J.P. Freidberg, F.I. Parra Diaz
MIT/PSFC, Cambridge, Massachusetts, USA

Starting from the collisionless Vlasov equation, we derive two simple coupled two-dimensional fluid equations describing the radial-longitudinal beam vortex motion associated with space charge effects in isochronous cyclotrons. These equations show that the vortex motion can be intuitively understood as the nonlinear advection of the beam by the ExB velocity field, where E is the electric field due to the space charge and B is the applied magnetic field. This explains why elongated beams develop spiral halos while round beams are always stable. Solving the coupled equations numerically, we find good agreement between our model and 3-D Particle-In-Cell OPAL simulations*.
* J.J. Yang, A.Adelmann, M. Humbel, M. Seidel, and T.J. Zhang, Physical Review Special Topics Accelerators and Beams 13, 062401 (2010)

Slides WE2PB02 [1.166 MB]

WE3PB01

Experimental Study of Resonance Crossing with a Paul Trap

resonance, emittance, simulation, ion

409

H. Sugimoto
KEK, Ibaraki, Japan

The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands as in cyclotrons and FFAGs.

Slides WE3PB01 [9.757 MB]

TH1PB04

Fabrication of Hydrophobic Surfaces from Hydrophilic BeO by Alpha-Irradiation-Induced Nuclear Transmutation

controls, radiation, cyclotron, target

443

E.J. Lee, M.G. Hur, J.H. Park
KAERI, Daejon, Republic of Korea
Y.B. Kong, Y.D. Park, J.M. Son, S.D. Yang
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongup-si, Jeollabuk-do, Republic of Korea

Hydrophobic surfaces were simply fabricated by irradiating hydrophilic BeO surfaces with an alpha particle beam from a cyclotron. In this research, BeO disks were irradiated under conditions of ~25 MeV in alpha particle energy and ~1 μA in beam current with different irradiation time. After the alpha irradiation, the changes in the morphology and chemical composition of BeO surfaces were analyzed using a field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The wetting property of alpha-irradiated BeO surfaces is analyzed by measuring water contact angles (CAs). C and F atoms were created, and consequently, hydrophobic CFx functional groups were formed by the alpha irradiation of hydrophilic BeO. The amount of CFx functional groups on the surface increases as the irradiation time increases. In addition, the surface roughening, which also affects the surface wettability, was induced by the alpha irradiation. Accordingly, the CA of alpha-irradiated BeO surfaces gradually increases as the irradiation time increases. In conclusion, hydrophilic BeO surfaces could be easily converted to hydrophobic surfaces by the alpha irradiation.

Slides TH1PB04 [5.545 MB]