ECRIS2012 - List of Keywords (simulation)

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

TUZO04	Space Charge Compensation Measurements of Multicharged Ion Beams Extracted from an ECR Ion Source	ion, space-charge, electron, ECR	38
	D. Winklehner LBNL, Berkeley, California, USA D.G. Cole, D. Leitner, G. Machicoane, F. Marti, L. Tobos NSCL, East Lansing, Michigan, USA
	Space charge compensation* due to the interaction of the beam with residual gas molecules is a well-known phenomenon for high current injector beam lines. For beam lines using mostly magnetic focusing elements and for pressure above 10^-6 mbar, full neutralization has been observed. However, due to the low pressure required for the efficient transport of high charge state ions, beams in ECR injector lines are typically only partly neutralized. With the performance increase of the next generation ECR ion sources it is possible to extract tens of mA of beam current. In this high current regime, non-linear focusing effects due to the space-charge potential of the beam become more and more important. In order to develop a realistic simulation model for low energy beam transport lines, it is important to estimate the degree of space charge compensation. In this contribution we report on measurements of the beam potential (and neutralization), performed after the extraction region of the ECR ion source, in dependence of the base pressure in the beam line and other source parameters using a Retarding Field Analyzer (RFA). Results are discussed and compared to simulations. * When the beam interacts with the residual gas, electrons are separated from gas molecules and accumulate inside the beam envelope, thereby compensating the space-charge (aka neutralization)
	Slides TUZO04 [4.192 MB]

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

WEYO01	The Einzel Lens Longitudinal Chopper	ion, acceleration, injection, induction	95
	K. Takayama, T. Adachi KEK, Ibaraki, Japan T. Adachi, K.W. Leo Sokendai, Ibaraki, Japan
	The Einzel lens longitudinal chopper [1] placed just after the ECRIS has been developed for the KEK digital accelerator [2] and is being operated without trouble over more than 1 year. Propagation of a msec-long ion pulse extracted with the ECRIS extraction voltage V1, is fully controlled by superimposing a rectangular-shape pulse voltage V2 (<0) on the fixed Einzel lens voltage V3 (V3 > V1). For most of time region (~msec), beam propagation is blocked, meanwhile for a time region (~5 μs), where V2 is on and V2 + V3 < V1, the beam can propagate downstream under the optimized transverse matching condition. Namely, the superimposed voltage V2 + V3 works as a gate voltage. This negative pulse voltage is produced by the solid-state switch driven Marx Generator, promising a fast rising/falling feature in the pulse profile. This chopper enjoys a lot of figure of merits originated from the fact that the beam can be handled at its minimum energy region: low electron emission, low voltage, low energy X-ray, and low cost. This type chopper should be expected in a wide variety of ion beam applications. Comparison with other type choppers will be discussed. [1] T. Adachi, K.W. Leo et al., "A Solid-state Marx Generator driven Einzel Lens Chopper", Rev. Sci. Inst. 82, 083305 (2011). [2] T.Iwashita et al., "KEK Digital Accelerator", Phys. Rev. ST-AB 14, 071301 (2011).
	Slides WEYO01 [5.566 MB]

Paper

Title

Other Keywords

Page

TUZO03

New Extraction Design for the JYFL 14 GHz ECRIS

extraction, ion, plasma, space-charge

34

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

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

Slides TUZO03 [4.470 MB]

TUZO04

Space Charge Compensation Measurements of Multicharged Ion Beams Extracted from an ECR Ion Source

ion, space-charge, electron, ECR

38

D. Winklehner
LBNL, Berkeley, California, USA
D.G. Cole, D. Leitner, G. Machicoane, F. Marti, L. Tobos
NSCL, East Lansing, Michigan, USA

Space charge compensation* due to the interaction of the beam with residual gas molecules is a well-known phenomenon for high current injector beam lines. For beam lines using mostly magnetic focusing elements and for pressure above 10^-6 mbar, full neutralization has been observed. However, due to the low pressure required for the efficient transport of high charge state ions, beams in ECR injector lines are typically only partly neutralized. With the performance increase of the next generation ECR ion sources it is possible to extract tens of mA of beam current. In this high current regime, non-linear focusing effects due to the space-charge potential of the beam become more and more important. In order to develop a realistic simulation model for low energy beam transport lines, it is important to estimate the degree of space charge compensation. In this contribution we report on measurements of the beam potential (and neutralization), performed after the extraction region of the ECR ion source, in dependence of the base pressure in the beam line and other source parameters using a Retarding Field Analyzer (RFA). Results are discussed and compared to simulations.
* When the beam interacts with the residual gas, electrons are separated from gas molecules and accumulate inside the beam envelope, thereby compensating the space-charge (aka neutralization)

Slides TUZO04 [4.192 MB]

WEXO02

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

electron, plasma, ion, ECRIS

77

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

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

Slides WEXO02 [11.678 MB]

WEYO01

The Einzel Lens Longitudinal Chopper

ion, acceleration, injection, induction

95

K. Takayama, T. Adachi
KEK, Ibaraki, Japan
T. Adachi, K.W. Leo
Sokendai, Ibaraki, Japan

The Einzel lens longitudinal chopper [1] placed just after the ECRIS has been developed for the KEK digital accelerator [2] and is being operated without trouble over more than 1 year. Propagation of a msec-long ion pulse extracted with the ECRIS extraction voltage V1, is fully controlled by superimposing a rectangular-shape pulse voltage V2 (<0) on the fixed Einzel lens voltage V3 (V3 > V1). For most of time region (~msec), beam propagation is blocked, meanwhile for a time region (~5 μs), where V2 is on and V2 + V3 < V1, the beam can propagate downstream under the optimized transverse matching condition. Namely, the superimposed voltage V2 + V3 works as a gate voltage. This negative pulse voltage is produced by the solid-state switch driven Marx Generator, promising a fast rising/falling feature in the pulse profile. This chopper enjoys a lot of figure of merits originated from the fact that the beam can be handled at its minimum energy region:

low electron emission,
low voltage,
low energy X-ray, and
low cost.

This type chopper should be expected in a wide variety of ion beam applications. Comparison with other type choppers will be discussed.
[1] T. Adachi, K.W. Leo et al., "A Solid-state Marx Generator driven Einzel Lens Chopper", Rev. Sci. Inst. 82, 083305 (2011).
[2] T.Iwashita et al., "KEK Digital Accelerator", Phys. Rev. ST-AB 14, 071301 (2011).

Slides WEYO01 [5.566 MB]