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| MOPO-03 |
Conceptual Design for a Sputter-type Negative Ion Source Based on Electron Cyclotron Resonance Plasma Heating
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64 |
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- O. A. Tarvainen, S. S. Kurennoy
LANL, Los Alamos, New Mexico
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Funding: This work was supported by the US Department of Energy under Contract Number DE-AC52-06NA25396.
A conceptual design for a negative ion source based on electron cyclotron resonance plasma heating and surface ionization is presented. The plasma chamber of the source is an rf-cavity designed for TE111 eigenmode at 2.45 GHz. The desired mode is excited with a loop-antenna. The ionization process takes place on a cesiated surface of a biased converter electrode (cathode) sputtered by plasma ions. The ion beam is 'self-extracted' through the plasma. The magnetic field of the source is optimized for both, plasma generation by ECR heating, and beam extraction. The source can be used for production of negative ions ranging from hydrogen to heavy ions. The potential users for the source concept range from large scale accelerator facilities, utilizing H- ion beams, to dc tandem accelerators for heavy ions. The benefits of the source concept compared to widely used filament- and inductively coupled rf-driven sputter-type sources are the lack of consumable parts and low neutral gas pressure minimizing the stripping losses of negative ions. In this article we will focus on the H- production scenarios with the source. The benefits and drawbacks of higher frequency operations are discussed.
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| TUCO-D01 |
Measurements of Electron Cyclotron Resonance Ion Source Bremsstrahlung Time Evolution and Preglow Effect
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160 |
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- T. Ropponen, P. Jones, T. Kalvas, H. A. Koivisto, P. Peura
JYFL, Jyvaskyla
- P. Suominen
Prizztech Ltd, Magnet Technology Centre, Pori
- O. A. Tarvainen
LANL, Los Alamos, New Mexico
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In order to understand properly the ECR heating and hot electron generation time evolution, measurements of ECRIS bremsstrahlung in radial direction using pulsed RF power with JYFL 14 GHz ECRIS have been performed. The effects of RF power, plasma species, neutral gas pressure and axial magnetic field strength were studied. So-called "preglow effect" for different charge states was studied in conjunction with the bremsstrahlung measurements. An analysis code that combines the bremsstrahlung data i.e. energy and time of incidence from consecutive RF pulses has been written. This method ensures that enough statistics is used for interpretation of the results. Pile-ups, ADC overflows and such disturbances are removed from the Ge detector spectra by using digital signal processing unit. In this paper the time evolution of the electron population with energies over 15 keV in millisecond region time intervals will be presented and the time scale of the preglow effect is connected into the development of the electron energy distribution.
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Slides
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