Studies of electron cyclotron resonance ion source beam formation, transport and quality
Abstract
This thesis presents the results of a broad study investigating different possibilities
to improve the performance of the JYFL 14 GHz Electron Cyclotron Resonance Ion
Source (ECRIS). The experimental work includes studies of ECRIS plasma, ion beam
formation and beam transport, all of which contribute to the properties of ion beams
produced with ECR ion sources. In particular, it is shown that the degradation of beam
quality due to the formation of hollow beam structure is influenced by phenomena
originating from all of these categories.
The effects of fine tuning the frequency of the plasma heating microwaves of the JYFL
14 GHz ECRIS are presented, showing that the frequency tuning can influence the ion
beam properties. It is demonstrated that the ion beams produced with the ion source
are not completely space charge compensated during the first section of the beam
transport, and the space charge effects in this region have significant impact on the
beam properties. Also, it is shown that mitigating these effects can lead to substantial
improvement in beam quality. The temporal stability of ion beams produced with
ECR ion sources is discussed and it is shown that the beams exhibit fast beam current
oscillations in the 102 − 103 Hz region, characteristics of which depend on the ion
source tuning. Experiments with the so-called collar structure are presented, providing
new insight into the plasma conditions near the ion extraction. As a culmination of
the thesis work, a new extraction system has been designed and constructed for the
JYFL 14 GHz ECRIS. It is shown that the new system provides improved performance
compared to the old one in terms of extracted beam currents, beam quality and
transmission efficiency.
Main Author
Format
Theses
Doctoral thesis
Published
2013
Series
ISBN
978-951-39-5287-7
Publisher
University of Jyväskylä
The permanent address of the publication
https://urn.fi/URN:ISBN:978-951-39-5287-7Käytä tätä linkitykseen.
ISSN
0075-465X
Language
English
Published in
Jyväskylän yliopisto. Fysiikan laitos. Research report
Contains publications
- Artikkeli I: Toivanen, V., Koivisto, H., Steczkiewicz, O., Celona, L., Tarvainen, O., Ropponen, T., Gammino, S., & Ciavola, G. (2010). Effect of ECR ion source frequency tuning on ion beam intensity and quality at Department of Physics, University of Jyväskylä. Review of Scientific Instruments, 81, 02A319. DOI: 10.1063/1.3267287
- Artikkeli II: Toivanen, V., Koivisto, H., Steczkiewicz, O., Celona, L., Tarvainen, O., Ropponen, T., Gammino, S., Mascali, D., & Ciavola, G. (2011). Erratum: Effect of electron cyclotron resonance ion source frequency tuning on ion beam intensity and quality at Department of Physics, University of Jyvaskyla (vol 81, 02A319, 2010). Review of Scientific Instruments, 82(2), 29901. DOI: 10.1063/1.3541812
- Artikkeli III: Toivanen, V., Tarvainen, O., Lyneis, C., Kauppinen, J., Komppula, J., & Koivisto, H. (2012). Electron cyclotron resonance ion source plasma chamber studies using a network analyzer as a loaded cavity probe. Review of Scientific Instruments, 83, 02A306. DOI: 10.1063/1.3660818
- Artikkeli IV: Toivanen, V., Steczkiewicz, O., Tarvainen, O., Ropponen, T., Ärje, J., & Koivisto, H. (2010). The effects of beam line pressure on the beam quality of an electron cyclotron resonance ion source. Nuclear Instruments and Methods in Physics Research Section B, 268, 1508. DOI: 10.1016/j.nimb.2010.01.016
- Artikkeli V: Toivanen, V., Tarvainen, O., Komppula, J., & Koivisto, H. (2013). Oscillations of ECR ion source beam current along the beam transport of the JYFL K-130 cyclotron. Journal of Instrumentation, 8(2), Article T02005. DOI: 10.1088/1748-0221/8/02/T02005
- Artikkeli VI: Toivanen, V., Tarvainen, O., Komppula, J., & Koivisto, H. (2013). The effect of plasma electrode collar structure on the performance of the JYFL 14 GHz electron cyclotron resonance ion source. Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 726, 41-46. DOI: 10.1016/j.nima.2013.05.153
- Artikkeli VII: Toivanen, V., Kalvas, T., Koivisto, H., Komppula, J., & Tarvainen, O. (2013). Double einzel lens extraction for the JYFL 14 GHz ECR ion source designed with IBSimu. Journal of Instrumentation, 8(5), Article P05003. DOI: 10.1088/1748-0221/8/05/P05003
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