Studies of electron cyclotron resonance ion source beam formation, transport and quality
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. ...
PublisherUniversity of Jyväskylä
- 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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Dynamic regimes of cyclotron instability in the afterglow mode of minimum-B electron cyclotron resonance ion source plasma Mansfeld, D.; Izotov, I.; Skalyga, V.; Tarvainen, Olli; Kalvas, Taneli; Koivisto, Hannu; Komppula, Jani; Kronholm, Risto; Laulainen, Janne (Institute of Physics Publishing, 2016)The paper is concerned with the dynamic regimes of cyclotron instabilities in non-equilibrium plasma of a minimum-B electron cyclotron resonance ion source operated in pulsed mode. The instability appears in decaying ion ...
Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL Delahaye, P.; Galata, A.; Angot, J.; Ban, G.; Celona, L.; Choinski, J.; Gmaj, P.; Jakubowski, A.; Jardin, P.; Kalvas, Taneli; Koivisto, Hannu; Kolhinen, Veli; Lamy, T.; Lunney, David; Maunoury, L.; Porcellato, A.M.; Prete, Gian Franco; Steckiewicz, O.; Sortais, P.; Thuillier, T.; Tarvainen, Olli; Traykov, E.; Varenne, F.; Wenander, F. (American Institute of Physics, 2012)As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state ...
Electron heating, time evolution of bremsstrahlung and ion beam current in electron cyclotron resonance ion sources Ropponen, Tommi (University of Jyväskylä, 2010)This thesis is a study of Electron Cyclotron Resonance Ion Source (ECRIS) plasmas and their properties. The focus has been on time evolution studies of bremsstrahlung emission, ion beam current production and numerical ...
The biased disc of an electron cyclotron resonance ion source as a probe of instability-induced electron and ion losses Tarvainen, O.; Kronholm, R.; Kalvas, T.; Koivisto, H.; Izotov, I.; Skalyga, V.; Toivanen, V.; Maunoury, L. (American Institute of Physics, 2019)Electron Cyclotron Resonance Ion Source (ECRIS) plasmas are prone to kinetic instabilities resulting in loss of electron and ion confinement. It is demonstrated that the biased disk of an ECRIS can be used as a probe to ...
Koivisto, Hannu; Suominen, Pekka; Tarvainen, Olli; Spädtke, P. (American Institute of Physics, 2012)The main limitation to further improve the performance of ECR ion sources is set by the magnet technology related to the multipole magnet field used for the closed minimum-B structure. The JYFL ion source group has sought ...