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Huh SR, Kim NK, Jang YC, Song JM, Kim GH. Characterization of Two–Radio-Frequency–Driven Dual Antenna Negative Hydrogen Ion Sources. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst14-892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Sung-Ryul Huh
- Seoul National University, Department of Energy Systems Engineering, Seoul, 151-744, Korea
| | - Nam-Kyun Kim
- Seoul National University, Department of Energy Systems Engineering, Seoul, 151-744, Korea
| | - Yun-Chang Jang
- Seoul National University, Department of Energy Systems Engineering, Seoul, 151-744, Korea
| | - Jae-Min Song
- Seoul National University, Department of Energy Systems Engineering, Seoul, 151-744, Korea
| | - Gon-Ho Kim
- Seoul National University, Department of Energy Systems Engineering, Seoul, 151-744, Korea
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Koivisto H, Kalvas T, Tarvainen O, Komppula J, Laulainen J, Kronholm R, Ranttila K, Tuunanen J, Thuillier T, Xie D, Machicoane G. Ion source research and development at University of Jyväskylä: Studies of different plasma processes and towards the higher beam intensities. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:02A725. [PMID: 26931943 DOI: 10.1063/1.4934687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Several ion source related research and development projects are in progress at the Department of Physics, University of Jyväskylä (JYFL). The work can be divided into investigation of the ion source plasma and development of ion sources, ion beams, and diagnostics. The investigation covers the Electron Cyclotron Resonance Ion Source (ECRIS) plasma instabilities, vacuum ultraviolet (VUV) and visible light emission, photon induced electron emission, and the development of plasma diagnostics. The ion source development covers the work performed for radiofrequency-driven negative ion source, RADIS, beam line upgrade of the JYFL 14 GHz ECRIS, and the development of a new room-temperature-magnet 18 GHz ECRIS, HIISI.
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Affiliation(s)
- H Koivisto
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - T Kalvas
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - O Tarvainen
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - J Komppula
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - J Laulainen
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - R Kronholm
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - K Ranttila
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - J Tuunanen
- Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland
| | - T Thuillier
- LPSC, CNRS/IN2P3, Université Grenoble-Alpes1, 53 Rue des Martyrs, 38026 Grenoble Cedex, France
| | - D Xie
- Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - G Machicoane
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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Jung BK, Dang JJ, An YH, Chung KJ, Hwang YS. Development of a novel radio-frequency negative hydrogen ion source in conically converging configuration. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:02B112. [PMID: 24593552 DOI: 10.1063/1.4830424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Volume-produced negative ion source still requires enhancement of current density with lower input RF (radio-frequency) power in lower operating pressure for various applications. To confirm recent observation of efficient negative ion production with a short cylindrical chamber with smaller effective plasma size, the RF-driven transformer-coupled plasma H(-) ion source at Seoul National University is modified by adopting a newly designed quartz RF window to reduce the chamber length. Experiments with the reduced chamber length show a few times enhancement of H(-) ion beam current compared to that extracted from the previous chamber design, which is consistent with the measured H(-) ion population. Nevertheless, decrease in H(-) ion beam current observed in low pressure regime below ∼5 mTorr owing to insufficient filtering of high energy electrons in the extraction region needs to be resolved to address the usefulness of electron temperature control by the change of geometrical configuration of the discharge chamber. A new discharge chamber with conically converging configuration has been developed, in which the chamber diameter decreases as approaching to the extraction region away from the planar RF antenna such that stronger filter magnetic field can be utilized to prohibit high energy electrons from transporting to the extraction region. First experimental results for the H(-) ion beam extraction with this configuration show that higher magnetic filter field makes peak negative beam currents happen in lower operating pressure. However, overall decrease in H(-) ion beam current due to the change of chamber geometry still requires further study of geometrical effect on particle transport and optimization of magnetic field in this novel configuration.
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Affiliation(s)
- B K Jung
- Department of Nuclear Engineering, Seoul National University, Seoul 151-742, South Korea
| | - J J Dang
- Department of Nuclear Engineering, Seoul National University, Seoul 151-742, South Korea
| | - Y H An
- Department of Nuclear Engineering, Seoul National University, Seoul 151-742, South Korea
| | - K J Chung
- Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-742, South Korea
| | - Y S Hwang
- Department of Nuclear Engineering, Seoul National University, Seoul 151-742, South Korea
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Chung KJ, Jung BK, An Y, Dang JJ, Hwang YS. Effects of discharge chamber length on the negative ion generation in volume-produced negative hydrogen ion source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:02B119. [PMID: 24593559 DOI: 10.1063/1.4842316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In a volume-produced negative hydrogen ion source, control of electron temperature is essential due to its close correlation with the generation of highly vibrationally excited hydrogen molecules in the heating region as well as the generation of negative hydrogen ions by dissociative attachment in the extraction region. In this study, geometric effects of the cylindrical discharge chamber on negative ion generation via electron temperature changes are investigated in two discharge chambers with different lengths of 7.5 cm and 11 cm. Measurements with a radio-frequency-compensated Langmuir probe show that the electron temperature in the heating region is significantly increased by reducing the length of the discharge chamber due to the reduced effective plasma size. A particle balance model which is modified to consider the effects of discharge chamber configuration on the plasma parameters explains the variation of the electron temperature with the chamber geometry and gas pressure quite well. Accordingly, H(-) ion density measurement with laser photo-detachment in the short chamber shows a few times increase compared to the longer one at the same heating power depending on gas pressure. However, the increase drops significantly as operating gas pressure decreases, indicating increased electron temperatures in the extraction region degrade dissociative attachment significantly especially in the low pressure regime. It is concluded that the increase of electron temperature by adjusting the discharge chamber geometry is efficient to increase H(-) ion production as long as low electron temperatures are maintained in the extraction region in volume-produced negative hydrogen ion sources.
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Affiliation(s)
- Kyoung-Jae Chung
- Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744, South Korea
| | - Bong-Ki Jung
- Department of Nuclear Engineering, Seoul National University, Seoul 151-744, South Korea
| | - YoungHwa An
- Department of Nuclear Engineering, Seoul National University, Seoul 151-744, South Korea
| | - Jeong-Jeung Dang
- Department of Nuclear Engineering, Seoul National University, Seoul 151-744, South Korea
| | - Y S Hwang
- Center for Advance Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744, South Korea
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