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Title: First operation and effect of a new tandem-type ion source based on electron cyclotron resonance

Abstract

A new tandem type source has been constructed on the basis of electron cyclotron resonance plasma for producing synthesized ion beams in Osaka University. Magnetic field in the first stage consists of all permanent magnets, i.e., cylindrically comb shaped one, and that of the second stage consists of a pair of mirror coil, a supplemental coil and the octupole magnets. Both stage plasmas can be individually operated, and produced ions in which is energy controlled by large bore extractor also can be transported from the first to the second stage. We investigate the basic operation and effects of the tandem type electron cyclotron resonance ion source (ECRIS). Analysis of ion beams and investigation of plasma parameters are conducted on produced plasmas in dual plasmas operation as well as each single operation. We describe construction and initial experimental results of the new tandem type ion source based on ECRIS with wide operation window for aiming at producing synthesized ion beams as this new source can be a universal source in future.

Authors:
; ; ; ; ; ; ; ; ;  [1]
  1. Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)
Publication Date:
OSTI Identifier:
22482871
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; CYLINDRICAL CONFIGURATION; ECR ION SOURCES; ELECTRON CYCLOTRON-RESONANCE; ION BEAMS; MAGNETIC FIELDS; MAGNETIC MIRRORS; OPERATION; PERMANENT MAGNETS; PLASMA

Citation Formats

Kato, Yushi, E-mail: kato@eei.eng.osaka-u.ac.jp, Kimura, Daiju, Yano, Keisuke, Kumakura, Sho, Imai, Youta, Nishiokada, Takuya, Nagaya, Tomoki, Hagino, Shogo, Otsuka, Takuro, and Sato, Fuminobu. First operation and effect of a new tandem-type ion source based on electron cyclotron resonance. United States: N. p., 2016. Web. doi:10.1063/1.4933122.
Kato, Yushi, E-mail: kato@eei.eng.osaka-u.ac.jp, Kimura, Daiju, Yano, Keisuke, Kumakura, Sho, Imai, Youta, Nishiokada, Takuya, Nagaya, Tomoki, Hagino, Shogo, Otsuka, Takuro, & Sato, Fuminobu. First operation and effect of a new tandem-type ion source based on electron cyclotron resonance. United States. doi:10.1063/1.4933122.
Kato, Yushi, E-mail: kato@eei.eng.osaka-u.ac.jp, Kimura, Daiju, Yano, Keisuke, Kumakura, Sho, Imai, Youta, Nishiokada, Takuya, Nagaya, Tomoki, Hagino, Shogo, Otsuka, Takuro, and Sato, Fuminobu. 2016. "First operation and effect of a new tandem-type ion source based on electron cyclotron resonance". United States. doi:10.1063/1.4933122.
@article{osti_22482871,
title = {First operation and effect of a new tandem-type ion source based on electron cyclotron resonance},
author = {Kato, Yushi, E-mail: kato@eei.eng.osaka-u.ac.jp and Kimura, Daiju and Yano, Keisuke and Kumakura, Sho and Imai, Youta and Nishiokada, Takuya and Nagaya, Tomoki and Hagino, Shogo and Otsuka, Takuro and Sato, Fuminobu},
abstractNote = {A new tandem type source has been constructed on the basis of electron cyclotron resonance plasma for producing synthesized ion beams in Osaka University. Magnetic field in the first stage consists of all permanent magnets, i.e., cylindrically comb shaped one, and that of the second stage consists of a pair of mirror coil, a supplemental coil and the octupole magnets. Both stage plasmas can be individually operated, and produced ions in which is energy controlled by large bore extractor also can be transported from the first to the second stage. We investigate the basic operation and effects of the tandem type electron cyclotron resonance ion source (ECRIS). Analysis of ion beams and investigation of plasma parameters are conducted on produced plasmas in dual plasmas operation as well as each single operation. We describe construction and initial experimental results of the new tandem type ion source based on ECRIS with wide operation window for aiming at producing synthesized ion beams as this new source can be a universal source in future.},
doi = {10.1063/1.4933122},
journal = {Review of Scientific Instruments},
number = 2,
volume = 87,
place = {United States},
year = 2016,
month = 2
}
  • A new tandem type source has been constructed on the basis of electron cyclotron resonance (ECR) plasma for producing synthesized ion beams. We investigate feasibility and hope to realize the device which has wide range operation window in a single device to produce many kinds of ion beams based on ECR ion source (ECRIS). It is considered that ECR plasmas are necessary to be available to individual operations with different plasma parameters. Both of analysis of ion beams and investigation of plasma parameters are conducted on produced plasmas. We describe construction of the new tandem type ion source based onmore » ECRIS with wide operation window for aiming at producing synthesized ion beams as this new source can be a universal source.« less
  • The 14.5 GHz electron-cyclotron-resonance ion source (ECRIS) designed and fabricated specifically for charge breeding has been installed at the Texas A and M University Cyclotron Institute for use in the institute's ongoing radioactive-ion-beam upgrade. The initial testing of the source has just begun with magnetic analysis of the ECRIS beam. The source has only been conditioning for a brief time at low microwave power, and it is continuing to improve. After the source has been conditioned and characterized, charge-breeding trials with stable beams from a singly ionizing source will begin.
  • We suggest a Penning-type discharge as a trigger discharge for fast development of pulsed electron cyclotron resonance plasma. The Penning-type discharge glows at a low pressure as needed. Gyrotron radiation (75 GHz, 200 kW, 1 ms) was used for plasma heating. Fully striped helium ions were demonstrated, average charge of ions in the plasma was {approx_equal} 2. Experiment and calculations show that high charge states of heavier gases require lower initial pressure and longer development time. Only moderate charge states are achievable in this pulsed scheme.
  • The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system andmore » the cavity behavior of the plasma chamber cannot be separated. A preferable approach to study the effect of the cavity properties of the plasma chamber on extracted beam currents is to adjust the cavity dimensions. The results of such cavity tuning experiments conducted with the JYFL 14 GHz ECRIS are reported here. The cavity properties were adjusted by inserting a conducting tuner rod axially into the plasma chamber. The extracted beam currents of oxygen charge states O{sup 3+}–O{sup 7+} were recorded at various tuner positions and frequencies in the range of 14.00–14.15 GHz. It was observed that the tuner position affects the beam currents of high charge state ions up to several tens of percent. In particular, it was found that at some tuner position / frequency combinations the plasma exhibited “mode-hopping” between two operating regimes. The results improve the understanding of the role of plasma chamber cavity properties on ECRIS performances.« less
  • We measured the main plasma parameters (density of electron, temperature of electrons, and ion confinement time) as a function of B{sub min} and B{sub inj} with laser ablation technique. We observed that the B{sub min} mainly affects the temperature and density of electrons and all of the three parameters increase with increasing the B{sub inj}. We also observed that the gas pressure of the plasma chamber at the rf injection side became minimum at the optimum value for B{sub min} at fixed gas flow. This result indicates that the ionization efficiency becomes maximum at optimum value for B{sub min}. Frommore » these results, it is concluded that the plasma production is strongly dependent on the B{sub min} (plasma generator). We also observed that the B{sub inj} affects the ion confinement time, temperature, and density of electrons. All of the three parameters increase with increasing B{sub inj}.« less