Efficient production of multicharged ions has been investigated on the tandem-type ECRIS in Osaka University. According to the consideration of the accessibility conditions of microwaves to resonance and cutoff regions, it was suggested that the upper hybrid resonance (UHR) heating contributed to enhancement of ion beam intensity. In order to enhance multicharged ion beams efficiently, injecting higher frequency microwave with extraordinary (X-mode) toward UHR region has been tried. In this study, 2.45 GHz frequency microwaves are used for conventional ECR discharge, and 9.9 GHz frequency microwaves with X-mode are superimposed for UHR heating. The effects of additive microwave injection are investigated experimentally in terms of plasma parameters and electron energy distribution function (EEDF) measured by Langmuir probe and ion beam current. As the results show, it is confirmed that the electrons in the high energy region are affected by 9.9 GHz X-mode microwave injection from the detailed analysis of EEDF.
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http://dx.doi.org/10.1063/1.4934212 | DOI Listing |
Interactions (Cham)
March 2024
Institute of Physics, The University of Tokyo, Komaba, Meguro-ku, 153-8902 Tokyo Japan.
We have developed a microwave spectrometer for a measurement of the Lamb shift of antihydrogen atoms towards the determination of the antiproton charge radius. The spectrometer consists of two consecutive apparatuses, of which the first apparatus, (HFS), filters out hyperfine states and pre-selects the state, and the second apparatus, (MWS), sweeps the frequency around the target transition to obtain the spectrum. We optimized the geometry of the apparatuses by evaluating the S-parameter that represents the ratio of the reflected microwave signal over the input, utilizing microwave simulations based on the finite element method.
View Article and Find Full Text PDFSci Rep
October 2024
Department of Electronic Engineering, Hanyang University, Seoul, 04763, South Korea.
Nanomicro Lett
July 2024
Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Fudan University, Shanghai, 200438, People's Republic of China.
Broadband electromagnetic (EM) wave absorption materials play an important role in military stealth and health protection. Herein, metal-organic frameworks (MOFs)-derived magnetic-carbon CoNiM@C (M = Cu, Zn, Fe, Mn) microspheres are fabricated, which exhibit flower-like nano-microstructure with tunable EM response capacity. Based on the MOFs-derived CoNi@C microsphere, the adjacent third element is introduced into magnetic CoNi alloy to enhance EM wave absorption performance.
View Article and Find Full Text PDFPLoS One
April 2024
Department of Electrical Engineering, College of Engineering, Qassim University, Unaizah, Saudi Arabia.
To satisfy the requirements of modern communication systems and wearables using 2.4/5.8 GHz band this paper presents a simple, compact, and dual-band solution.
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