• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.537-537
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• 2013

Cyclotron-accelerated ion beams are used for various researches, such as nuclear physics, nuclear chemistry, biotechnology, and material sciences including radio-isotope production. Recently considerable applications are asked to the cyclotron development undertaken to meet user requirements of various ions'energies, intensities, and their pulsed beams. For instance, a cocktail beam acceleration technique rapidly changing the ion species and energies was developed to irradiating integrated circuit chips. Also a chopping system in a cyclotron injection line is considered for producing a pulsed ion beam with a relatively long period compared with that generated by the resonance frequency. For the research in neutron time-of-flight measurement, a single-pulsed beam with a repetition interval of the order of mili-seconds or longer is necessary to have a good resolution and to remove background events. In this paper a feasibility of pulsed beam with an external ion source is simulated by adopting a combination system of a chopper accompanying with a bunching stage in the injection line and an additional chopper after the exit of the cyclotron in order to produce beam pulses with a range of $1{\mu}s{\sim}1ms$ periods from a resonance RF cycle. The pulseperiod will be adjusted by chopping the number of beam bunches from the injected pulses in the injection line. However, the longer pulses will have reduced number of beam pulses and sacrificed beam currents. Because the beam users need an intense single pulsed beam, a careful tuning of the acceleration phase and a high-intense external ion source are necessary to achieve an intense single-pulsed beam from the cyclotron. It is essential to strictly match the acceleration phase of injected beams in the central region of the cyclotron to improve its efficiency. An effect of space charge at each pulse from the ion source will be also considered.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.65.4-65.4
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• 2017

The laboratory astrophysics is a new emerging field of basic sciences, and has tremendous discovery potentials. The laboratory astrophysics investigates the basic physical phenomena in the astrophysical objects in controlled and reproducible manners, which has become possible only recently due to the newly-established intense photon and ion beam facilities worldwide. In this presentation, we will introduce several promising ideas for laboratory astrophysics programs that might be readily incorporated in the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). For example, precise spectroscopic measurements using Electron Beam Ion Trap (EBIT) and intense X-ray photons from the PAL-XFEL can be performed to explore the fundamental processes in high energy X-ray phenomena in the visible universe. Besides, in many violent astrophysical events, the energy density of matter becomes so high that the traditional plasma physics description becomes inapplicable. Generation of such high-energy density states can be also be achieved by using the intense photon beams available from the PAL-XFEL.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.57-62
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• 2005

Using intense pulsed ion beam evaporation technique, we have succeeded in the preparation of poly crystalline silicon thin films without impurities on silicon substrate. Good crystallinity and high deposition rate have been achieved without heating the substrate by using lEE. The crystallinity of poly-Si film has been improved with the high density of the ablation plasma. The intense diffraction peaks of poly-Si thin films could be obtained by using the substrate bias system. The crystallinity and the deposition rate of poly-Si thin films were increased by applying (-) bias voltage for the substrate.

• Nuclear Engineering and Technology
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• v.38 no.4
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• pp.319-326
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• 2006

A brief review is presented on the ion beam application in science and technology. ion beams are used very effectively in various fields of science and technology, on the basis of advance in accelerator technology and experimental techniques for ion beam utilization. Recent progress in this field is reviewed in terms of the direct ion beam utilization like ion beam analysis, and the utilization of neutrons as secondary particles.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.1
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• pp.29-33
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• 2010

Titanium nitride (TiN) films were deposited on the polycarbonate substrate by using radio frequency (RF) magnetron sputtering without intentional substrate heating. After deposition, the films were bombarded with intense electron beam for 20 minutes. The intense electron irradiation impacts on the crystalline, hardness and surface roughness of the TiN films. The films irradiated with an electron beam of 300 eV show the small grains on the surface, while as deposited TiN films did not showany grains on the surface. Also the surface harness evaluated with micro indenter was increased up to 18 Gpa at electron energy of 900 eV after electron beam irradiation. In addition, surface root mean square (RMS) roughness of the films irradiated with intense electron beam affected strongly. The films irradiated by electron beam with 900 eV have the lowest roughness of 1.2 nm in this study.

• Korean Journal of Materials Research
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• v.20 no.12
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• pp.636-639
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• 2010

ZnO thin films were prepared on a glass substrate by radio frequency (RF) magnetron sputtering without intentional substrate heating and then surfaces of the ZnO films were irradiated with intense electrons in vacuum condition to investigate the effect of electron bombardment on crystallization, surface roughness, morphology and hydrogen gas sensitivity. In XRD pattern, as deposited ZnO films show a higher ZnO (002) peak intensity. However, the peak intensity for ZnO (002) is decreased with increase of electron bombarding energy. Atomic force microscope images show that surface morphology is also dependent on electron bombarding energy. The surface roughness increases due to intense electron bombardment as high as 2.7 nm. The observed optical transmittance means that the films irradiated with intense electron beams at 900 eV show lower transmittance than the others due to their rough surfaces. In addition, ZnO films irradiated by the electron beam at 900 eV show higher hydrogen gas sensitivity than the films that were electron beam irradiated at 450 eV. From XRD pattern and atomic force microscope observations, it is supposed that intense electron bombardment promotes a rough surface due to the intense bombardments and increased gas sensitivity of ZnO films for hydrogen gas. These results suggest that ZnO films irradiated with intense electron beams are promising for practical high performance hydrogen gas sensors.

• Proceedings of the Korean Vacuum Society Conference
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• 2003.08a
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• pp.219-219
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• 2003

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.131-132
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• 2006

We experimentally demonstrated the synthesis of silicon nanoparticles by using high-density ablation plasma prepared by the interaction of an intense pulsed light-ion beam (LIB) with a target. known as the intense pulsed ion beam evaporation (IBE) method. Light emission was obtained from the silicon nanoparticles. It was determined that the ambient gas reaction is very important and useful method to obtain the photoluminescence from the silicon nanoparticles.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.2
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• pp.92-96
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• 2002

In this paper, we treated the Ni$_3$Al based alloy samples with intense pulsed ion beams (IPIB) at the beam parameters of 250KV acceleration voltage, 100 - 200 A/cm$^2$ current density and 60 u pulse duration. We simulated the thermal-mechanical process near the surface of Ni$_3$Al based alloy with our STEIPIB codes. The surface morphology and the cross-section microstructures of samples were observed with SEM, the composition of the sample surface layer was determined by X-ray Energy Dispersive Spectrometry (XEDS) and the microstructure on the surface was observed by Transmission Electron Microscope (TEM). The results show that heating rate increases with the current density of IPIB and cooling rate reached highest value less than 150 A/cm$^2$. The irradiation of IPIB induced the segregation of Mo and adequate beam parameter can improve anti-oxidation properly of IC6 alloy. Some craters come from extraneous debris and liquid droplets, and some maybe due to the melting of the intersection region of interphase. Increasing the pulse number enlarges average size of craters and decreases number density of craters.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.666-666
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• 2005