• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.494-499
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• 2004

A ion source using inductively coupled plasma has been tested in order to test its feasibility as a high brightness ion source for focused ion beam. When operating the ion source with filter magentas in front of plasma electrode for a negative ion source, lower remittances are expected. Extracted beam remittances are measured with an Allison-type scanning device for various plasma parameters and extraction conditions. The normalized omittance has been measured to be around 0.2$\pi$mmmrad with beam currents of up to 0.55 ㎃. In particular, noting that multicusp magnets have a role in decreasing the remittance as well as increasing plasma discharge efficiency, transverse magnetic field has been confirmed to be a useful tool fur decreasing remittance via electron energy control.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.507-510
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• 2004

Oblique ion-induced secondary electron emission coefficient(${\gamma}$) with low energy ..and work function ${\phi}_{\omega}$(${\theta}$ = 0 and ${\theta}$ = 20) of the MgO thin film in AC-PDPs has been measured by ${\gamma}$-FIB system. The MgO thin film has been deposited from sintered material under electron beam evaporation method. The energy of $He^+$ ions used has been ranged from 50eV to 150eV. Oblique ion beam has been chosen to be 10 degree, 20 degree and 30 degree. It is found that the higher secondary electron emission coefficient(${\gamma}$) has been achieved by the higher oblique ion beam up to inclination angle of 30 degree than the perpendicular incident ion beam.

• Journal of the Korean institute of surface engineering
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• v.37 no.4
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• pp.220-225
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• 2004

A new ion beam extraction system is designed using a simple ion mass filter and a micro mass balance and a QMS based detecting system. A quadrupole Mass Filter is used for selective ion beam formation from inductively coupled high density plasma sources with appropriate electrostatic lens and final analyzing QMS. Also a quartz crystal microbalance is set between a QMF and a QMS to measure the etching and polymerization rate of the mass selected ion beam. An inductively coupled plasma was used as a ion/radical source which had an electron temperature of 4-8 eV and electron density of $4${\times}$10^{11}$＃/㎤. A computer interfaced system through 12bit AD-DA board can control the pass ion mass of the qmf by setting RF/DC voltage ratio applied to the quadrupoles so that time modulation of pass ion's mass is possible. So the direct measurements of ion - surface chemistry can be possible in a resolution of $1\AA$/sec based on the qcm's sensitivity. A full set of driving software and hardware setting is successfully carried out to get fundamental plasma information of the ICP source and analysed $Ar^{+}$ beam was detected at the $2^{nd}$ QMS.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.802-805
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• 2003

The ion-induced secondary electron emission coefficient ${\gamma}$ for MgO thin film with $O_{2}$ plasma treatment has been investigated by ${\gamma}$-FIB (focused ion beam) system. The MgO thin film deposited from sintered material with $O_2$ plasma treatment is found to have higher ${\gamma}$ than that without $O_{2}$ plasma treatment. The energy of $Ne^{+}$ ions used has been ranged from 100eV to 200eV throughout this experiment. It is found that the highest secondary electron emission coefficient ${\gamma}$ has been achieved for 10 minutes of $O_{2}$ plasma treatment.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.525-528
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• 2004

The ion-induced secondary electron emission coefficient ${\gamma}$ and work function for MgO thin film with $O_2$ plasma treatment has been investigated by ${\gamma}$ -FIB (focused ion beam) system. The MgO thin film deposited from sintered material with $O_2$ plasma treatment is found to have higher ${\gamma}$ and lower work function than those without $O_2$ plasma treatment. The energy of various ions used has been ranged from 100eV to 200eV throughout this experiment. It is found that the highest secondary electron emission coefficient ${\gamma}$ has been achieved for 10 minutes of $O_2$ plasma treatment under RF power of 50W.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.269-269
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• 2012

A new ion source has been designed, fabricated, and installed at the NBTS (Neutral Beam Test Stand) at the KAERI (Korea Atomic Energy Research Institute) site. The goalis to provide a 100 keV, 2MW deuterium neutral beam injection as an auxiliary heating of KSTAR (Korea Super Tokamak Advanced Research). To cope with power demand, an ion current of 50 A is required considering the beam power loss and neutralization efficiency. The new ion source consists of a magnetic cusp bucket plasma generator and a set of tetrode accelerators with circular copper apertures. The plasma generator for the new ion source has the same design concept as the modified JAEA multi-cusp plasma generator for the KSTAR prototype ion source. The dimensions of the plasma generator are a cross section of $59{\times}25cm^2$ with a 32.5 cm depth. The anode has azimuthal arrays of Nd-Fe permanent magnets (3.4 kG at surface) in the bucket and an electron dump, which makes 9 cusp lines including the electron dump. The discharge properties were investigated preliminarily to enhance the efficiency of the beam extraction. The discharge of the new ion source was mainly controlled by a constant power mode of operation. The discharge of the plasma generator was initiated by the support of primary electrons emitted from the cathode, consisting of 12 tungsten filaments with a hair-pin type (diameter = 2.0 mm). The arc discharge of the new ion source was achieved easily up to an arc power of 80 kW (80 V/1000 A) with hydrogen gas. The 80 kW capacity seems sufficient for the arc power supply to attain the goal of arc efficiency (beam extracted current/discharge input power = 0.8 A/kW). The accelerator of the new ion source consists of four grids: plasma grid (G1), gradient grid (G2), suppressor grid (G3), and ground grid (G4). Each grid has 280 EA circular apertures. The performance tests of the new ion source accelerator were also finished including accelerator conditioning. A hydrogen ion beam was successfully extracted up to 100 keV /60 A. The optimum perveance is defined where the beam divergence is at a minimum was also investigated experimentally. The optimum hydrogen beam perveance is over $2.3{\mu}P$ at 60 keV, and the beam divergence angle is below $1.0^{\circ}$. Thus, the new ion source is expected to be capable of extracting more than a 5 MW deuterium ion beam power at 100 keV. This ion source can deliver ~2 MW of neutral beam power to KSTAR tokamak plasma for the 2012 campaign.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.97-97
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• 2009

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.799-801
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• 2003

The secondary electron emission $coefficient({\bullet})$ of vacuum annealed MgO films has been investigated by ${\bullet}$ -focused ion beam(${\bullet}$ -FIB) system. The vacuum annealed MgO films have been found to have higher ${\bullet}$ values than those for as-deposited MgO films for Ne+ ion. Also it is found that the ${\bullet}$ for air-hold of vacuum annealed MgO layers for 24-hours is similar to that for vacuum annealed MgO films without any air-hold.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.546-551
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• 2024

As an effective methods of plasma heating, neutral beam injection (NBI) systems based on negative hydrogen ion sources will be utilized in future magnetic-confinement nuclear fusion experiments. Because of the collisions between the fast negative ions and the neutral background gas, the positive ions are inevitable created in the acceleration region in the negative NBI system. These positive ions are accelerated back into the ion source and become high energy backstreaming ions. In order to explore the characters of backstreaming ions, the track and power deposition of backstreaming H⁺ beam is estimated using the experimental and simulation methods at NNBI test facility. Results show that the flux of backstreaming positive ions is 1.93 % of that of negative ion extraction from ion source, and the magnet filed in the beam source has an effect on the backstreaming positive ions propagation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.595-596
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• 2013