• Progress in Superconductivity and Cryogenics
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• v.18 no.4
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• pp.40-43
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• 2016

Beam trajectory is needed to be controlled in heavy ion accelerator system. Quadruple magnets are widely used in heavy ion accelerator for focusing the transporting particles. A quadruple triplet system which consists of three consecutive quadrupoles, Q1, Q2 and Q3, is used to control beam trajectory at a focused position. Q1 and Q3 have symmetry with respect to Q2. The beam trajectory in magnet system is affected by higher order fields existed in real fields. For quadrupoles, the representation simulation of beam trajectory was carried out to study the beam trajectory and to estimate an effect of higher order field in triplet system. SCALA program was used to simulate the beam trajectory in $Opera^{TM}$. SCALA can analyze a large number of beam trajectories at the same time by adjusting the size of finite element of the emitter. With $Opera^{TM}$ and $Matlab^{TM}$ programs, the position of focused beam spot in quadruple triplet system can be increased or decreased using evolution strategy (ES) method, therefore the length of triplet system can be controlled. Finally, the quadruple triplet system with the appropriate length and expected beam spot range was suggested in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.335-335
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• 2000

Applications such as unmanned aerial vehicles (UAVs), autonomous underwater vehicles (AUVs) and the time varying nature of their navigation, guidance and control systems motivate an integrated approach to trajectory general ion and trajectory tracking for autonomous vehicles. In this paper, an experimental testbed was designed for studying this integrated trajectory control approach. In this paper we apply the separating approach to an autonomous nonlinear vehicle system. A new linear matrix inequality based H$_{\infty}$ control technique for periodic time-varying systems is applied to the role of trajectory tracking. Trajectory general ion is accomplished by exploit ing the differential flatness property of the vehicle system; this at lows product ion of desired feasible nominal or reference trajectories from certain ″flat'system outputs. Simulation and experimental results are presented showing stable tracking of a periodic circular trajectory.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.18-27
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• 1998

Molecular dynamicsinvestigations of ion implantation considering point defect generation were performed with ion energies in the range of ~1keV, Simulation starts perfect diamond cubic lattice site. Stillinger-Weber potential and ZBL potential were used to calculate forces between atoms. We have simulated slowing-down of ion velocity, ion trajectory and coupled-coing between ion and silicon. We also discussed distribution of point defect using rdial distribution function. We found that interstitial produced by ion bombardment mainly formed interstitial cluster.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.175-182
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• 1994

Backward trajectory analysis was carried out for 41 cases at 850 hPa level and 47 cases at 700 hPa level during the period from May 1992 to August 1993 in order to understand the impact of long-range transported pollutants from the neighboring countries on the distribution pattern of acid rain in Korea. The occurrence frequencies of acid rain were also investigated using the rainwater data observed at 5 stations in the central part of Korea, Kangwha, Seoul, Yangpyong, Hongchon, and Inje. The trajectory analysis showed that westerlies were dominant on 700 hPa level and southwesterlies on 850 hPa level in Korea. The pH values were also often lower when the trajectory was stagnant in the upper air over Korea. However, pH values were normally higher in all directions of flows during the Yellow Sand Period due to the increase of Positive ion components such as $Ca^{+2}$. The pH values were also normally higher when air flows from north or northeast.

• Mass Spectrometry Letters
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• v.4 no.4
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• pp.91-94
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• 2013

We performed computer simulations to improve transmission efficiencies of a dual ion funnel system implemented on an FT-ICR MS. We found that the low m/z range from 50 to 150 could be significantly improved by operating the two ion funnels at different RF amplitudes. These new operational conditions could be applied to analyze metabolome samples, which require high sensitivity in the m/z range from 50 to 1,000.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.771-780
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• 2001

It is indispensable to use the process and device simulation tool in order to analyze accurately the electrical characteristics of ULSI CMOS devices, in addition to developing and manufacturing those devices. The 3D Monte Carlo (MC) simulation result is not efficient for large-area application because of the lack of simulation particles. In this paper is reported a new efficient simulation strategy for 3D MC ion implantation into large-area application using the 3D MC code of TRICSI(TRansport Ions into Crystal Silicon). The strategy is related to our newly proposed split-trajectory method and ion-splitting method(ion-shadowing approach) for 3D large-area application in order to increase the simulation ions, not to sacrifice the simulation accuracy for defects and implanted ions. In addition to our proposed methods, we have developed the cell based 3D interpolation algorithm to feed the 3D MC simulation result into the device simulator and not to diverge the solution of continuous diffusion equations for diffusion and RTA(rapid thermal annealing) after ion implantation. We found that our proposed simulation strategy is very computationally efficient. The increased number of simulation ions is about more than 10 times and the increase of simulation time is not twice compared to the split-trajectory method only.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.28-38
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• 1998

In our paper is reported a new 3D(dimensional) trajectory split approach with greatly improved efficiency for the Monte Carlo simulation of the 3D profiles of implanted ionand point defect concentrations in single-crystal silicon. This approach has been successfully implemented in our TRICSI Monte Carlo code. Combined with the previously developed model for damage accumalation in our TRICSI code, this model allows phasically based dynamic simulation of 3D profiles over an subsequent process simulation such as diffusion modeling and simulation. A typical time saving of over 10 timeshas been achieved for 3D simulation. Our method ensures much better region aground the implanted area. For 1-D simulation, the optimized condition for trajectory split has set to 3,000 pseudoparticles with 2 split branches.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1782-1784
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• 1997

Using particle-in-cell(PIC) and Monte Carlo collision(MCC), we investigate the trajectory of electrons and the characteristics of D.C. discharge In Wire Ion Plasma Source(WIPS).

• Mass Spectrometry Letters
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• v.6 no.3
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• pp.59-64
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• 2015

Quadrupole ion trap mass analyzer with a simplified geometry, namely, the cylindrical ion trap (CIT), has been shown to be well-suited using in miniature mass spectrometry and even in mass spectrometer arrays. Computation of stability regions is of particular importance in designing and assembling an ion trap. However, solving CIT equations are rather more difficult and complex than QIT equations, so, analytical and matrix methods have been widely used to calculate the stability regions. In this article we present the results of numerical simulations of the physical properties and the fractional mass resolutions m/Δm of the confined ions in the first stability region was analyzed by the fifth order Runge-Kutta method (RKM5) at the optimum radius size for both ion traps. Because of similarity the both results, having determining the optimum radius, we can make much easier to design CIT. Also, the simulated results has been performed a high precision in the resolution of trapped ions at the optimum radius size.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.719-720
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• 2004

A multi-megawatt long pulse ion source (LPIS) of neutral beam injector was developed for the KSTAR. Beam extraction experiments of the LPIS were carried out at the neutral beam test stand (NBTS). Design requirements for the ion source were 120 kV/65 A deuterium beam and a 300 s pulse length. A maximum ion density of $9.1310^{11}$ $cm^{-3}$ was measured by using electric probes, and an optimum arc efficiency of 0.46 A/kW was estimated with ion saturation current of the probes, arc power, and total beam area. An arcing problem, caused by the structural defect of decelerating grid supporter, in the third gap was solved by the blocking of backstream ion particles, originated from the plasma in the neutralizer duct, through the unnecessary spaces on the side of grid supporter. A maximum drain power of 1.5 MW (i.e. 70 kV/21 A) with hydrogen was measured for a pulse duration of 0.5 s. Optimum beam perveance was ranged from 0.75 to 0.85. An improved design of accelerator for the effective control of beam particle trajectory should provide higher beam perveance.