• 한국초전도ㆍ저온공학회논문지
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• 제24권4호
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• pp.65-70
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• 2022

A vacuum system is designed for thermal insulation of a 10 ton/day class air liquefaction cold box for liquid air energy storage. The vacuum system is composed of a turbomolecular pump, a backing pump and vacuum piping for the vacuum pumps. The turbomolecular pump is in combination with the backing pump for pumping capacity. The vacuum piping is designed with system installation conditions, such as distance from the cold box, connections to vacuum pumps and installation space. The capacity of the vacuum pump combination, namely pumping speed, is determined by analysis of the vacuum system, and pump-down time to 1×10^-5 mbar is estimated. Vacuum piping conductance, system pumping speed and outgassing rate are calculated for the pump-down time with the ultimate pumping speed range of the vacuum pump combination of 1400 - 2300 l/s. Although the pump-down time gets shorter by larger capacity vacuum pumps, it mainly depends on target vacuum degree and outgassing rate in the cold box. The pump-down time is estimated as 3 - 6 hours appropriate for cold box operation for the pumping speed range. Considering the outgassing rate has uncertainty, the vacuum pump combination with pumping speed of 1900 l/s is chosen for the vacuum system, which is middle value of the pumping speed range.

• International journal of advanced smart convergence
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• 제5권2호
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• pp.1-7
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• 2016

Recently, with the development of advanced thin film devices comes the need for constant high quality vacuum as the deposition pressure is more demanding. It is for this reason our research seeks to understand how the variable design factors are employed in such vacuum systems. In this study, the effects of design factor applications on the vacuum characteristics were simulated to obtain the optimum design modeling of variable models on an ultra high vacuum system. The commercial vacuum system simulator, $VacSim^{(multi)}$, was used in our investigation. The reliability of the employed simulator was verified by the simulation of the commercially available models of ultra high vacuum system. Simulated vacuum characteristics of the proposed modeling aligned with the observed experimental behavior of real systems. Simulated behaviors showed the optimum design models for the ideal conditions to achieve optimal pressure, pumping speed, and compression ratio in these systems.

• 한국전기전자재료학회논문지
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• 제24권6호
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• pp.449-457
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• 2011

Effect of pump combinations on the vacuum characteristics of vacuum system was simulated for optimum design of system. In this investigation, the feasibility of modelling mechanism for VacSimMulti simulator was proposed. Simulation results of various pumping combinations showed the possibilities and reliabilities of simulation for the performance of vacuum system in specific semiconductor processing. Simulation of roughing pump presented the expected pumping behaviors based on commercial specifications of employed pumps. Application of booster pump exhibited the high pumping efficiency for middle vacuum range. Combinations of optimum backing pump for diffusion and turbo vacuum system were obtained. And, the predictable characteristics of process application of both simulated systems were also acquired.

• 진공이야기
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• 제1권1호
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• pp.6-10
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• 2014

It is a common sense that water is an old offender crashing our dream of achieving a good vacuum in an early time. Various techniques for accelerating the removal of water have been developed and utilized. However, we generally are not skilled in treating the water pumping in a physically proper manner. We are rather used to handle the situation of the water pumping just like considering a conventional air pumping. Under such an erroneous approach, we cannot help making an overestimation on the pumping capability of our vacuum system, and it leads to a big mismatch between the real operation timing and the planned process schedule. In this article, some main points concerning with the subject that a vacuum pumping is really a water pumping will be discussed.

• 한국진공학회지
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• 제13권2호
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• pp.47-53
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• 2004

국내 진공기술 기반을 구축하는 국가사업의 일환으로 게터펌프 성능평가장치를 개발하고 있다. 본격적으로 장치를 구성하기 전에 평가절차의 개발, 장치 설계요건 및 사양을 확정하기 위해 예비실험장치를 만들었다. 이 장치를 이용하여 밀봉형 기기에 들어가는 비교적 활성화 온도가 낮은 게터 소자들의 특성평가 절차를 만들고 이를 적용하여 수소, 일산화탄소, 질소 등에 대해 배기속도와 배기용량을 측정해 보았다. 주로 고순도 기체 공급장치용으로 국내에서 개발된 게터 소자와 램프용으로 널리 쓰이는 외국제품의 배기성능을 비교해 보았다.

• 한국진공학회지
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• 제8권4B호
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• pp.548-555
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• 1999

The NBI (Neutral BGeam Injection) System for the Korea Superconducting Tokamak Advanced Research (KSTAR) is composed of ion sources, neutralizers, bending magnets, ion dumps, and calorimeter. The vacuum chamber, in which all of the beam line components are enclosed, is composed of differential pumping system for the effective transfer of the neutral beams. The needed pumping speeds of each of the divided vacuum chamber and the optimized gas flow rate ot the neutralizer were calculated with the help of the particle balance equations. The minimum gas flow rate to the ion sources for producing needed beam current (120kV, 65A, 78MW), the pressure distributions in the vacuum chamber for minimizing re-ionization loss, and the beam loss rate on the beam line components were used as the input in the calculation. Also the scenario for short pulse operation was determined by analysing the time dependent equations. It showed that beam extraction during less than 0.5 sec could be made only with TMP.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.217-223
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• 2023

In this study, we compared the VacCAD and VacTran, commercial vacuum simulators, to investigate the simulation applicability and efficiency as vacuum simulation software. It was verified on reliability and simplicity of simulation modelling, and characteristics of the pump combinations, pumping down curves, and employed vacuum materials. First, usability of simulation schematics was estimated through the modeling tools and the overall simulation characteristics of each simulator were compared to evaluate the applicability in practice. Simulation reliability of each simulator was also probed by comparing the pumping performance characteristics of commercial high vacuum system models. In addition, the degree of tolerances on both simulators was also evaluated through pumping down analysis considering outgassing effect due to chamber material variations. The higher effectiveness and expediency of VacCAD than VacTran has been presented, and it was also expected that the utilization of VacTan in vacuum applications to be increased due to the higher availability of modelling variations.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.39-39
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• 1999

The KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak is a nuclear fusion experimental device for a long pulse/steady-state plasma operation, adopting fully superconducting magnets. In accordance with completion of the basic design of the torus vacuum vessel and the enclosing cryostat, the vacuum pumping and gas fueling basic design has been developed to fulfil the physics requirements. The ultra-high vacuum pumping and sophisticated gas fueling system of the machine is essential to achieve such roles for optimized plasma performance and operation. Recently the vacuum exhaust system using dedicated pumping ports for the vacuum vessel and cryostat has been modified to meet more reliable and successful performance of the KSTAR[Fig. 1].In order to achieve the required base pressure of 5 x 10-9 torr, the total impurity load to the vessel internal is limited to ~5 x 10-5 torr-1/x, while the cryostat base pressure is kept as ~5 x 105 torr to mitigate the thermal load applied to the superconducting magnets. Each KSTAR fueling system will be separately capable of fueling gas at a rate of 50 torr-1/x, consistent with the given pumping throughput. In order to initiate a plasma discharge in KSTAR, the vacuum vessel is filled to a gas pressure of few 10-6 to few 10-4 torr, and additional gas injection is required to maintain and increase the plasma density during the course of the discharge period.

• 한국진공학회지
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• 제16권6호
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• pp.405-413
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• 2007

진공시스템 최적화 설계를 위한 시스템 성능에 대한 설계인자 영향이 전산모사로 연구되었다. 본 연구로 상업화 전산모사기인 $VacSim^{Multi}$에 의한 진공시스템 모델링기구가 제시되었으며 진공시스템의 진공생성기구인 펌핑계 설계인자의 영향을 평가하여 향후 여러 설계인자들의 전산모사 연구 가능성이 확인되었다. $VacSim^{Multi}$의 저진공펌프 모델 전산모사 결과와 펌프사양에 의한 배기거동이 오차범위로 일치하였으며 부스터펌프의 사용이 중진공영역 응용에 효과적인 것으로 확인되었다. 또한 자체 배기능력이 없는 유확산펌프와 터보분자펌프 배기계의 최적화보조펌프 조합이 제시되었으며, 유확산 및 터보분자펌프 배기계의 시스템 공정응용특성도 확인되었다.

• Applied Science and Convergence Technology
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• 제25권6호
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• pp.108-115
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• 2016

Even if ion pumps are widely and mostly used in ultra-high vacuum (UHV) conditions, virtually every existing ion pump has its maximum pumping speed around 1E-6 mbar (1E-4 Pa). Discharge intensity in the ion pump Penning cell is defined as the current divided by pressure (I/P). This quantity reflects the rate of cathode bombardment by ions, which underlies all of the various pumping mechanisms that occur in ion pumps (chemisorption on sputtered material, ion burial, etc.), and therefore is an indication of pumping speed. A study has been performed to evaluate the influence of magnetic fields and cell dimensions on the ion pump discharge intensity and consequently on the pumping speed at different pressures. As a result, a combination of parameters has been developed in order to design and build an ion pump with the pumping speed peak shifted towards lower pressures. Experimental results with several different test set-ups are presented and a prototype of a new 200 l/s ion pump with the maximum pumping speed in the 1E-8 mbar (1E-6 Pa) is described. A model of the system has also been developed to provide a framework for understanding the experimental observations.