• Title/Summary/Keyword: Electron range

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Energy Distribution Function for Electrons in $SF_6$+He mixtures gas used by MCS-BEq (MCS-BEq에 의한 $SF_6$-He 혼합기체의 에너지 분포함수)

  • Seong, Nak-Jin;Kim, Sang-Nam
    • Proceedings of the KIEE Conference
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    • 2004.07e
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    • pp.41-44
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    • 2004
  • This paper describes the electron transport characteristics in $SF_6$-He gas calculated for range of E/N values from 50${\sim}$700[Td] by the Monte Carlo simulation(MCS) and Boltzmann equation(BEq) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by TOF method. The results gained that the values of the electron swarm parameters such as the electron drift velocity. the electron ionization or attachment coefficients. longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.

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Determination of an Inelastic Collision Cross Sections for C3F8 Molecule by Electron Swarm Method (전자군 방법에 의한 C3F8분자가스의 비탄성충돌단면적의 결정)

  • Jeon Byung-Hoon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.3
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    • pp.301-306
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    • 2006
  • The electron drift velocity W and the product of the longitudinal diffusion coefficient and the gas number density $ND_{L}$ in the $0.525\;\%$ and $5.05\;\%$ $C_{3}F_8-Ar$ mixtures were measured by using the double shutter drift tube with variable drift distance over the E/N range from 0.03 to 100 Td and gas pressure range from 1 to 915 torr. And we determined the electron collision cross sections set for the $C_{3}F_8$ molecule by STEP 1 of electron swarm method using a multi-term Boltzmann equation analysis. Our special attention in the present study was focused upon the vibrational excitation and new excitations cross sections of the $C_{3}F_8$ molecule.

The study of electron transport coefficients in pure $CF_4$ by 2-term approximation of the Boltzmann equation (2항근사 볼츠만 방정식을 이용한 $CF_4$분자가스의 전자수송계수의 해석)

  • Jeon, Byung-Hoon;Ha, Sung-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.29-32
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    • 2001
  • We measured the electron transport coefficients(the electron drift velocity, W, and the longitudinal diffusion coefficient, $D_L$) in pure $CF_4$ over the E/N range from 0.04 Td to 250 Td by the double shutter drift tube. And these electron transport coefficients in pure $CF_4$ were calculated over the E/N range from 0.01 to 250 Td at 1 Torr by using the two-term approximation of the Boltzmann equation.

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Analysis of electron transport properties in $SF_6+N_2$ mixtures gas used by MCS-BE (MCS-BE에 의한 $SF_6+N_2$ 혼합기체의 전자수송특성 해석)

  • 서상현;하성철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.696-699
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    • 1999
  • The electron transport coefficients in $SF_6+N_2$ gas is analysed in range of E/N values from 100~900(Td) by a Monte Carlo simulation and Boltzmann method, using a set of electron collision cross sections determined by the authors. The result of the Monte Carlo simulation such as electron drift velocity, ionization and electron attachment coefficients, longitudinal and transverse diffusion coefficients in nearly agreement with the respective experimental and theoretical for a range of E/N.

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Performance prediction of gamma electron vertex imaging (GEVI) system for interfractional range shift detection in spot scanning proton therapy

  • Kim, Sung Hun;Jeong, Jong Hwi;Ku, Youngmo;Jung, Jaerin;Kim, Chan Hyeong
    • Nuclear Engineering and Technology
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    • v.54 no.6
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    • pp.2213-2220
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    • 2022
  • The maximum dose delivery at the end of the beam range provides the main advantage of using proton therapy. The range of the proton beam, however, is subject to uncertainties, which limit the clinical benefits of proton therapy and, therefore, accurate in vivo verification of the beam range is desirable. For the beam range verification in spot scanning proton therapy, a prompt gamma detection system, called as gamma electron vertex imaging (GEVI) system, is under development and, in the present study, the performance of the GEVI system in spot scanning proton therapy was predicted with Geant4 Monte Carlo simulations in terms of shift detection sensitivity, accuracy and precision. The simulation results indicated that the GEVI system can detect the interfractional range shifts down to 1 mm shift for the cases considered in the present study. The results also showed that both the evaluated accuracy and precision were less than 1-2 mm, except for the scenarios where we consider all spots in the energy layer for a local shifting. It was very encouraging results that the accuracy and precision satisfied the smallest distal safety margin of the investigated beam energy (i.e., 4.88 mm for 134.9 MeV).

Study on Electron Temperature Diagnostic and the ITO Thin Film Characteristics of the Plasma Emission Intensity by the Oxygen Gas Flow (산소 유량별 플라즈마 방출광원 세기에 따른 전자온도 진단과 산화주석박막 특성연구)

  • Park, Hye Jin;Choi, Jin-Woo;Jo, Tae Hoon;Yun, Myoung Soo;Kwon, Gi-Chung
    • Journal of the Korean institute of surface engineering
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    • v.49 no.1
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    • pp.92-97
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    • 2016
  • The plasma has been used in various industrial fields of semiconductors, displays, transparent electrode and so on. Plasma diagnostics is critical to the uniform process and the product. We use the electron temperature of the various plasma parameters for the diagnosis of plasma. Generally, the range of the electron temperature which is used in a semiconductor process used the range of 1 eV to 10 eV. The difference of electron temperature of 0.5 eV has a influence in plasma process. The electron temperature can be measured by the electrical method and the optical method. Measurement of electron temperature for various gas flow rates was performed in DC-magnetron sputter and Inductively Coupled Plasma. The physical properties of the thin film were also determined by changing electron temperatures. The transmittance was measured using the integrating sphere, and wavelength range was measured at 300 ~ 1100 nm. We obtain the thin film of the mobility, resistivity and carrier concentration using the hall measurement system. As to the electron temperature increase, optical and electrical properties decrease. We determine it was influenced by the oxygen flow ratio and plasma.

A Monte-Carlo method and Boltzmann Equation analysis on the electron swarm parameter in SiH$_4$+Ar mixtures gas. ($SiH_4+Ar$ 혼합기체의 전자군 파라미터에 대한 볼츠만 방정식 및 몬테 칼로법 해석)

  • 김대연;하성철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.387-390
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    • 1999
  • Electron swarm parameterdthe drift velocity and longitudinal diffusion coefficienthn $SiH_4-Ar$ mixtures containing 0.5% and 5% monosilane were measured using over the range of E/N from 0.01 to 300 Td at room temperature. Electron swarm parameters in argon were drastically changed by adding a small amount of monosilane. The electron drift velocity in both mixtures showed unusual behaviour against E/N. It had negative slope in the medium range of E/N, yet the slope was not smooth but contained a small hump. The longitudinal diffusion coefficient also showed a corresponding feature in its dependence on E/N. A two-tern approximation of the Boltzmann equation analysis and Monte Carlo simulation have been used to study electron transport coefficients.

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The study of insulation-characteristic in a mixture gas includes $SF_6$ ($SF_6$를 포함하는 혼합가스의 절연특성에 관한 연구)

  • 박명진;김대연;전병훈;하성철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.165-168
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    • 1999
  • The electron transport coefficients in mixture gas includes SF/sub 6/ is analysed in range of E/N values from 60∼800(Td) by the Boltzmann method that using a set of electron collision crass sections determined by the researchers. Swarm parameters in the Boltzmann method simulation such as electron drift velocity, ionization and electron attachment coefficients is in nearly agreement with the respective experimental and theoretical for a range of E/N.

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Electron Microburst Energy Dispersion Calculated by Test Particle Simulation

  • Lee, Jae-Jin;Kim, Yeon-Han;Park, Young-Deuk
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.94.2-94.2
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    • 2011
  • Electron microbursts, energetic electron precipitation having duration less than 1 sec, have been thought to be generated by chorus wave and electron interactions. While the coincidence of chorus and microburst occurrence supports the wave-particle interaction theory, more crucial evidences have not been observed to explain the origin of microbursts. We propose the measurement of energy dispersion of microbursts could be an evidence supporting wave-particle theory. During chorus waves propagate along magnetic field, the resonance condition should be satisfied at different magnetic latitude for different energy electrons. If we observed electron microbursts at low altitude, the arrival time of different energy electrons should make unique dispersion structures. In order to observe such energy dispersion, we need a detector having fast time resolution and wide energy range. Our study is motivated from defining the time resolution and energy range of the detectors required to measure microburst energy dispersions. We performed test particles simulation to investigate how electrons interact with simple coherent waves like chorus waves. We compute a large number of electron's trajectories and successfully produce energy dispersion structures expected when microbursts are observed with 10 msec time resolution detectors at the altitude of 600 km. These results provide useful information in designing electron detectors for the future mission.

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