• Title/Summary/Keyword: electron beam method

Search Result 503, Processing Time 0.037 seconds

Characteristics of Dose Distribution at Junctional Area Using the Divergency Cutout Block in the Abutted Field of Photon and Electron Beams (광자선과 전자선의 인접조사에서 선속 퍼짐현상이 고려된 전자선 차폐물을 이용한 접합 조사면의 선량분포 특성)

  • Im, In-Chul;Lee, Jae-Seung
    • Journal of Radiation Protection and Research
    • /
    • v.36 no.3
    • /
    • pp.168-173
    • /
    • 2011
  • This study investigated characteristics of dose distribution at junction field of X-ray and electron beams according to the method for fabricating the insert block on the electron cone. Insert block were fabricated to the divergency cutout block and the straight cutout block. For the 6 MV X-ray and 10 MeV nominal energy of electron beam, we was adjacent to the light field of X-ray and electron beam at a surface of matrix chamber and measured to beam profile of abutted field in the 0, 1, 2, 3 cm measurement depth. As a result, characteristics of dose distribution at junction field, straight block was existent that over dose area exceed the give dose more than 5% and under dose area with a rapid change in dose distribution. However, divergency block had remarkably decreased the over dose area caused by the lateral scattering effects of decrease, and being existed uniformity dose distribution in the junction field. Therefore, divergency block were the benefits of radiation dose delivery, in order to applied the clinical, measurement of electron beams according to the fabrication method of the block should be considered carefully.

Preparation Method of Plan-View Transmission Electron Microscopy Specimen of the Cu Thin-Film Layer on Silicon Substrate Using the Focused Ion Beam with Gas-Assisted Etch

  • Kim, Ji-Soo;Nam, Sang-Yeol;Choi, Young-Hwan;Park, Ju-Cheol
    • Applied Microscopy
    • /
    • v.45 no.4
    • /
    • pp.195-198
    • /
    • 2015
  • Gas-assisted etching (GAE) with focused ion beam (FIB) was applied to prepare plan-view specimens of Cu thin-layer on a silicon substrate for transmission electron microscopy (TEM). GAE using $XeF_2$ gas selectively etched the silicon substrate without volume loss of the Cu thin-layer. The plan-view specimen of the Cu thin film prepared by FIB milling with GAE was observed by scanning electron microscopy and $C_S$-corrected high-resolution TEM to estimate the size and microstructure of the TEM specimen. The GAE with FIB technique overcame various artifacts of conventional FIB milling technique such as bending, shrinking and non-uniform thickness of the TEM specimens. The Cu thin film was uniform in thickness and relatively larger in size despite of the thickness of <200 nm.

Phase Identification of Nano-Phase Materials using Convergent Beam Electron Diffraction (CBED) Technique

  • Kim, Gyeung-Ho;Ahn, Jae-Pyoung
    • Applied Microscopy
    • /
    • v.36 no.spc1
    • /
    • pp.47-56
    • /
    • 2006
  • Improvements are made to existing primitive cell volume measurement method to provide a real-time analysis capability for the phase analysis of nanocrystalline materials. Simplification is introduced in the primitive cell volume calculation leading to fast and reliable method for nano-phase identification and is applied to the phase analysis of Mo-Si-N nanocoating layer. In addition, comparison is made between real-time and film measurements for their accuracy of calculated primitive cell volume values and factors governing the accuracy of the method are determined. About 5% accuracy in primitive cell determination is obtained from camera length calibration and this technique is used to investigate the cell volume variation in WC-TiC core-shell microstructure. In addition to chemical compositional variation in core-shell type structure, primitive cell volume variation reveals additional information on lattice coherency strain across the interface.

Electro-optical analysis of a miniaturized electrostatic electron lens (초소형 전자 렌즈의 전자 광학적 분석)

  • Kim, Ho-Seob;Kim, Dae-Wook;Kim, Young-Chul;Choi, Sang-Kuk;Kim, Dae-Yong
    • Korean Journal of Optics and Photonics
    • /
    • v.14 no.2
    • /
    • pp.194-199
    • /
    • 2003
  • The analysis of operation characteristics of a miniaturized electrostatic electron lens system called an Einzel lens was performed using a simulation tool of FCM method. The potential distributions of Einzel lenses operated both in retarding and accelerating modes show similar features. But the electric fields determined from the potential distributions show opposite directions, which results in different features in the electron beam trajectory in each mode of operation. For the same working distance, focusing voltage in the accelerating mode is higher than that in the retarding mode.

A Study on the Interlaminar Fracture Toughness of Glass Fiber Reinforced Plastic Comosites (GFRP 복합재료의 층간파괴인성치에 관한 연구)

  • 박기호
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.35 no.4
    • /
    • pp.410-420
    • /
    • 1999
  • The value of the mode I interlamina fracture toughness, GIC, is calculated by experimental compliance method, modified compliance method and beam theory. The value of the mode II interlamina fracture toughness, GIC, is evaluated by beam method, theory beam theory and compliance method. This paper describes the effect of load pint displacement rate and speicimen geometries for mode I and II interlaminar fracture toughness of glass fiber reinforced plastic composites by using double cantilever beam (DCB) and end notched flexure (ENF) specimen. For the load point displacement rate of increases whereas the value of 2,6 and 10 mm/min the value of GIC decrease as load point displacement rate increases whereas the value of GIC is found to be no significant effect. The value of GIC decreases as initial crack length increases. The fractured surface of the DCB and ENF samples are examined by scanning electron microscopy (SEM).

  • PDF

Dose Characteristics of Total-Skin Electron-Beam Irradiation with Six-Dual Electron Fields (Six-Dual 전자선 조사면에 의한 전신 피부 조사의 선량 특성)

  • Choi, Tae-Jin;Kim, Jin-Hee;Kim, Ok-Bae
    • Radiation Oncology Journal
    • /
    • v.16 no.3
    • /
    • pp.337-345
    • /
    • 1998
  • Purpose : To obtain the uniform dose at limited depth to entire surface of the body, the dose characteristics of degraded electron beam of the large target-skin distance and the dose distribution of the six-dual electron fields were investigated Materials and Method : The experimental dose distributions included the depth dose curve, spatial dose and attenuated electron beam were determined with 300 cm of target-skin distance (TSD) and full collimator size (35*35 $cm^2$ on TSD 100 cm) in 4 MeV electron beam energy. Actual collimated field size of 105 cm * 105 cm at the distance of 300 cm could include entire hemibody. A patient was standing on step board with hands up and holding the pole to stabilize his/her positions for the six-dual fields technique. As a scatter-degrader, 0.5 cm of acrylic plate was inserted at 20 cm from the body surface on the electron beam path to induce ray scattering and to increase the skin dose. Results : The full width at half maximum(FWHM) of dose profile was 130 cm in large field of 105*105 $cm^2$ The width of $100\pm10\%$ of the resultant dose from two adjacent fields which were separated at 25 cm from field edge for obtaining the dose unifomity was extended to 186 cm. The depth of maximum dose lies at 5 mm and the 80$\%$ depth dose lies between 7 and 8 mm for the degraded electron beam by using the 0.5 cm thickness of acrylic absorber. Total skin electron beam irradiation (TSEBI) was carried out using the six dual fields has been developed at Stanford University. The dose distribution in TSEBI showed relatively uniform around the flat region of skin except the protruding and deeply curvatured portion of the body, which showed excess of dose at the former and less dose at the latter. Conclusion : The percent depth dose, profile curves and superimposed dose distribution were investigated using the degraded electron beam through the beam absorber. The dose distribution obtained by experiments of TSEBI showed within$\pm10\%$ difference except the protruding area of skin which needs a shield and deeply curvatured region of skin which needs boosting dose.

  • PDF

Measurement of Energy bands of the MgO Layer in AC-PDPs

  • Jeoung, S.J.;Lee, H.J.;Son, C.G.;Kim, J.H.;Park, E.Y.;Hong, Y.J.;You, N.L.;Lee, S.B.;Han, Y.G.;Jeoung, S.H.;Song, K.B.;Moon, M.W.;Oh, P.Y.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2006.08a
    • /
    • pp.906-909
    • /
    • 2006
  • The secondary electron emission coefficient $({\gamma})$ of the cathode is an important factor for improving the discharge characteristics of AC-PDPs because of its close relationship to discharge voltage. In AC-PDPs, MgO is most widely used as a surface protective layer. In this experimental, we have investigated the electronic structure of the energy band structure of the MgO layer responsible for the high ${\gamma}$. The MgO layers have been deposited by electron beam evaporation method, where the $O_2$ partial pressures have been varied as 0, $5.2{\times}10^{-5}$ torr, $1.0{\times}10^{-4}$ torr, and $4.1{\times}10^{-4}$ torr, in this experiment. It is noted that work function that is energy gap between surface and first defect level of MgO layer has the lowest value for the highest O2 partial pressure of $4.1^{\ast}10^{-4}$ Torr.

  • PDF

Fault Analysis of Semiconductor Device (반도체 장치의 결함해석)

  • Park, S.J.;Choi, S.B.;Oh, C.S.
    • Journal of Energy Engineering
    • /
    • v.25 no.1
    • /
    • pp.192-197
    • /
    • 2016
  • We have surveyed on technical method of fault analysis of semiconductor device. Fault analysis of semiconductor should first be found the places of fault spots. For this process they are generally used the testers; EB(emission beam tester), EM(emission microscope), OBIRCH(optical beam induced resistance change method) and LVP(laser voltage probing) etc. Therefore we have described about physical interpretation and technical method in using scanning electron microscope, transmission electron microscope, focused ion beam tester and Nano prober.

Using Electron-beam Resists as Ion Milling Mask for Fabrication of Spin Transfer Devices

  • Nguyen Hoang Yen Thi;Yi, Hyun-Jung;Shin, Kyung-Ho
    • Journal of Magnetics
    • /
    • v.12 no.1
    • /
    • pp.12-16
    • /
    • 2007
  • Magnetic excitation and reversal by a spin polarized current via spin transfer have been a central research topic in spintronics due to its application potential. Special techniques are required to fabricate nano-scale magnetic layers in which the effect can be observed and studied. This work discusses the possibility of using electron-beam resists, the nano-scale patterning media, as ion milling mask in a subtractive fabrication method. The possibility is demonstrated by two resists, one positive tone, the ZEP 520A, and one negative tone, the ma-N2403. The advantage and the key points for success of this process will be also addressed.