• 제목/요약/키워드: synchrotron X-ray

검색결과 264건 처리시간 0.029초

형광 X선 CT에서 촬상 시간의 단축화 알고리즘 (Algorithm to Shorten Imaging Time in Fluorescent X-ray Computed Tomogrpahy)

  • 정남채
    • 융합신호처리학회논문지
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    • 제2권4호
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    • pp.46-52
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    • 2001
  • 방사광을 이용한 형강 X선 CT 이미징의 고속화를 위한 촬상 시스템과 처리 알고리즘을 검토하였다. 본 논문에서 사용된 촬상시스템은 고계수율 영역에서 안정된 동작을 한 전자 시스템으로 불감시간이 약 6%로 감소되고 계측시간의 경우도 1 점 당 3초로 단축되었다. 또한 재구성 알고리즘의 효율화를 증명하였고, 메모리와 계산량을 약 1/100로 감소시켰다. 물리적 phantom으로 그 정량성을 확인하였고, 시험관내의 갑상선의 화상으로부터 요드 분포를 추정하였다. 이러한 결과는 생체내에서 형광 X선 CT 계측의 실현 가능성을 보여준 것이다.

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PREFERRED ORIENTATION OF TIN FILM STUDIED BT A REAL TIME SYNCHROTRON X-RAY SCATTERING

  • Je, J.H.;Noh, D.Y.
    • 한국표면공학회지
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    • 제29권5호
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    • pp.399-406
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    • 1996
  • The orientational cross-over phenomena in an RF sputtering growth of TiN films were studied in an in-situ, real-time synchrotron x-ray scattering experiment. For the films grown with pure Ar sputtering gas, the cross-over from the more strained (002)-oriented grains to the less strained (111)-oriented grains occurred as the film thickness was increased. As the sputtering power was increased, the cross-over thickness, at which the growth orientation changes from the <002> to the <111> direction, was decreased. The addition of $N_2$ besides Ar as sputtering gas suppressed the cross-over, and consequently resulted in the (002) preferred orientation without exhibiting the cross-over. We attribute the observed cross-over phenomena to the competition between the surface and the strain energy. The x-ray powder diffraction, the x-ray reflectivity, and the ex-situ AFM surface topology study consistently suggest that the microscopic growth front was in fact always the (002) planes. In the initial stage of growth, the (002) planes were aligned to the substrate surface to minimize the surface energy. At later stages, however, the (002) growth front tilted away from the surface by about $60^{\circ}$ to relax the strain, which caused the cross-over of the preferred growth direction to the <111> direction.

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Real-time X-ray Scattering as a Nanostructure Probe for Organic Photovoltaic Thin Films

  • 이현휘;김효정;김장주
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.181-181
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    • 2013
  • Recently, nanostructure and the molecular orientation of organic thin films have been largely paid attention due to its importance in organic electronics such as organic thin film transistors (OTFTs), organic light emitting diodes (OLEDs), and organic photovoltaics (OPVs). Among various methods, the diffraction and scattering techniques based on synchrotron x-rays have shown powerful results in organic thin film systems. In this work, we introduce the in-situ annealing system installed at PLS-II (Pohang Light Source II) for organic thin films by simultaneously conducting various x-ray scattering measurements of x-ray reflectivity, conventional x-ray scattering, grazing incidence wide angle x-ray scattering (GI-WAXS) and so on. Using the in-situ measurement, we could obtain real time variation of nanostructure as well as molecular orientation during thermal annealing in metal-phthalocyanine thin films. The variation of surface and interface also could be simultaneously investigated by the x-ray reflectivity measurement.

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Preliminary Radiological Considerations for X-ray Free Electron Laser Project at PAL

  • Lee, Hee-Seock;Hong, Suk-Mo;Kim, Min-Ho
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 2004년도 추계학술발표회 발표논문집
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    • pp.1190-1191
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    • 2004
  • New $4^{th}$ generation synchrotron facility, XFEL, is almost similar to previous $3^{rd}$ generation synchrotron facility in the view of radiological aspects and most important positions are a dump and synchrotron radiation beam line. In this paper, tile radiation protection solutions for them and undulator are suggested and discussed.

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Exploring Fine Structures of Photoactive Yellow Protein in Solution Using Wide-Angle X-ray Scattering

  • Kim, Tae-Kyu;Zuo, Xiaobing;Tiede, David M.;Ihee, Hyot-Cherl
    • Bulletin of the Korean Chemical Society
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    • 제25권11호
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    • pp.1676-1680
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    • 2004
  • We demonstrate that wide-angle X-ray scattering pattern from photoactive yellow protein (PYP) in solution using a high flux third generation synchrotron X-ray source reflects not only the overall structure, but also fine structures of the protein. X-ray scattering data from PYP in solution have been collected in q ranges from 0.02 ${\AA}^{-1}$ to 2.8 ${\AA}^{-1}$. These data are sensitive to the protein structure and consistent with the calculation based on known crystallographic atomic coordinates. Theoretical scattering patterns were also calculated for the intermediates during the photocycle of PYP to estimate the feasibility of time-resolved wide-angle X-ray scattering experiments on such proteins. These results demonstrate the possibility of using the wide-angle solution X-ray scattering as a quantitative monitor of photo-induced structural changes in PYP.