• Title/Summary/Keyword: Microfocus x-ray tube

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Microfocus X-ray CT Analysis of Shrinking Direction in Resin Composite.

  • Inai, N.;Katahira, N.;Hashimoto, K.;Tagami, J.;Hirakimoto, A.;Marshall, S.J.;Marshall. G.W.
    • Proceedings of the KACD Conference
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    • 2001.11a
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    • pp.559.1-559
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    • 2001
  • The aim of the study was to determine the direction and the rate of polymerization shrinkage of light-cured resin composite. Materials and Methods: A microfocus x-ray CT(computed tomography) instrument (SMX-255CT, Shimadzu Co., Kyoto, Japan) was used to analyze and characterize the pre-and post-gel phases. A microfocus x-ray tube was used to enable a focus dimension of 4 microns.(omitted)

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X-RAY Inspection for PCB/SMT & Electronics Components Latest Development

  • Maur Friendhelm W.
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2004.02a
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    • pp.17-25
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    • 2004
  • During the past few years, advances have been made in both in X-ray tube and detector technologies. The field of microfocus radioscopy has been established as an important testing process and has expanded into many new industrial applications that require quality control or process optimization. The first nanofocus and multifocus X-ray systems have become available with a focal spot of .5 micron. In the existing range of microfocus X-ray tubes, further improvements have been achieved as well, such as increased long term stability of intensity position constancy. Software, image processing and manipulation techniques have all progressed as well, allowing X-ray to become a formidable non-destructive inspection method for manufacturers in virtually every industry, especially those involved with Electronic Packaging and SMT.

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Design of X-ray Target for a CNT-based High-brightness Microfocus X-ray Tube (탄소나노튜브를 이용한 고휘도 마이크로빔 X-선원 발생부 설계)

  • Ihsan Aamir;Kim Seon Kyu;Heo Seong Hwan;Cho Sung Oh
    • Journal of the Korean Vacuum Society
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    • v.15 no.1
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    • pp.103-109
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    • 2006
  • A target for a high-brightness microfocus x-ray tube, which is based on carbon nanotubes (CNT) as electron source, is designed. The x-ray tube has the following specifications: brightness of $1\times10^{11}phs/s.mm^2. mrad^2$, spot size $\~5{\mu}m$, and average x-ray energy of $20\~40 keV$. In order to meet the specifications, the design parameters of the target, such as configuration, material, thickness of the target as well as the required beam current, were optimized using computer code MCNPX. The design parameters were determined from the calculation of both x-ray spectrum and intensity distribution for a transmission type configuration. For the thin transmission type target to withstand vacuum pressure and localized thermal loading, the structural stability and temperature distribution were also considered. The material of the target was selected as molybdenum(Mo) and the optimized thickness was $7.2{\mu}m$ to be backed by $150{\mu}m$ beryllium (Be). In addition, the calculations revealed that the maximum temperature of the transmission target can be maintained within the limits of stable operation.

Development of an electron source using carbon nanotube field emittes for a high-brightness X-ray tube (탄소나노튜브를 이용한 고휘도 X-선원용 전자빔원 개발)

  • Kim, Seon-Kyu;Heo, Sung-Hwan;Cho, Sung-Oh
    • Journal of the Korean Vacuum Society
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    • v.14 no.4
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    • pp.252-257
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    • 2005
  • A high-brightness electron beam source for a microfocus X-ray tube has been fabricated using a carbon-nanotube (CNT) field emitter. The electron source consists of cathode that includes a CNT field emitter, a beam-extracting grid, and an anode that accelerates that electron beam. The microfocus X-ray tube requires an electron beam with the diameter of less than 5 $\mu$m and beam current of higher than 30 $\mu$A at the position of the X-ray target. To satisfy the requirements, the geometries of the field emitter tips and the electrodes of the gun was optimized by calculating the electron trajectories and beam spatial profile with EGUN code. The CNT tips were fabricated with successive steps: a tungsten wire with the diameter of 200 $\mu$m was chemically etched and was subsequently coated with CNTs by chemical vapor deposition. The experiments of electron emission at the fabricated CNT tips were performed. The design characteristics and basic experimental results of the electron source are reported.

Experimental Study for Phase-contrast X-ray Imaging Based on a Single Antiscatter Grid and a Polychromatic X-ray Source (단일 비산란 그리드 및 다색광 x-선원 기반 위상대조 x-선 영상화 실험 연구)

  • Park, Yeonok;Cho, Hyosung;Lim, Hyunwoo;Je, Uikyu;Park, Chulkyu;Cho, Heemoon;Kim, Kyuseok;Kim, Guna;Park, Soyoung
    • Progress in Medical Physics
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    • v.26 no.4
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    • pp.215-222
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    • 2015
  • In this work, we performed a proof-of-concept experiment for phase-contrast x-ray imaging (PCXI) based on a single antiscatter grid and a polychromatic x-ray source. We established a table-top setup which consists of a focused-linear grid having a strip density of 200 lines/inch, a microfocus x-ray tube having a focal-spot size of about $5{\mu}m$, and a CMOS-type flat-panel detector having a pixel size of $48{\mu}m$. By using our prototype PCXI system and the Fourier demodulation technique, we successfully obtained attenuation, scattering, and differential phase-contrast images of improved visibility from the raw images of several selected samples at x-ray tube conditions of $90kV_p$ and 0.1 mAs. Further, fusion image (e.g., the attenuation+the scattering) may have an advantage in displaying details of the sample's structures that are not clearly visible in the conventional attenuation image. Our experimental results indicate that single-grid-based approach seems a useful method for PCXI with great simplicity and minimal requirements on the setup alignment.

THREE DIMENSIONAL RECONSTRUCTION OF TEETH USING X-RAY MICROTOMOGRAPHY (X-ray microtomography를 이용한 치아의 3차원 재구성)

  • Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.28 no.6
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    • pp.485-490
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    • 2003
  • Complete understanding of the exterior and interior structure of the tooth would be prerequisite to the successful clinical results, especially in the restorative and endodontic treatment. Although three-dimensional reconstruction method using x-ray microtomography could not be used in clinical cases, it may be the best way to reconstruct the morphologic characteristics of the tooth structure in detail without destructing the tooth itself. This study was done to three dimensionally reconstruct every teeth in the arch in order to increase the understanding about the endodontic treatment and to promote the effective restorative treatment by upgrading the knowledge of the tooth morphology. After placing tooth between the microfocus x-ray tube and the image intensifier to obtain two-dimensional images of each level. scanning was done under the condition of 80 keV, $100{\;}\mu\textrm{m}$, 16.8 magnification with the spot size of $8{\;}\mu\textrm{m}$. Cross-section pixel size of $16.28{\;}\mu\textrm{m}$ and 48.83 cross-section to cross-section distance were also used. From the results of this study, precise three dimensional reconstructed images of every teeth could be obtained. Furthermore, it was possible to see image that showed interested area only, for example. enamel portion only, pulp and dentin area without enamel structure, pulp only, combination image of enamel and pulp, etc. It was also possible to see transparent image without some part of tooth structure. This image might be used as a guide when restoring and preparing the full and partial crown by showing the positional and morphological relationship between the pulp and the outer tooth structure. Another profit may be related with the fact that it would promote the understanding of the interior structure by making observation of the auto-rotating image of AVI file from the various direction possible.