1990 Fiscal Year Final Research Report Summary
Development of X-Ray Camera Tubes with Avalanche-Amplification
| Project/Area Number |
01880015
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | National Laboratory for High Energy Physics (KEK) |
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Principal Investigator |
CHIKAWA J. KEK, 放射光実験施設, 教授 (20175459)
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| Co-Investigator(Kenkyū-buntansha) |
佐藤 史郎 日本放送協会, 放送技術研究所, 研究員
平井 忠明 日立製作所, 中央研究所, 主任研究員
設楽 圭一 日本放送協会, 放送技術研究所, 主任研究員
河村 達郎 日本放送協会, 放送技術研究所, 部長
HIRAI T. Hitachi Central Research Lab.
SATO F. NHK Research Laboratories
KAWAMURA T. NHK Research Laboratories
SHIDARA K. NHK Research Laboratories
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| Project Period (FY) |
1989 – 1990
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| Keywords | Amorphous selenium photoconductors / X-ray camera tube / Avalanche-amplification |
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| Research Abstract |
High-resolution and high-sensitivity X-ray television cameras are required for X-ray real-time observation by imaging techniques such as X-ray microscopy and topography. In the present project, we developed an X-ray sensing camera tube with avalanche-amplification for the first time which was able to image individual X-ray photons with a resolution of 6 mum.
X-ray Saticon camera tubes having amorphous selenium photoconductive layers have been widely used for X-ray topography. Their sensitivity was so low that detection of individual X-ray photons was impossible ; when 10 photons with a photon energy of 10 keV were received per picture element per frame (1/30 sec), the signal was nearly equivalent to the noise level of video amplifiers. In comparison with this conventional camera tubes, the camera tube developed in this project has a 100 times higher sensitivity and is sensitive enough to detect one X-ray photon by the avalanche-amplification which was achieved by applying high electric field on the amorphous selenium photoconductive layer. It was found that the signal height of individual photons is proportional to their photon energy if they are absorbed near the entrance surface of the conductive layer.
Therefore, energy-resolved, high-resolution two-dimensional detector may be realized in the future by fabricating two layers absorbing photons and making avalanche-amplification separately.
To demonstrate its sensitivity, a real-time observation has been made for epitaxial growth from a thin amorphous silicon film (thickness of 300 nm) ; X-ray topographs for a very weak diffraction from such a thin film was imaged clearly on a TV monitor by using a conventional rotating-target X-ray generator operated at a tube voltage of 50 kV and tube current of 300 mA. This high sensitivity indicates a possibility of the time-resolved imaging that one topographic image can be formed by one x-ray pulse (-100 ps) from a synchrotron radiation source.
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