本邦における第3世代放射光施設SPring-8では,高輝度,大強度,高エネルギーなどの特徴をもつX線ビームを用いて,生命科学から物質科学にいたる分野で放射光利用研究が実施されている. に対する要求も多彩であり,二次元電荷結合型,マイクロストリップガス検出器,一次元マイクロストリップゲルマニウム半導体検出器,位置敏感型電離箱などのが共同開発されている.本稿では,こうしたの研究開発の現状について報告する.

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我々は透過型電子顕微鏡に搭載するエネルギー分散型として、超伝導転移端温度センサー(TES)型の開発研究を展開している。本研究では、4ピクセル配置のTES型を試作した。個々のピクセルは、TESの全面を厚さ0.5μmのAu吸収体層が覆い、TESとの間に厚さ0.1μmのTa2O5絶縁層が挿入されている。選択した2ピクセルについてX線検出特性を測定した。

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Due to accidents of the nuclear power plants in Fukushima prefecture, a lot of radioisotopes were diffused into the environment. They adhered onto the surface of the X-ray detector (imaging plate; IP) and many black spots were seen on the medical images. The process to count them is important to evaluate the degree of contamination and/or removal. In this study, we aimed to develop a counting method for black spots. Based on the analysis of the medical images having black spots, we summarized that areas affected by the certain black spots were limited to the eight pixels surrounding the most intensive pixel. The newly developed counting method was applied to these nine pixels (3×3 pixels) and selection rules were based on the following two information: 1. differences between the digital value of the most intensive pixel and those of the surrounding eight pixels, and 2. total summation of the digital values in the nine pixels. The estimated image based on our method showed a good concordance with the original image. Therefore, we summarized that our counting method is a powerful tool for estimating numbers of black spots.

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Among newly developed X-ray detectors, multiwire proportional chambers are described with reference to the working principles and signal read-out techniques. The variable detection area, moderate position sensitivity and potential high count-rate capa-bility can be exploited in making an efficient data collection system in various diffraction experiments. References are also made to problems encountered in making synchrotron radiation detectors.

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A micro-computed tomography (micro-CT) system was developed using a 10-megapixel CCD camera for 3D biomedical imaging. The system consists of a beryllium window for X-ray incidence, a fluorescent screen, an optical mirror, high numerical aperture lenses and the CCD camera. X-rays are converted into a visible image in the screen which has a thickness of 10μm. The mirror deflects the luminescent light 90° to the lens system that focuses it on the camera. The X-ray field of view is 24-mm wide by 16-mm high (4, 024×2, 648 pixels); a pixel measures 6×6μm. A rabbit auricle specimen implanted with a carcinoma was fixed in formalin after a barium sulphate solution was injected into the blood vessels as a contrast agent. 3D images of the specimen were obtained by tomographic reconstruction, and small blood vessels induced by the tumor were seen.

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