Hitachi, Ltd.

Hitachi Medical Corporation

Tsuneyuki Kanai

Hiromichi Yamada

Makoto Sato

Ichiro Miura

Minoru Yoshida

Takaaki Suzuki

Tomoichi Kamo

Tadahiko Miyoshi

Shinpei Matsuda

Kunihiro Maeda

Akira Yoshinari

Kazutoshi Higashiyama

Hideyo Kodama

Yoshimi Yanai

Akira Okayama

Takaaki Kobiki

Teruo Kumagai

Atsuko Soeta

An oxide phosphor includes an oxide consisting of at least Gd, Ce, Al, Ga, and O, and has the crystal structure of a garnet structure, the atomic ratio (Gd+Ce)/(Al+Ga+Gd+Ce) of which is more than 0.375 and 0.44 or less, and the atomic ratio Ce/(Ce+Gd) of which is 0.0005 or more and 0.02 or less. This oxide phosphor reduces composition misalignment occurring during sintering, being a drawback of a phosphor having (GdCe)AlGaOcomposition, and has a property of extremely small afterglow and high luminescence efficiency. By using this oxide phosphor as a scintillator of a radiation detector having a light detector, the radiation detector with low afterglow and high output can be obtained. Further, by applying this radiation detector to an X-ray CT apparatus, a tomogram with high resolution and high quality can be obtained.

Oxide phosphor and radiation detector using it, and X-ray CT device

Phosphor, radiation detector containing the same, and X-ray CT apparatus

A method of producing a high-temperature oxide superconducting material, which comprises the steps of (a) preparing a material corresponding to an oxide superconductor of the perovskite type structure consisting essentially of a first member selected from the group consisting yttrium, lanthanoids, thallium and bismuth; at least one alkaline earth metal; copper; and oxygen and (b) heating the material in the presence of an alkali metal selected from the group consisting of potassium, sodium, rubidium and cesium to a temperature around the melting point of the alkali metal or to a higher temperature for a time sufficient to effect grain growth in the superconductor material, thereby to produce the superconductor containing the alkali metal in an amount not larger than 4 mole % based on the first member.

Oxide high-temperature superconducting material, method of preparing

There is obtained, by mixing oxide raw material powders, compacting the mixture and sintering the compact, a silicon nitride sintered body mainly composed of silicon nitride and having a grain boundary phase wherein crystals represented by Yb.sub.2 Si.sub.2 O.sub.7 and a Zr.sub.3 Yb.sub.4 O.sub.12 are present in the grain boundary phase and molar ratio ZrO.sub.2 /Yb.sub.2 O.sub.3 in terms of ZrO.sub.2 and Yb.sub.2 O.sub.3 is 2/98 to 75/25 and the total amount of ZrO.sub.2 and Yb.sub.2 O.sub.3 is 1-40% by weight of the sintered body.

Silicon nitride sintered body and method for producing same

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Hitachi, Japan

Tsuneyuki Kanai