超高速X線CTスキャナシステムの開発 : 気液二相流ボイド分布変動計測への適用  [in Japanese] Development of an Ultra-fast X-ray Computed Tomography Scanner System : Application for Measurement of Instantaneous Void Distribution of Gas-Liquid Two-Phase Flow  [in Japanese]

An ultra-fast X-ray computed tomography (CT) scanner has been developed. This scanner overcomes problems that occur in a transient or unsettled state, which make the conventional CT scanner inappropriate. To reduce the scanning time, this X ray CT system uses electronic switching of electron beams for X-ray generation instead of the mechanical motion adopted by conventional CT scanners. The mechanical motion is a major obstacle to improve scanning speed. A prototype system with a scanning time of 3.6 milliseconds was initially developed and confirmed to measure the dynamic events of two-phase flow. However, an increased scanning speed is generally required for practical use in the thermalhydraulics research field. Therefore, an advanced type which can operate under the scanning time of 0.5 milliseconds and can measure two-phase flow with a velocity up to 4〜5 m/s was developed.