| 摘要 |
PURPOSE:To reconstitute a tomographic image with high resolution even when the size of samples varies by making the distance between a radiation source and rotational center variable so that the measuring extent can become an irreducible minimum for completely encircling the sample. CONSTITUTION:A gantry section 2 is supported rotatably around a center O and rotated by a motor 4. A frame-like movable member 8 is supported by guide members 10 and 12 fixed to the gantry section 2 so that the member 8 can make linear movement along the gantry section 2. A gear 18 is engaged with a rack 16 fitted to the member 8 and, when the gear 18 is driven by a motor 14, the member 8 moves in the direction shown by the arrow 20. A radiation source 24 is fitted to the member 8 and a detector 26 is provided on the opposite side of the center O. The member 8 is moved by actuating the motor 14 so as to make the measuring extent sufficient to encircle a sample 22 completely in accordance with the size of the sample 22 provided at the position of the center O. When the radiation source 24 is positioned, the measurement is performed by detecting the beams emitted from the source 24 with the detecting section 26 while the gantry section 2 is rotated. |
