| 摘要 |
PURPOSE:To improve an incidence efficiency into a photomultiplier and increase the resolution of a secondary electron image by positively converging the emission of a scintillator using a lens system. CONSTITUTION:The light appearing within the range of an angle alpha from one point (a) on the edge of a scintillator 1 passes through the whole surface of a lens L1 and is focussed on the point (b) on a lens L2. When the lens L2 is not provided, the ray of light that starts from the point (a), passes through the edge (c) of the lens L1, and arrives at the point (b) cannot be incident on a lens 3. Since the lens L2 forms the image coming from the lens L1 on the lens L3, the ray of light passing a-c-b is directed to the point (d) of the lens L3. Since the whole light flux that is incident on the lens L1 from the scientillator 1 passes through the lens L3 and the light passing through the lens L3 forms the image of the scintillator on a photosensitive surface 4, the whole light flux of the scinitillator that is incident on the lens 1 can be incident on the photosensitive surface 4. Although the image of the scintillator 1 projected through the lens 1 is size- to-size, the image on the photosensitive surface 4 made by the lens 3 is a reduced image depending upon the size of the photosensitive surface. |
