| 摘要 |
PURPOSE:To perform sufficiently stable operation even in the presence of a magnetic field by applying the anode of a gass-filled phototube with a voltage higher than the grid, and connecting selectively both voltages which are higher and lower than the grid voltage to the photoelectric surface. CONSTITUTION:A net anode 8, grid 9, plane type photoelectric surface 10 are arranged successively in a sealed container 6 from the side of a window 7 in parallel. Then, a 1.5V power source E1 is connected to the anode 8, and a -20V power source E2 is connected to the grid 9. Further, a -400V power source E3 is connected to the photoelectric surface 10 through a changeover switch 14. Light to be measured which is incident to the phototube is transmitted through the anode 8 and grid 9 to strike the photoelectric surface 10, emitting photoelectrons. At this time, the electrons are multiplied and a large charge is taken out of the anode 8. On the other hand, when the process of this multiplication is completed, the switch 14 is changed over to the ground side. |
