| 摘要 |
PURPOSE:To obtain a photomultiplier tube with little fluctuation or the signal current from an anode electrode and not liable to the change of the terrestrial magnetism by curving the electron emitting section of the first-stage dynode in the same direction and allowing it to intersect the tube axis at an acute angle. CONSTITUTION:When a light spot is fed to scan each position of a photoelectric cathode 4, the photoelectrons from the cathode 4 are focused by a focusing electrode 8 respectively and fed to the electron emitting section 20 of the first- stage dynode 9 on the axial path along a funnel-shaped faucet 18-2. The emitted secondary electrons are multiplied by the box-shaped second-stage dynode 10-eighth-stage dynode 16 and extracted by an anode electrode 17. Portions 20a, 20b of the emitting section 20 are curved in the same direction together, the surface of the portion 20b has an acute angle to the tube axis B-B', thus the secondary electrons of each portion are reliably fed to the second-stage dynode 10. The uniform signal current not depending on the incident position of photoelectrons to the emitting section can be thereby extracted from the anode electrode, and this photomultiplier tube is not liable to the effect of the terrestrial magnetism.
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