| 摘要 |
PURPOSE:To achieve improved response speed and sensitivity by installing a mesh electrode facing a photoelectric screen consisting of a curved surface symmetrical relative to the axis and rapidly accelerating photo-electrons to reduce the extension of the photo-electron group becoming incident upon the first dynode. CONSTITUTION:A photomultiplier tube is constituted by arranging a photoelectric screen 2 consisting of a curved surface symmetrical relative to the axis, a mesh electrode 3, a focusing electrode 4 and an aperture electrode 5 in that order and installing an anode 14 and a secondary electron multiplier part consisting of first to eighth dynodes 6-13 in an airtight glass case 1 having a window 1a. A voltage of in the range between several hundreds and several kV is applied across the photoelectric screen 2 and the mesh electrode 3 to reduce the extension of a photo-electron group becoming incident upon the first dynode 6 after being emitted from an arbitrary point on the photoelectric screen 2 into a spot. Therefore, the efficiency of emitting secondary electrons is improved and any difference in the travelling hour of photo-electrons is prevented, thereby achieving improved time response. |
