LAMINATED CHANNEL PLATE ELECTRON MULTIPLIER

摘要

14 In order to improve the gain of the input dynode of a laminated channel plate electron multiplier an apertured metal sheet is disposed at a small distance (30 um) from the outer surface of the input dynode and is used to provide a small negative field for turning back stray secondary electrons which have sufficient energy to follow trajectories across the input side of the input dynode. More particularly in order to improve the contrast of an image to be produced the area between the apertures of the input dynode are masked by a material having a secondary electron emission coefficient of less than 2, which material is provided on the outer surface of the apertured metal sheet, the metal sheet being spaced from the input dynode by the insulating material. A potential of the order of -10 v relative to the input dynode is applied to the apertured metal sheet. By masking the flat areas of the input dynode, the secondary electrons to be turned back are generally those from the part of the wall of the dynode furthest from the influence of the second dynode.