Grid Current and Grid Emission Studies in Thyratrons-the Trigger-Grid Thyratron

Grid emission leads to unstable control characteristics in thyratrons. Positive ion grid current during the afterglow results in delayed recovery of grid control. Both these drawbacks can be overcome by use of low values of grid resistors, but at the expense of input signal current sensitivity. The requirement for low grid resistance can be eliminated by assigning the firing function to a fine wire electrode known as the trigger grid. The other function of a conventional thyratron grid, which is to promote recovery of control, is assigned to another electrode known as the blocking grid. Since the latter electrode is connected to a bias supply through a low resistance, its emission and positive ion collection do not produce disturbing effects. Comparisons of an experimental trigger grid thyratron with its conventional prototype reveal many advantages of the former.