SECOND  GENERATION  PASSIVE  VIEWERS.

The second generation passive viewers avoided the complexity of the cascade geometry by using a microchanneled tube where the secondary electron multiplication obtained from within one diode stage was of the same order of magnitude as the intensificaton obtained in three stages of the cascade tube. The diode contained a honeycomb or matrix of small glass tubes each of which accepted an element or dot of the spatial signal and multiplied this elemental signal by secondary emission from the walls of the tube. By proper choice of conductivity for the glass and application of a steady accelerating potential along the axis of the matrix, an image intensification was obtained in a short matrix length. When the matrix was incorporated into an electrostatically focussed tube, this proximity focussed tube gave a tube of very short axial dimensions.