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.