Avalanche counter and encoder system for counting and mapping radioactive specimens

A counter for detecting radioactive sources on a test specimen;

• the counter comprising:
• an electrically conductive planar window,
• a dielectric layer having a semiconductive surface parallel to and spaced from said window to form a chamber between said window and said semiconductive surface,
• means for sealing said chamber,
• a gas mixture of selected constituent gases contained within said chamber, and
• means for applying an electric field of selected magnitude across said chamber,
• said window being in a state of radial tension that may be selectively varied for assuring substantial flatness thereof.

An encoder system for defining the relative position of discrete electrical charge currents, the system comprising:

• a plurality of geometrically arrayed electrically conductive elements arranged symmetrically on a common planar surface.
• a matrix of conducting wires arranged in substantially equal pluralities of rows and columns, each such row being associated with a selected plurality of elements and each such column being associated with a selected plurality of elements whereby a selected row and column define one and only one element,
• a plurality of charge sensitive integrating amplifiers, one such amplifier being connected to each row, respectively, and one such amplifier being connected to each column, respectively,
• means for coupling a discrete electrical charge current only to those elements within relative proximity to said discrete current,
• means for coupling each said element to a row wire and to a column wire which are electrically isolated from each other whereby a preselected fraction of coupled charge current is transferred to each wire defining an element, the amplitude of the respective transferred charge fraction depending upon the location of the charge current relative to the element.