ZONE GRID ASSEMBLY PARTICULARLY FOR HIGH RESOLUTION RADIOACTIVITY DISTRIBUTION DETECTION SYSTEMS

A zone grid assembly for flagging specified X,Y memory locations for accumulated data analysis and for presentation on a display in connection with a radioactivity distribution detection system. The zone grid assembly includes a printed circuit board formed with a plurality of holes and a pair of arcuate conductors disposed diametrically opposite one another about the periphery of each hole. A plurality of electrically conducting and magnetically responsive balls are slidably received within the zone grid assembly in such a manner that each ball is adapted for engagement and disengagement with one pair of conductors. A magnetic stylus held in spaced relationship with the zone grid assembly operates to actuate a ball in registration therewith into engagement with its associated pair of conductors. In consequence, the engaged pair of conductors are electrically connected and a signal denoting a particular X,Y position in the zone grid assembly is applied to the memory for processing, each X,Y grid position corresponding to an X,Y address location in the memory.