The present invention relates to a gamma-electric cell for producing a high-output voltage from a source of radiation wherein the gamma-electric cell includes a central collector constructed of a dense metal and with the central collector encapsulated within an outer layer of dielectric material. A further conductive layer is then disposed on or within the dielectric material so as to provide for a high voltage output between the conductive layer and the central collector upon the reception of radiation by the gamma-electric cell. The invention also includes the use of a plurality of collectors radiating from the central collector throughout the dielectric material so as to increase the collection area and thereby increase the current and/or output voltage. Other aspects of the invention are directed to the method of producing a high voltage output gammaelectric cell by encapsulation techniques using a dielectric material which is castable and curable so as to provide for an intimate contact between the collectors and the dielectric material which surrounds and encapsulates the collectors. Other aspects of the method of encapsulation of the present invention include the use of specific dielectric materials and also the elimination of trapped gases within the dielectric material.