A radiation detector system and method that significantly reduces the cost of conventionally constructed radiation detectors is disclosed. The disclosed system generally comprises an injection molded detector body incorporating plastic material with embedded feed-thrus that are encapsulated within the detector body. This detector body is mated to a detector window assembly using a gasket or other means of sealing to inhibit gas leakage. The mating methodology between the detector body and the detector window assembly is by means of plastic snap-on tabs in these structures that permit semi-permanent mating while also allowing the structures to be easily disassembled for repair and maintenance. The present invention system/method permits a significant hardware cost reduction as compared to conventional prior art radiation detector construction methodologies.