tie Electronic tube develorments Riper Radio Corporation of Anerica for deveiorment of” tubes has been extended. F. The contract with the special puryose electronic Although the prototype tubes so far developed do not fully meet Cormission requirezents, significant progress has been made during the year in developing two types of photocultiplier tubes and a pulse height selector cathode ray tube. These tubes will achieve increased sensitivity, and will be able to amplify ebout a billion tines the original photo electronic response to the radiation being measured. These improvements will make possible experiments and physical meesurements on nuclear properties which have heretofore been very difficult to * pee argctee perform. (End of ®B6iieROSED section.) Air radon measurements (UNCLASSIFIED). DOE ARCHIVES In cooperation with the U. S. Public Health Service, AEC is measuring radon contemination of the air in Coloredo-Utah uranium mines. Semples taken at the mines formerly had to be sent:to one of three distant laboratories equipped to analyze them. The use of a recently developed portable unit permits analysis of air radon samples within the mine itself within 30 minutes. seem oe UNCLASSIFIED section.) (End of