Million-volt industrial X-ray unit

THREE DEVELOPMENTS of co-ordinated research stand out as major factors in the General Electric Company´s noteworthy achievement of a 1,000-kv portable industrial X-ray equipment: (a) dichlordifluormethane (“Freon”) instead of air or oil as an electrical insulating medium; (b) a compact air-core resonance transformer; (c) a multisection X-ray tube small enough to be accommodated within the core space of the transformer. The result of the development and combination of these and other elements is the 1,500-pound self-contained million-volt equipment shown on the front cover and these pages. An extended investigation of the electrical insulating properties of many gases and chemical vapors disclosed that some of them not only were far superior to air at equivalent pressures, but also provided better insulation than oil and were much lighter in weight. One of these special gases which is readily available and which has good physical and chemical properties is dichlordifluormethane (Freon). It has 2.5 times the insulating strength of air at equivalent pressures.