Midget portable x-ray unit sits in the hand of Lois Mellquist, right, a nurse at Argonne Lab. Betty Van Dolah, technologist, stands overshadowed by conventional x-ray unit
Radioactive Thulium for X-Rays Radioactive power from thulium makes Argonne x-ray unit a potential for medical and industrial use A
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have to b e strong a n d would have to be replaced after one year. For check ing density of fluids in pipe, source would probably be suitable for use u p to two years. Penetration of thulium varies b u t is comparable to that of a 90-kilovolt-peak x-ray unit. (This gives lower intensity than conventional x-ray unit.) Argonne says limitations of t h e machine are not clear as y e t . The Argonne development was di rected b y Samuel Untermeyer. Thu lium was procured from AEC's Ames Laboratory at Iowa State College where F r a n k Spedding h a s pioneered in the separation of rare earth metals. Use of thulium as an x-ray source was first suggested b y British scientists who have developed a similar b u t less powerful instrument. T h e Argonne in strument contains a thulium source several hundred times more powerful than the British units. This greater power makes the Argonne unit poten tially useful for medical a n d industrial purposes, says developer.
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x-ray unit, developed b y scien tists at Argonne National Laboratory, provides rays which are comparable in energy to a 100,000 volt x-ray machine. Active component of the instrument is a tiny particle (one-fifth gram) of thulium-170 which has been made radioactive in a heavy water nuclear reactor at Arco, Idaho. Like some of the other radioactive isotopes, such as cesium-137, thulium gives off soft x-rays in addition to gamma rays. T h e thulium unit is not expected to replace conventional x-ray equipment b u t may prove useful in a number of special applications. The Argonne group has used t h e unit to determine density of a steam-water mixture inside a piping system. In operation, thulium is mounted in a source holder and shield equipped with a shutter mechanism so that x-ray photographs m a y be made. Shutter is operated by a standard photographic cable release. T h e entire x-ray unit weighs less t h a n 10 pounds and does not require an electrical power supply. Total cost of the first model, says Argonne, exclusive of irradiation charges, was $ 4 0 . Thulium has a half life of 129 days, b u t Argonne says source in unit is use ful for one to t w o years depending on strength required for application. For x-raying hands or feet, source would V O L U M E
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U. S. Annual Loss by Deterioration Exceeds $12 Billion The annual loss b y deterioration of all kinds of materials (exclusive of drugs and foodstuffs) in the United States is more than $12 billion, accord ing to the Prevention of Deterioration .
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Center. T h e center is a service facility for t h e Department of Defense, Divi sion of Chemistry and Chemical Tech nology, National Academy of Sciences —National Research Council. T h e center says that most deteriora tion problems may b e explained in terms of clear-cut chemical, physical, and biological criteria. Intensive prac tical application of scientific principles toward preserving manufactured goods has now come to be known as deteri oration prevention, a sort of science in itself. A comparatively new develop ment, it stems from the experience of the Armed Forces in the early years of World W a r II, when deterioration of service equipment became a serious problem in military operations. A booklet describing operations of the center is available from the center at National Academy of SciencesNational Research Council, 2101 Con stitution Ave., Washington 25, D . C. *v ^r *w • Automatic hazard analyzer, built by t h e nuclear physics section of Ar mour Research Foundation, provides a 24-hour-a-day check for airborne radio activity. Analyzer samples air continu ously, presenting information on air borne radiation on four dials and also on a moving chart for a permanent rec ord. It sounds a warning horn if t h e radiation level gets too high for safety. Unit also has two radiation counters for monitoring surface contamination. • Fogged photographic film could have been t h e work of radioactive dust particles, according to dustfall studies in Chicago b y Armour Research Foun dation. Walter C. McCrone, chemist at t h e foundation, says radioactivity (about 100 times the average level) in Chicago during March was strong enough to fog film if particles came in direct contact with it. • Optical cement which is said to with stand extreme temperature variations and mechanical shock has been devel oped by the Navy research department. T h e cement, a plastic obtained from cellulose caprate, is easily made, simple to apply, virtually colorless, and has fewer foreign particles than any other cement yet developed, according to Navy researchers. It also is highly re sistant to fungus. • High temperature strength stainless alloys have been developed for the Navy Bureau of Aeronautics by Cornell Aeronautical Laboratory, Buffalo, Ν . Υ. Three modified stainless alloys which demonstrate twice the conventional strength at 1200° to 1500° F. were m a d e in a program aimed at replacing strategic alloys needed in jet aircraft service. Laboratory says the new alloys need further investigation before their use can be recommended. 1769
