Low-Temperature Alignment of Radioactive Nuclei

Low-temperature research at the .L·Ta tional Bureau of Standards has succeeded in aligning the nuclei of three radioactive elements-- ceri~l39 , cerimn-141, and neodJrodlmrl47o These results were achieved by cooling samples of the t :b..ree materials to within a fe1r1 thousandths of a degree of absolute zero. At such temperatures the effects of thermal agitation becollle so small that atomic nuclei can line up in a given direction within t he crystal lattice. A corresponding directional effect can then be observed in t he errdtted radiation.