[In Depth] Researchers rise to challenge of replacing helium-3
U.S. researchers have finally overcome a little-known legacy of the 11 September 2001 terrorist attacks: a dire shortage of helium-3 (He-3). The rare isotope has unique properties that make it invaluable for applications from cryogenics to detecting hidden nuclear bomb material. But in 2008, experts feared that the U.S. stockpile, managed by the Department of Energy's (DOE's) Isotope Program, would run out as early as 2010, as terrorism fears drove up demand for detectors of nuclear material. DOE curtailed He-3 sales while it and other agencies raced to find He-3 alternatives. Observers hail the effort as a remarkable success. A dozen alternatives are in the pipeline or already on the market, and the He-3 stockpile is out of danger. DOE's reserves will top 160,000 liters by 2040, according to a new projection the department provided to Science. Author: Richard Stone