If the CSI family of television shows has blunted your appetite for impossibly omniscient crime scene analysis, consider the real, and very serious, science of nuclear forensics. If someone flouts the ban on nuclear weapons testing, we want to know as much about it as possible. And the resources backing that effort are substantial.

Seismic waves betray the occurrence of underground tests, and air samples grabbed soon afterward can contain the radioactive proof. But both are transient, and even radioactivity at the site of the explosion can fade too quickly to be of much use. A group of researchers at Los Alamos National Laboratory have demonstrated a new technique than can reveal the potency of the bomb from the debris—even decades after the fact.