Neutron vision

From New Orleans, at a meeting of the American Physical Society

BEAT SUPERMAN. A neutron beam imaged these Asian lilies inside a lead cask, where X rays cannot reach. Neutrons could be used to detect radioactive materials in cargo. Daniel Hussey/NIST

A new technology for measuring neutrons might help detect smuggled radioactive materials.

A common type of neutron detector uses a container filled with helium-3, a light isotope that readily reacts with neutrons.