Protection against nuclear or radiological attack has motivated the search for more definitive radiation detection and identification technologies. Detecting and distinguishing neutrons from gamma rays is the key to identifying nuclear substances such as uranium and plutonium and differentiating them from benign radioactive sources. Current detection devices typically employ commercial liquid scintillators, which are inexpensive and readily available but have low resolution and difficult deployment limitations owing to the toxicity, flammability and handling difficulties. Solution-Grown Crystals for High-Energy Neutron Detection made of stilbene constitute the best known scintillator material capable of definitively distinguishing neutrons from gamma rays. The new method could lead to widespread use of the new materials for large-volume and low-cost detectors that could aid in the protection of ports, stadiums, airport scanners, nuclear power plants and other facilities.