The optical fibers of a VULCAN detector module. The fibers transmit the light signals created by captured neutrons to photo multiplier tubes where the signals are amplified and then sent to a data acquisition system. One of the newest and most popular instruments at the SNS is the VULCAN diffractometer. The reasons behind VULCAN's popularity are similar to those that make the SNS so attractive: it is new, and it has unusual capabilities. VULCAN was built to take measurements on engineering materials under stress. VULCAN is capable of seeing inside the material and making three dimensional maps of the distance between atoms in critical sections. Scientists can look at these maps and determine if the atoms are being squeezed together or pulled apart - signs of stress and strain in the materials. The Spallation Neutron Source (SNS) is an accelerator-based neutron source facility that provides the most intense pulsed neutron beams in the world for scientific research and industrial development. Each year, this facility hosts hundreds of researchers from universities, national laboratories, and industry, who conduct basic and applied research and technology development using neutrons.