ORNL is responsible for the design and construction of the liquid mercury target. Because of the enormous amount of energy that the short, powerful pulses of the incoming 1-GeV proton beam will deposit in the spallation target, it was decided to use a liquid mercury target rather than a solid target such as tantalum or tungsten. The SNS will be the first scientific facility to use pure mercury as a target for a proton beam. The neutrons coming out of the target must be turned into low-energy neutrons suitable for research that is, they must be moderated to room temperature or colder. These moderators are located above and below the target.
Cold neutrons are especially useful for research on polymers and proteins.
The SNS is an inherently safe way to produce neutrons because the neutron production stops when the proton beam is turned off. It also produces few hazardous materials. To maximize the safety of the facility, the SNS will be designed to have many levels of containment to keep potentially hazardous material from getting into the environment. The final instrumentation will be determined by the user community through the SNS Instrument Oversight Committee. Two thermal moderators and two cold moderators will be used to service 18 beam lines, and a variety of instruments will be constructed on these beam lines.