Spallation Neutron Source (SNS)

Aerial of the Spallation Neutron Source showing the Guest House, JINS, CLO, CNMS, and target building.

The SNS is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in the world.
Oak Ridge, Tennessee Location
2006 Start of Operations
577 (FY 2022) Number of Users


The Spallation Neutron Source (SNS), at Oak Ridge National Laboratory, which began operation in 2006, is presently the most powerful accelerator-driven neutron source in the world, operating at a power of 1 MW.  Sub-microsecond 60 Hz proton pulses from the accelerator complex impinge on a liquid-mercury target, generating pulses of neutrons that feed 19 operating instruments, and space for a maximum of 5 more. The number of unique users served has grown rapidly, reaching 900 in 2014. Beam time is oversubscribed by factors of 2 to 5, reflecting both the demand for this facility and the overall lack of capacity in terms of neutron instruments in the U.S.


Thermal neutrons are particularly well suited for measuring the positions as well as the fluctuations in the positions of atoms, the structure of atomic magnetic moments in solids, and magnetic excitations.  Such studies lead to understanding phenomena such as correlated electron effects, magnetic order, and superconductivity in a variety of materials.