Second Target Station Instrument Systems

The Second Target Station (STS) at Oak Ridge National Laboratory’s (ORNL) Spallation Neutron Source (SNS) will provide transformative new capabilities for discovery science, enabling breakthroughs in many areas of materials research and development, including polymers, quantum matter, biotechnologies, structural materials, and energy storage.

The STS Instrument Systems group will construct eight world-class instruments ready to transition to operations and begin commissioning by the end of the project. As discussed in the First Experiments: New Science Opportunities at the Spallation Neutron Source Second Target Station report, STS will provide unique capabilities for experiments that require:

  • Time-resolved measurements of kinetic processes and beyond-equilibrium matter
  • Simultaneous measurements of hierarchical architectures from the atomic scale to microns and beyond
  • Measuring small samples of newly discovered or synthesized materials
  • Exploring new frontiers in materials at extreme conditions

The STS will have capacity for 20 beamlines that will complement those at the SNS First Target Station (FTS) and the High Flux Isotope Reactor (HFIR).

The eight instruments selected to be constructed as part of the STS project are listed in alphabetical order below.

BWAVES, a broadband wide-angle velocity selector spectrometer, will simultaneously probe dynamic processes spanning 4.5 orders of magnitude in energy transfer, measuring continuous spectra that comprise both vibrational and relaxational excitations, from 0.01 meV to hundreds of meV. It will enable neutron scattering studies of dynamics in materials over the broadest possible range, especially complex biological, soft, and chemical systems characterized by dynamic processes spanning a wide range of time.

ORNL Contact: Eugene Mamontov (



CENTAUR, a small-/wide-angle scattering instrument, will be designed to provide best-in-class resolution, dynamic range, and unique spectroscopic capabilities. The instrument will fully leverage the STS source, state-of-the-art neutron optics, and detectors that enable simultaneous study of a wide range of length scales with high resolution, measuring smaller samples, and making time-resolved investigations of evolving structures in a wide range of scientific areas, such as soft matter, biology, material, geology, and quantum condensed matter.

ORNL Contact: Shuo Qian (



CHESSa direct geometry neutron spectrometer, will be designed to detect and analyze weak signals intrinsic to small cross-sections (e.g., small mass, small magnetic moments, neutron-absorbing materials). It will be optimized for enabling unprecedented characterization of spin liquids, quantum magnets, thermoelectric materials, battery materials, liquids, and soft matter.

ORNL Contact: Saurabh Kabra (



CUPI2Da time-of-flight imaging instrument, will be designed for imaging dynamic processes in natural and engineered materials. It will have a transformational impact on scientific studies such as energy storage and conversion (e.g., batteries, fuel cells), materials engineering (e.g., additive manufacturing, advanced superalloys), nuclear materials (e.g., novel fuel cladding and moderators), cementitious materials, biology and ecosystems, and medical/dental applications.

ORNL Contact: Saurabh Kabra (



EXPANSE, a wide-angle spin echo instrument, will be used for experiments involving high-resolution (neV-μeV) dynamic processes across a wide range of materials, including soft matter, polymers, biological materials, liquids and glasses, energy materials, unconventional magnets, and quantum materials. It will incorporate wide-angle detector banks, providing approximately two orders of magnitude Q-range and a wide wavelength band providing approximately four orders of magnitude in Fourier times.

ORNL Contact: Saurabh Kabra (



PIONEERa high Q-resolution (maximum unit cell: 107 Å3), single-crystal, polarized neutron diffractometer, will be capable of measuring very small crystals (i.e., x-ray diffraction size or ~0.001 mm3), ultra-thin films (~10 nm thicknesses), and weak structural and magnetic transitions. It will significantly lower the sample size barrier for single-crystal neutron diffraction.

ORNL Contact: Yaohua Liu (



QIKR, a general-purpose, horizontal-sample-surface reflectometer, will be designed to exploit the increased brightness of the STS to collect specular and off-specular reflectivity data significantly faster than existing instruments. Delivering this brightness within a broad wavelength band will permit collecting complete specular reflectivity curves using a single instrument setting, enabling “cinematic” operation by which the user turns on the instrument and “films” the sample as it changes in the neutron beam.

ORNL Contact: John Ankner (



VERDI, a versatile diffractometer, will have full polarization analysis capabilities for complex magnetic structure studies in powders and single crystals. The instrument will allow routine measurements of milligram-size samples, small-moment compounds, and diffuse signals. It will probe magnetic local and long-range ordering in quantum and functional materials that exhibit emergent properties arising from collective behavior.

ORNL Contact: Saurabh Kabra (




Next Steps
In addition to the eight selected neutron scattering instruments, the STS will have the capacity for another 12 beamlines and the project must plan for a future full build-out of the beamlines. All 12 of the instrument concepts developed in the submitted proposals will be used to help refine facility interfaces and requirements, including space needs, moderator optimization, floor loading and arrangement of instruments in the buildings. A process is being developed to propose additional instruments at all of the ORNL neutron sources, including STS.

Additionally, the Instrument Systems group is designing highly shielded spaces surrounding the STS target monolith where all 20 instruments will converge. Many of the instrument choppers will reside in these spaces, along with neutron guides and maintenance shutters. These spaces will be covered with removable shield panels, only removed during facility maintenance periods to allow personnel access.



Instrument bunkers on both sides of the STS target monolith.