Executive Summary One of the pillars of America's economic success is…

Executive Summary
One of the pillars of America's economic success is the strength of its research and
development enterprise. The American Competitiveness Initiative (ACI) will build on
this success and enhance innovation. Neutron measurement methods are indispensable
for developing many of the key technologies and materials that will lay the foundation of
future economic growth. Indeed, the unprecedented growth in the application of nano-
scale functionality requires measurement methods, such as neutron scattering, that access
the nano-scale. The NIST Center for Neutron Research (NCNR), which has a proven
track record of providing world-class neutron capabilities to the R&D community, is
especially well positioned to implement a range of instrumentation innovations.
However, unfulfilled demand for instrumentation and limited resolution and neutron
intensities present serious barriers to achieving the full potential of emerging scientific
and technical opportunities.

The novel capabilities enabled by the proposed NCNR expansion and the addition of new
instruments housed in a new facility illuminated by a bright new source of cold neutrons
would help to overcome these barriers. The expansion would modernize a beam line that
currently serves a single instrument into a multiplex system, optimized to serve five or
more instruments simultaneously. State-of-the-art optical devices and neutron polarizing
systems would significantly enhance instrument performance, and improved detectors
would extend instrument sensitivity to weak signals. Such new capabilities are ideally
suited to answer pressing questions that emerge as researchers try to understand and
harness the fascinating properties of matter at the nano-scale and will provide
opportunities for the U.S. to stay at the leading edge of science and technology
development.

Cold Neutron Imaging
Cold neutron imaging offers unique measurement capabilities in support of American
industry. Water and its spatial distribution play central roles in biological systems such
as membranes, microfluidic devices, and many other physical systems of great practical
importance such as hydrogen fuel cells. Cold neutron imaging coupled with new
detectors will increase the current sensitivity to water and its spatial distribution by orders
of magnitude. This will open new opportunities to study water transport mechanisms in
geological samples, biological systems, and hydrogen fuel cells. The deep penetration
and enhanced phase sensitivity of cold neutron imaging would enable high throughput,
non-destructive evaluation (crack and defect detection, residual stress) of mechanical
components to improve manufacturing techniques.

Soft Materials
Practical applications of soft materials like surfactants, colloids, polymers, and biological
macromolecules are widespread in our modern economy. Neutron scattering is an
essential tool for characterizing the structure and dynamics of these systems because
neutrons are extremely sensitive to hydrogen, which permits detailed investigations of
hydrogenous materials. Neutrons also see hydrogen and deuterium quite differently
which allows scientists to enhance structural features by chemically substituting
deuterium for hydrogen. Because neutrons are neutral particles, they can penetrate
deeply into materials. This property can be exploited to study complex systems under
confinement or extreme environments, or even to observe materials during manufacturing.
And neutrons can probe key molecular motions over a wide range of time and length-
scales that are not accessible by any other technique.

While soft materials are already ubiquitous in our lives, improvements in our ability to
understand and control their function will lead to even broader applications in the future.
These new applications could include: smart biomedical materials; polymer electrolytes
and membranes for advanced batteries and hydrogen fuel cells; polymer thin films for
advanced coatings and microelectronics; and materials for drug encapsulation and
delivery; and advanced nanocomposite materials. Advanced neutron scattering methods
are essential to realizing this promise.

Hard Materials and Chemical Physics
Controlling the behavior of materials and small molecular systems at the nanometer scale
is central to a wide range of technologies with immense societal impact. The ever-
growing demands for greater data storage and faster data retrieval and processing require
improved characterization of complex magnetic structures. Because neutrons couple
strongly to magnetism, they are ideal for this task. Neutrons are also sensitive to
absorbed hydrogen and can characterize its diffusive motion, which makes them essential
to the goal to develop new materials to store and transport hydrogen efficiently.
Neutrons are also crucial to better understand and control chemical processes and
catalysis. Finally, the development of new materials that will fuel the growth of future
technologies such as quantum computing, solid state refrigeration, and next generation
sensor technologies require improved understanding that can only be obtained using
neutron methods.

To advance the performance of these important functional materials, methods that
employ and measure the magnetic polarization of the neutron are required. With
polarized beams also come new options to enhance resolution without intensity loss
through spin resonance techniques. The proposed expansion of the NCNR provides the
opportunity to develop instrumentation that takes full advantage of modern polarization
techniques to create measurement capabilities that don't currently exist.

Measurements of Neutron Properties
Precision measurements of fundamental neutron properties expand our knowledge of the
basic forces of nature and reveal new physics to help explain the birth and development
of the universe. These include studies of neutron beta decay, weak nuclear interactions,
and the neutron electric dipole moment. Some experiments benefit from large, divergent
beams with the highest possible flux. Others require smaller beams with high brightness.
The NCNR expansion offers beamlines with substantially higher neutron flux and
brightness tailored to optimize the performance of these experiments, with state of the art
neutron optics and new opportunities for high beam polarization and precision
polarimetry. It enables an exciting new generation of experimentation that will address
the most pressing problems in this field and advance the frontier of fundamental physics.