Accelerator Production of Tritium

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      A Lighter Filling in Earth’s Core

The outer core of the Earth, whose composition until now
has been a mystery, may consist of an alloy of iron and

Researchers in the laboratory created high pressures to make
new alloys of iron and magnesium with the same sound
propagation properties as the earth’s core.

• This is a major step toward predicting earthquakes.
• This research will also be significant for high pressure
alloy manufacturing techniques.

      J.-F. Lin et al., Science 308, 1892 (24 June 2005)
      Funded by DOE BES & National Nuclear
      Security Administration (Carnegie/DOE
      Alliance Center), NSF, the State of Illinois,
      and the W. M. Keck Foundation

      N. Dubrovinskaia et al., Phys. Rev. Lett. 95, 245502
      (9 December 2005)
      Funded by DFG, Swedish Research Council
      (VR), and the Swedish Foundation for
      Strategic Research (SSF)
                                                                          The Density of States of Iron at high temperatures (red curve)
                                                                          is shifted toward lower energies, indicating a softening of the
                                                                          lattice, which decreases the velocity of compression waves.

 Studies in Strain Mapping Help Reduce Fatigue in Materials

Studies conducted at the ORNL’s High-Temperature Materials Laboratory
are helping scientists better understand the overload phenomena during
fatigue. The user study was aimed at revealing the mesoscale explain
mesoscale? changes that retard crack growth rate following an
which can help in developing micro-mechanical modeling.
Computing? Industry/ Manufacturing applications?

Industries such as X (Car producers, NASA, semiconductor
manufacturers?) are interested in exactly what happens at the
molecular scale when materials break.

With this information, we could design better materials and
predict whether certain materials are sufficient in
particular applications.

                                                                               Using neutron diffraction at the HFIR Neutron Residual
                                                                               Stress Mapping Facility, users from the University of
                                                                               Tennessee mapped the elastic/plastic strains in front of
    Who would be interested in this research?                                  the crack tip.
    Is other industry participating?
    Work funded by ???

                                Optimizing Permanent Magnets

 Permanent magnetic materials play central roles
 in the conversion of mechanical energy to
 electricity in alternators, generators and many
 other products and technologies.

 Researchers at APS have developed promising
 ways to enhance magnets, opening new
 performance possibilities in energy
 conservation, miniaturization of magnetic
 devices, and other applications.

D. Haskel et al., Phys. Rev. Lett. 95 (21), 217207 (2005).
                                                                   Unit cell of Nd2Fe14B indicating the location of the two
                                                                   unequal Nd crystal sites that are the focus of this study.
                Funded by DOE
         Capturing Atomic Processes

                                                          Preliminary experiments at the SSRL using electron
                                                          bunches only quadrillionths of a second long have
                                                          illuminated the motions of atoms, including the
                                                          atoms of a microchip.

                                                          These experiments point toward the enormous possibilities
                                                          opened up in 2008, the start target for the Linac Coherent
                                                          Light Source, a machine that will generate light so bright
                                                          and fast that it will:

                                                          -- Discover and probe new states of matter
                                                          -- Understand chemical reactions and biological processes
Single shot image of x-ray diffracted intensity of an
InSb crystal. The ultrafast drop in intensity along the   in real time
central region of the image results from intense laser    -- Image biological materials at the atomic level
induced disordering (i.e. melting).
                                                          -- Image chemicals and material structure on the
Lindenberg et. al., Science 308, 392 (2005).              nanoscale
Gaffney et. al., Phys. Rev. Lett., 95, 127501

        Funded by DOE and in collaboration with several universities and national laboratories

Neutron Reflectivity Reveals Suspected Air Layer under
Water Drops on Lily Pads

•   Dew drops roll off lily pads
    because their surfaces are
    hydrophobic (“water fearing”)
•   An air layer has long-
    suspected under such a drop
•   Removal of dissolved gases
    reduced the layer thickness;
    aeration increased it                                           -6
•   Hydrophobic forces govern                                                                          X-ray Air
                                                                                                       Degassed D2O
    protein folding, lipid                                    10
    aggregation, and hence life
    itself                                         Water            -8
•   [Dhaval A. Doshi, Erik B. Watkins,
    Jaroslaw Majewski, Jacob Israelachvilli,     Air (10 Å)
    PNAS]                                                     10

        Hydrophobic Polymer                                              0   0.05   0.1   0.15   0.2
                                                                                                       0.25   0.3      0.35

                                                                                           Q (Å )

Neutron protein crystallography solves several complex
biological structures.

• Data from xylose isomerase recorded
  181,797 reflections allowing
  researchers to map hydrogen.
• Xylose isomerase helps convert                Bunick and Hanson, ORNL
  sucrose to fructose in the body.

                    Human insulin data
                    using PCS user-
                    friendly display (left)
                    and a schematic of
                    PCS (below)

                                                    Protein Crystallography Station, PCS

     Metal-Organic Frameworks (MOFs): Advanced
     Storage Materials for the US Hydrogen Economy

Future hydrogen and fuel cell technologies
depend critically on the discovery of novel
materials to store large amounts of hydrogen
under ambient conditions. Metal-organic                    MOF5-4D2
framework (MOF) compounds are nano-
porous materials that show promise for
hydrogen storage applications because of their
tunable pore size and functionality.                        x=0.165
Neutron powder diffraction and first-principles
calculations have allowed researchers to
determine the hydrogen adsorption sites and
binding energies in MOF5, the most widely
studied MOF material. These results not only
hold the key to optimizing MOF materials for               Yildirim and Hartman, Phys. Rev.
hydrogen storage applications, but also                         Lett. 95, 215504 (2006).
suggest that MOFs can be used as templates to
create artificial interlinked hydrogen
nanocages with novel properties.            UNCLASSIFIED

        New Methods to Determine Complex Structures of
          Important, Disordered Proteins in, e.g., HIV
 Recently, scientists at the NIST Center for Neutron Research (NCNR) have developed computer
 algorithms that can generate and evaluate ensembles of protein structures in solution. The unique aspect
 of this work is that these calculated structures are subsequently compared to experimental data on real
 proteins using small-angle neutron scattering techniques to determine which structures match the data. In
 collaboration with researchers at the National Cancer Institute, the NCNR scientists have applied these
 new methods to determine the first full-length structures of the human immunodeficiency virus (HIV)
 coat protein, called “Gag.”

            Basic Structure of an                                     HIV Gag Protein Structure Modeling
         Immature Retrovirus Particle                             (A. Rein et al., J. Mol. Biol. - in preparation.)
                                                                   Rg = 31Å                           2

Calculation                             Data       explore                                     0.01
                                                                      MA                              6
                                                                                                                  wm 1 mg/ml (Rg=35±1Å)
                                                                                                                  model 1 (Rg=31Å)

                                                                                                                  model 2 (Rg=38Å)

                                                                                   I(Q) cm

                                                             CA                                       2

                                                                                                          3   4   5   6 7 8 9      2      3        4   5   6 7 8 9     2   3
                                                                                                                           0.01                                  0.1
         ~200 Å                                                                                                                        Q (Å )
                     ~1100 Å

                                               UNCLASSIFIED           Representative Gag Structures
    Yeager et al., Proc. Nat. Acad. Sciences
                                                                             31Å  Rg  38Å
               95, 7299 (1998).

       Neutron Reflectivity Measurements Help to
     Develop Higher Density Magnetic Storage Devices

The discovery of Giant Magnetoresistance
(GMR) has led to the rapid development of
new, high-density magnetic storage devices.
These rely on the phenomenon known as
exchange bias, which is not fully understood.
A microscopic model of exchange bias may
be illuminated by probing the magnetization
changes and the field dependent switching of                   Pinned Layer

                                                            Depth (nm)
the individual magnetic layers that make up
these storage devices. This can be achieved                    Free Layer

using polarized neutron reflectivity (PNR)
                                                    -1100 G – First Cycle   18 G – First Cycle 1050 G – Second Cycle
measurements, which provide sub-nanometer
resolution of the depth-dependent vector
magnetization. By collecting PNR data at
several points along the hysteresis curve, as             S. Moyerman et al., J. App. Phys. (2006)
shown in the figure at right, one can measure
changes in the magnetic properties of the free         In collaboration with San Jose Research Center,
and pinned magnetic layers in a prototypical                   Hitachi Global Storage Technologies
computer hard drive read/write head.          UNCLASSIFIED