A Helping Hand
Users find a collaborative environment in which to probe materials.
For more than three decades,
ORNL's Shared Research Equipment
(SHaRE) User Facility has
provided researchers from universities,
industry and other national laboratories
with two unique commodities: access to an
unmatched array of state-of-the-art electron
microscopes and collaboration with
a highly skilled staff of scientists. These
combined resources enable SHaRE's users
to investigate and solve previously intractable
problems in the fields of materials
science, microscopy, physics and chemistry.
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![Users at SHaRE investigate the structure, composition and chemistry of a wide range of materials.](images/a13_p22sm.jpg)
Users at SHaRE investigate the structure, composition and chemistry of a wide range of materials.
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As a result of the facility's singular
research capabilities, competition for the
opportunity to conduct work at SHaRE
is intense. Potential users must submit
project proposals for review by the facility's
proposal review committee, which consists
of the nation's top materials scientists and
microscopists. SHaRE's director, Karren More, explains that the facility is not
only selective in terms of the research
proposals accepted, but also looks for
research that will maximize the facility's
capabilities. "We ask users to justify why
they need these specific instruments to do
their research," More says. "They're very
specialized instruments, so want to ensure
they are reserved for only the best science."
In the case of SHaRE, "the best science"
runs the gamut of basic materials science
issues, as users investigate the structure,
composition and chemistry of a wide
range of materials. "We have proposals to
do just about everything," More says, "but
our focus is on solving materials problems
that require high-resolution analytical
electron microscopy."
Because SHaRE has a variety of
specialized electron microscopes, users
can examine features of materials that
are measured in millimeters down to
millionths of a millimeter. Researchers
can also examine the same material
with different techniques. More says that
scientists can probe a material's topography,
morphology, grain boundary
structure, atomic structure and composition,
depending on the type of study the
user is conducting. "All of their activities
are ultimately related to the physical and
chemical structure of the materials with
which they are working," she says. "By
studying the properties of the materials,
they are conducting very fundamental
research to understand the mechanisms of
how materials behave."
An interactive research environment
Like most of ORNL's user facilities,
SHaRE maintains an in-house research
mission, as well a user program. When
not supporting users, staff members
conduct independent research focused on
achieving an advanced understanding of
how materials are structured and atomicscale
microanalysis techniques. As a result
of this arrangement, SHaRE users have the benefit of collaborating with scientists
who continuously work at the leading
edge of materials science and electron
microscopy research.
More notes that while most users have
a clear sense of what they wish to accomplish
with their research projects, they
often require staff support from SHaRE
to help them achieve their goals. "This
is a complicated field," she adds. "We do
not expect users to conduct their research
in isolation during their visits to the lab.
Rather, we attempt to provide a very interactive
research environment by assigning
experienced staff members who work
directly with users and help them conduct
their experiments. When users collaborate
and interact with our staff, the result is a
higher quality of research."
Collaboration and interaction
Kevin Field, a SHaRE user and a graduate
student at the University of Wisconsin,
echoes More's assessment of the importance
of the facility's uniquely skilled staff.
"When we come to SHaRE, we conduct
all of our work with a staff scientist, so we
have access to expertise that might not be
available otherwise. I have been collaborating
with Jim Bentley, a SHaRE scientist
who has been doing this kind of work for
decades. I have gained tremendous knowledge
simply by working with someone who
has been in the field for so many years."
Field's research at SHaRE involves
analyzing irradiated steel alloys to understand
how these materials would respond
to radiation if they are eventually used
in next-generation nuclear reactors. Part
of his research involves using several
different SHaRE instruments to examine
irradiated steel samples, characterizing
the extent of the phenomenon known
as "radiation-induced segregation." The
condition occurs when atoms have been
knocked out of place by energetic particles
in such a way that the uniform crystal
structure of the steel is replaced by an
uneven distribution of certain elements.
This reaction can cause the steel to weaken
and eventually crack. Stressing that reliability
is a critical concern for steel used
in reactor vessels, Field explains that he
and his colleagues are trying to determine
whether this phenomenon also occurs in a
variety of steel alloys. "If it does," he says,
"we want to understand the factors that
cause such conditions to occur."
Kelly Perry is a SHaRE staff scientist,
but until a few months ago she was
a SHaRE user and a graduate student
at Rensselaer Polytechnic Institute in
Troy, New York, studying the structure of
polybenzimidazole (PBI), a polymer with
critical applications in the development of
membranes for hydrogen fuel cells. These
fuel cells could be used for combined heat
and power units in homes, as well as in
methanol-fueled backpack power sources
for soldiers in the field. Understanding
more about the structure of PBI is a goal
along the way to developing more efficient,
longer-lasting fuel cells.
As a graduate student, Perry's research
involved working with SHaRE staff to
determine if relationships existed between
the structure and physical properties of
PBI membranes that had not previously
been investigated. During the course of
the study, Perry and her SHaRE colleagues
found that, because PBI is 90 percent
liquid, the membranes are difficult to
study with electron microscopy. They
also discovered that the material is easily
dehydrated and damaged by the electron
beams of the facility's microscopes. Perry
and her SHaRE colleagues addressed the
problem using a cryogenic transfer system
that enables researchers to freeze PBI
samples using liquid nitrogen and keep
them frozen throughout their analysis.
The process protects the samples from
becoming dehydrated or degraded by the
microscope's electron beam. However,
Perry points out that analyzing a frozen
sample presents its own set of challenges,
both in terms of sample preparation and
in distinguishing between characteristics
of the sample and anomalies that might
have been induced by the freezing process.
"It takes time, patience and practice to
understand many of these specialized
techniques," Perry says. "SHaRE has some
of the country's best microscopes and most
advanced equipment for sample preparation,
both of which are required to perform
high-quality microscopy."
Something new every day
More stresses that the true value of
the SHaRE user facility is its ability to add
depth and breadth to the research experiences
of users like Field and Perry. "Our
specialty is the analysis of the composition
of materials. There isn't a similar
collection of instruments anywhere in the
country for doing this kind of research."
More adds, "It's not that other facilities
don't have any comparable instruments,
but our success comes from combining the
array of instruments we have for doing the
full range of materials characterization
with the expertise of our staff members,
who are leaders in the field."
One benefit of these resources is the
fact what while many researchers come
to SHaRE to examine a material with a
specific technique in mind, the advice of
SHaRE staff members often leads them to
use several other techniques that provide
additional insight into their project. Perry
says the SHaRE program is about developing
new techniques and new ways to
look at materials and understand them.
Field adds, "My time at SHaRE has probably
been the best research experience I
could have ever had. I learn something
new every day."
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