Collaborators from Photon Sciences and Sustainable Energy Technologies stand behind the new transmission x-ray microscope (TXM) at Brookhaven’s National Synchrotron Light Source. From left: Yu-chen Karen Chen-Wiegart, Can Erdonmez, Jun Wang (team leader), and Christopher Eng.
new X-ray microscope probes the inner intricacies of materials smaller
than human cells and creates unparalleled high-resolution 3D images. By
integrating unique automatic calibrations, scientists at the U.S.
Department of Energy’s Brookhaven National Laboratory are able to
capture and combine thousands of images with greater speed and precision
than any other microscope. The direct observation of structures
spanning 25 nm—or 25 billionths of a meter—will offer fundamental
advances in many fields, including energy research, environmental
sciences, biology, and national defense.
innovative full field transmission x-ray microscope (TXM), funded by
the American Reinvestment and Recovery Act, was developed and
commissioned at Brookhaven Lab’s National Synchrotron Light Source
(NSLS), which provides the x-ray source needed to capture images on the
nanoscale. A new paper published in the April 2012 Applied Physics Letters
details the experimental success of a breakthrough system that rapidly
combines 2D images taken from every angle to form digital 3D constructs.
can actually see the internal 3D structure of materials at the
nanoscale,” said Brookhaven physicist Jun Wang, lead author of the paper
and head of the team that first proposed this TXM. “The device works
beautifully, and it overcomes several major obstacles for x-ray
microscopes. We’re excited to see the way this technology will push
Building an extra dimension
team examined, for example, a 20-micrometer electrode from a
lithium-ion battery—as thin around as a human hair. The internal
interaction of pores and particles determines the energy performance of
the battery, and examining that activity requires precise knowledge of
the nanoscale structure.
team took 1,441 2D pictures of the electrode as a machine rotated the
tiny material specimen to capture every possible angle. The challenge
then becomes converting those separate images into a single 3D
structure—one in which every nanometer makes a difference. On this
scale, the usual one-micron wobbles are similar in scale to taking a
portrait and having the subject leap several feet to either side.
this new system, scientists had to manually align every single image or
use software to slowly interpret the shifts. This had two major
limiting effects on the process: first, the sample has to have sharp
internal features or be marked to provide guidelines, which can limit
material types; and second, manual alignment demands so much time that
the total image count peaks in the hundreds. Brookhaven’s TXM changes
the first time, the specimen is mounted on top of a platform with three
sensors that measure nanometer shifts in any direction as the battery
rotates and the microscope takes pictures. The computer recording the
images, after calibration using a gold sphere, then automatically
compensates for any shifts and accurately assembles the images into the
final three-dimensional construct. The entire process takes only four
hours, and that owes more to the x-rays available from NSLS than the
microscope or computer.
The future of 3D
This 3D reconstruction of a lithium-ion battery electrode, composed of 1,441 individual images captured and aligned by the TXM, reveals nano-scale structural details to help guide future energy research.
National Synchrotron Light Source II (NSLS-II), scheduled to come
online in 2015, will exploit the capabilities of this TXM on an even
more radical scale. Imaging that lithium-ion battery took 10,000 seconds
on NSLS, but with the new light source’s higher beam flux, or x-ray
brightness, it will be 1,000 times faster, dropping that time to only 10
addition to direct structural observation, the TXM will also advance
elemental and chemical understanding of materials. Maintaining constant
magnification during spectroscopic imaging, which examines the unique
ways that matter interacts with radiation, scientists will be able to
identify the individual chemical configurations within samples. Research
is currently under way by Wang’s team to demonstrate this capability.
Nanoimaging for industry and national security
TXM was purchased with support from the American Recovery and
Reinvestment Act, designed to spur economic activity and create jobs.
Xradia, a California-based company that specializes in 3D x-ray
microscopy, built the new device. Brookhaven Lab physicists worked in
close collaboration with Xradia engineers, explaining their specific
research goals and performance needs.
has been a very successful collaboration, and Xradia has been our
critical partner in this project,” said Wang. “We are still in frequent
contact to provide them with feedback on the microscope’s performance,
so that future design innovations can be made.”
the focus for the new TXM will likely be on alternative energy fuels
and storage solutions, the fundamental insights have already been
applied to plant root structures, catalysts, and advanced electronics.
The demonstrated success of the 3D imaging system has already attracted
the interest of commercial users, with major corporations such as UOP
and IBM scheduling time at the TXM. The Defense Advanced Research
Projects Agency (DARPA) also plans to use the new microscope to probe
the intricate structures of imported microchips in the interest of
Lab’s National Synchrotron Light Source, NSLS-II, and the TXM research
are funded through the Department of Energy’s Office of Science.
Source: Brookhaven National Laboratory