Beckman Institute's New Nano-CT Will Be First for Use by Illinois Researchers

Within a few months researchers from the University of Illinois will get an opportunity unavailable to faculty members on any other campus - the chance to use x-ray microscopy instruments at the Beckman Institute that are unmatched in their imaging power.

It often happens with a new technology that anticipation starts to build as the time gets closer for its public debut. Staff members from the Beckman Institute's Imaging Technology Group (ITG) are finding that's the case for the one-of-a-kind array of computed tomography (CT) instruments that are in the process of being installed in ITG's Microscopy Suite.

By the end of this year, the Microscopy Suite will be home to a quartet of high-performance x-ray CT instruments for imaging an unprecedented range of scales and samples, including a unique nanotomography (nano-CT) microscope that will provide unparalleled, three-dimensional images of structures at the nanoscale.

"We're really excited because we are going to have four different components. We're going to be able to cover a lot of sizes and samples, and a lot of resolutions.
- Scott Robinson

ITG's Microscopy Suite has had a Skyscan Micro-CT unit for two years and in March added a higher resolution micro-CT unit that was the first of three x-ray CTs to be acquired from manufacturer Xradia with an historic National Science Foundation (NSF) grant. When the nano-CT is installed sometime later this year it will, for the first time on a university campus, give researchers high resolution, nondestructive, internal imaging of materials at sub-cellular scales.

The nearly $2M NSF Major Research Instrumentation (MRI) grant for acquiring three new CT units was one of the largest of its kind ever awarded and the largest MRI grant ever to the University. Microscopy Suite Manager Scott Robinson said the original grant proposal to the NSF had 47 faculty members as co-authors. Several of the co-authors, including principal investigator Paul Braun, are faculty members in the Department of Materials Science and Engineering, but co-authors of the grant came from many departments on campus - as does interest in using the nano-CT when it becomes available.

"We have people asking us about it and we have some people who are scheduling already," Robinson said.

When the nano-CT is installed it will greatly expand the ability of the Microscopy Suite to serve researchers. Microscopist Leilei Yin will be in charge of the suite of CT units; he said ITG staff members and Xradia are working together to create something unique.

"It's special for us and it's special even for them (Xradia)," Yin said. "This is the first place in the U.S. to have a whole system installed at a university, both micro-CT and nano-CT. I believe it is the only one that is accessible to outside users. Some other government agencies might have comparable systems but they are not open to the public."

Robinson said the units will provide a new world of imaging possibilities for Illinois researchers.

"We're really excited because we are going to have four different components," he said. "We're going to be able to cover a lot of sizes and samples, and a lot of resolutions."

The new Xradia MicroXCT™ has been in operation since March and has about five times better resolution than the Skyscan micro-CT, with resolutions that can at times approach nanoscale. A second component is scheduled to be installed this spring that will give better than one micron resolution. The Xradia nanoXCT™ will complete the acquisition and offer high-resolution x-ray tomography capabilities that can provide nondestructive, internal 3-D imaging of samples as thick as 20 micrometers while resolving features as small as 30 nanometers in width.

"Right now we're pushing one micron resolution and we might even be better on some samples," Robinson said. "Once we get below one micron then we're really in the nano range, in nanometers. Eventually we hope to have 30 nm resolution on particular samples."

The new units will get their very own space in the Microscopy Suite, with remodeling set for an area west of the Suite's rooms in the Beckman basement that will eventually house the three new acquisitions, the Skyscan micro-CT, and offices.

"It's a great opportunity for us to do this, to be able to design the facility from the ground up, from the basement up, and do it right," Robinson said.

The technology can be used for imaging a wide range of samples, such as biological materials at their cellular level, or for imaging at the nanoscale, including industrial materials like semiconductors or natural ones like geological samples.

Robinson and Yin expect users from varied departments on campus to utilize the CT units, especially the nano-CT. Co-authors of the grant proposal included researchers from more than 20 departments on campus representing fields as diverse as animal sciences and mechanical engineering.

Once the entire array of CT units are installed and operating, researchers from many different fields can gain high resolution imaging results not possible with other techniques on samples such as bone tissue, nano-electromechanical systems (NEMS), pharmaceuticals, and many other materials.

Yin is already working with graduate student Wei Zhu of researcher Richard Masel's laboratory using the Xradia MicroXCT for a project involving fuel cells. The new microscope hasn't disappointed.

"It has performed better than we expected," Yin said. "Her project is developing fuel cells which are made of graphite. Graphite is conductive and opaque, which means we cannot characterize it with either an optical microscope or an electron microscope. Only an X-ray machine can look through that. They have water in graphite channels and the only way they can monitor the progress of water droplets is through X-ray. We have gotten some very satisfying results. The other micro-CT doesn't have the same signal quality."

The CT microscopes will be available 24 hours a day to University of Illinois faculty, staff and students, and their campus and industry collaborators. Microscopy Suite staff trains users to independently operate the units and assists them with sample preparation, acquisition, processing, analysis, and storage of the CT data. With each new project, the Microscopy Suite staff members also learn more about how to get the best results from the microscopes.

"The trick is going to be getting the contrasts that we need and learning how to deal with every particular sample because some samples are going to be really easy and some are going to be really difficult," Robinson said. "It's just like what we do with everything else: we are going to develop the techniques to be able to do this, learn what agents we can use to get contrast, what accelerating voltage we're going to use. It's really, really exciting."

Robinson added that a big component of having the increased imaging capacity offered by the new CT microscopes lies with the reconstruction software that is developed from the imaging results.

"What people are going to do is get these datasets, and then they want to take these datasets and get something that they can manipulate," he said. "And this is part of the deal, part of the idea of imaging, giving people 3-D images. We just add the icing to the cake."

It's a new level of service to researchers that Robinson said staff members are excited about.

"People are going to start bringing things in," he said. "We're finally going to have what people have been asking for upstairs."

With the leap forward in technology, however, comes a responsibility.

"This is a grant proposal that had the support of 47 faculty members," Robinson said. "We got everybody on board on this. It will be our job to make sure that everything works perfectly.