Peering intently at a monitor, two young researchers from the Department of Physics are getting their first look at microscale wires being developed for use in a particle detector experiment at the Large Hadron Collider in Switzerland.
Ihnjea Choi, a postdoctoral researcher, and graduate student Pedro Montuenga from the Nuclear Physics group are involved in a research and development project for the famous CERN collider that probably makes them the envy of many young physics researchers. But during this week in late November in the Beckman Institute’s Microscopy Suite basement location, they are novices, learning how to operate the facility’s scanning electron microscope (SEM) for the first time.
And, along with their trainer, microscopist Cate Wallace, they are anxiously awaiting their first views of what these four small tungsten wires look like when brought into focus on the facility’s SEM. With its magnification power of up to 800,000 times for data collection and 200,000 times for rendering meaningful, publishable images, that first glimpse of one’s sample at those scales and with high resolution is often an exciting moment for researchers using the SEM.
Choi and Montuenga are seated, faces a foot away from the screen of one of the two monitors providing images and information from the SEM, which itself is a couple of feet away to the right, with a heavy metal skin protecting the people using it from the x-rays emanating from inside. Wallace stands between the SEM and the pair, providing guidance by both word and expert movements of the keyboard mouse. A green circle and crosshairs move over the screen as they search the sample. For now, she is like a driver’s ed teacher, sometimes letting her students do the driving and sometimes taking the wheel herself.
“Just take the contrast and drag it down,” she advises before taking over the mouse and showing them how to adjust the image. Slowly, with each screen refreshment, a rough cylindrical object starts to appear. “Drag it up a little bit. Now you can see something.”
“Yeah that’s the wire,” Montuenga said.
“But we don’t know which wire,” Wallace responds.
“This should be the first one,” Montuenga says, and with another refresh, “Oh, wow.”
Their attention is split between the instructions for operating the SEM and the screen before them, as they try to replicate Wallace’s mastery of the machine. “We had a crash course yesterday,” Montuenga said.
While the two physicists are using the SEM as part of a project looking for the smallest known particles, another pair of students from the Department of Crop Sciences used it a little later to look at something much bigger: pollen grains. They were trying to find a perfect representative of their sample for a paper being submitted to a peer-reviewed journal.
Sumin Kim and Stella Kim also got a crash course in use of the SEM, with Wallace guiding them through their initial efforts at getting a high-resolution magnified image of a pollen grain — one that would look as close as possible to how it does in nature.
Wallace has tried “pumping” the SEM to add humidity to it, so the samples will be full and lifelike when they image them, and now they are waiting with each screen refreshment and increase in magnification for the grains to appear.
Sumin Kim sees it first. “That’s it, that’s a pollen grain. I’m excited it’s working.”
Microscopy Suite manager Scott Robinson enters the SEM room to check on the progress. “That looks like what we saw yesterday, the same little dudes.”
Sumin Kim agrees, then asks, “Can we make them fat again?” — a request that draws chuckles.
Unfortunately, giving them a fat, natural look proved difficult, so Wallace and Robinson later conferred on ways to make that happen and invited the Kims back for another try.
Equipment, Staff Make for a Unique Resource
Those processes go on every day in the Microscopy Suite, which serves faculty and student users from materials science, engineering, and the biological sciences, to name a few. The instruments in the Suite include four main modes of imaging: light microscopy, scanned probe microscopy, electron microscopy, and x-ray computed tomography (CT). A confocal Raman imaging system was added in the past year for three-dimensional information on the location of molecules in tissue samples and in materials such as polymers.
Between the state-of-the-art equipment and staff, the Microscopy Suite is able, Robinson said, to meet a variety of needs and serve users like no place else on campus.
“We are really lucky to have all these different pieces of equipment and we’re lucky to have multiple ways of imaging something for someone,” he said. “Sometimes it’s simple and sometimes it’s not, but our mission to translate what they want done, give them results on a system, and then evaluate how those results came out.”
In addition to Robinson and Wallace, Microscopy Suite staff helping its users includes Leilei Yin, Dianwen Zhang, and Mark Bee. Zhang also does training, as well as making adjustments to the equipment, as he explained while helping a postdoc from the Rogers Research Group on the confocal system.
“Most of the time I do the training and then they can directly handle it after training,” Zhang said. “For some special cases like this one, where we have to modify things, then I have to improvise a technique.”
“We have a great team,” Robinson said. “We are aware that in some cases we are more expensive than other places, but we have a great team and we have great equipment.”
That allows the Suite to adapt to users’ needs, such as trying the transmission electron microscope (TEM) when the SEM isn’t getting the job done.
“We can just take them down the hall and let them look at it in the TEM,” Robinson said. “Something that has a particle size that is small, sometimes you can do it on the atomic force microscope. We have all these options, including micro-CT, so it’s just awesome.
“We have such a good crew and such good equipment, so we have to take that extra step. Sometimes we have to follow through and make sure that what we did worked. It’s our job to say ‘Yes.’ And that’s the way I look at it.”
The atmosphere in the Suite is informal and collegial. The staff works with users in training and problem-solving. And Robinson’s office there is busy with those stopping by for help and advice on using the equipment.
One who stopped by during the week was Jason Patrick of the Autonomous Materials Systems (AMS) group. Patrick was in the process of submitting a paper to Nature Materials, and had used the micro-computed tomography (Micro-CT) instrument in the Suite to look at vascular networks used in self-healing materials.
“Ever since I came to Beckman, the Microscopy Suite been really, really helpful,” Patrick said. “Micro-CT for instance, there’s no way to see inside the vascular networks and these samples because they are not translucent. So that was really the only way that we could visualize them.”
A fellow AMS group member is Amanda Jones, who uses the Suite for visualizing such materials as complex polymer matrices in research aimed at developing self-healing batteries. She often pops into Robinson’s office seeking advice, such as when she asked about using the Suite’s diamond knife for extremely small scale cutting of samples
“I’ve done that a lot of times before,” Jones said of her pop-in visits. “Normally he will come in and help me whenever I need it, but I’m trying to be a big kid and do it myself.”
Jones has been a user of the facility for four years. She describes Robinson and the Suite as “awesome.
“Scott’s always around. He trains you and then you are free to use it. Usually if I’m doing something, especially something really important, he always comes in and helps me get things just right.”