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October 22, 2014

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SCIENCE:

In UNLV’s research arsenal, ‘The Machine’ is the star attraction

Here’s where Caltech and MIT go to tap UNLV resources

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Ian Whitaker

Ph.D. candidate Michelle Mezher works on the Surface and Interface Analysis and Modification System. The machine is used by UNLV’s Energy Conversion Research Group led by Dr. Clemens Heske to study surfaces and interfaces of devices devoted to the conversion of energy.

'The Machine'

Dr. Heske's Energy Conversion Research group works on the Surface and Interface Analysis and Modification System. The machine is used to study surfaces and interfaces of devices devoted to the conversion of energy. Launch slideshow »

The gleaming behemoth in the bowels of UNLV’s Science and Engineering Building doesn’t really have a name. The scientists that work with it refer to it simply as “The Machine.”

It’s the star of the building’s science tours and resembles something a mad scientist might keep hidden away in a musty basement. Filling a room built specifically for it, there’s just enough space for its human researchers to scurry about. Shiny metal hemispheres bloom out like mushroom caps above a labyrinth of specially made stainless steel chambers and pumps.

The machine creates a super vacuum and shoots X-rays to allow analysis, at the atomic level, of surfaces of various kinds of materials. Few machines in the world can pull off what this machine does. The understanding of some of the most complex aspects of solar and hydrogen technology will likely start here.

When operating, the machine — which was custom engineered and pieced together starting in 2004 — creates a constant buzz, like a tree full of cicadas.

Like all epic beasts, this one comes with its own history. It was brought to UNLV in 2004 by chemistry professor Clemens Heske, crammed into such a small space in UNLV’s chemistry building that it violated fire codes and left Heske no room to expand.

When the Science and Engineering Building opened in 2009, the machine was part of a mass exodus. Twenty-six research groups left their humble offices around the university for space at the new facility. Over a span of 6 months, the machine was disassembled and moved piece by piece across campus to a 1300 square foot room on the ground floor specially built for it.

The instrument is so sensitive that someone walking in the hallway next to it will interfere with the measurements.

As the assistant research director the UNLV’s new science mecca, Eric Knight is something of the on-site landlord and property manager, seeing to it that researchers have what they need to do their work. For Heske and his group, which focuses primarily on energy research, that meant designing a floor that could withstand the machine’s strict standards. Because it images materials down to the atom, the machine cannot move more than 50 millionths of an inch each second. It sits on an isolated concrete slab reinforced with an injection of solidifying epoxy just to keep it stable, while the microscope “floats” in the chamber on a sophisticated spring-based system.

Sometimes fixes to the machines are not as sophisticated. When it was discovered that vibration of the vacuum hoses “shook” the machine enough to throw off measurements, the hoses were put in a few $5 buckets from Home Depot, covered and filled with cement. Ta-da.

Knight said many of the tours he does regularly at the building involve people marvelling at the machine at some point.

“It’s definitely our most sophisticated instrument in the building,” Knight said. “I deal with it on a daily basis and sometimes I forget how cool it actually is.”

Other research groups can take what has been learned and published by the UNLV team and apply it further until it becomes a daisy-chain of scientific progress. The UNLV team works closely with partners at MIT, Caltech, University of Arizona and Colorado State University. They also collaborate with groups at the National Renewable Energy Lab and Lawrence Livermore, Lawrence Berkeley and Argonne national laboratories as well as, in Germany, the University of Würzburg, the Helmholtz-Center Berlin and Karlsruhe Institute of Technology.

Despite its imposing presence, caring for the machine is more like constantly swaddling a fussy baby. Everyone in the 11-member research group dedicated to it has an essential duty, from making sure it’s computers are up to date to ensuring that the many components are functioning like clockwork.

When 23-year-old Ph.D. hopeful Michelle Mezher isn’t gathering the data the machine spits out after hours and sometimes days of nonstop analysis, her job is babysitting the ultra-high-vacuum turbo pumps that keep the interior of the machine at around the same atmospheric pressure as outer space. The insides of the chambers have a messy tendency to attract moisture as well as exude trapped gasses, all of which will throw off a measurement during experimentation. A pristine vacuum is key.

In the early months she struggled to keep up with the maintenance while also working on her own research. She spent half of her time in the lab just troubleshooting pumps. Now she’s mastered it and has streamlined the process to save time.

It’s not the most glamorous job, but it reminds the pint-sized Californian of her days building competition robots with an all-girl robotics team at her Catholic high school in Calabasas.

Mezher attended the University of San Diego for her undergraduate studies. A handful of awards and prestigious grants later and she found herself visiting graduate schools competing to finance her passion in physical chemistry. When scientists at the University of South Carolina heard that she had also stopped by Dr. Heske’s Surface and Interface research group at UNLV, they raved. That’s when she knew.

“If Clemens and his machinery weren’t here I would have found a different university,” she said. “My interest is in surface science, and there are so few scientists in the United States that specialize in that.”

Through her work with Heske’s group, Mezher has earned a prestigious German scholarship and half a year’s worth of research with her European peers.

But home grown prodigies like Mezher aren’t the only ones who get a crack at the machine. Students and post-doctoral researchers from India, Italy, Mexico, China, Sri Lanka, Lebanon, Germany, Vietnam, Trinidad and the United States have all left their mark.

Exciting research is somewhat commonplace at UNLV these days but the work done by Heske and his crew is particularly groundbreaking. By analyzing surfaces with laser-like precision, the group can find out why specific materials behave the way they do. For liquids it would be the difference between knowing why oil and water don’t mix but alcohol and water do. For solids, Heske says the process is a little more complex.

“In the solid state world, one can always force two materials together,” he explains. “But the question is what happens when you do that.”

In a process dauntingly titled X-ray photoelectron spectroscopy, the machine works by blasting x-rays at the surface of a material and trapping the electrons that escape from it. By measuring the energy of the escaped electrons and cross-referencing past experiments and existing research, Heske and his group can pinpoint the elements present in a sample and the chemical environment they exist in. The data is then analyzed and shared with clients and fellow researchers.

The rarity of the machine means a list of partners from the Energy Department to companies seeking a deeper understanding of products as simple as laser pointers, but the group takes a special interest in experimenting with solar cells.

Heske’s group analyzes prototype cells made in labs as well as cells that are mass produced for consumers. At present, the most advanced CIGS thin film solar cell — an alternative to the more common silicon cell — can achieve around 20 percent efficiency, while industrial versions clock between 10 and 14 percent.

Even a one percent increase in the efficiency of mass-produced solar cells would be considered a breakthrough, Heske said.

Cells made in the lab are at the apex of solar technology but tend to stymie manufacturers who can’t produce them cheaply enough for a mass market. The challenge for cell companies is finding ways to replicate the efficiency of the prototype at a price point friendly for mass-production. That’s where the science comes in.

Mezher said that in the past, manufacturers of CIGS cells would place them on a layer of highly expensive glass. When a curious scientist swapped the costly glass for everyday window glass, the efficiency of the cell skyrocketed due to the sodium in common glass, causing grains in the solar film to expand. With the help of "the machine," scientists like Mezher and Heske can find out exactly why this happens.

By pinpointing weaknesses and strengths in the designs of both the lab and production cells, the group can help companies keep cell technology on the cutting edge while reducing the cost for everyday consumers. Heske said that a cell manufacturer in Europe estimated the savings from improving the efficiency of their product by one percent to be equal to half the cost of their entire production facility.

Though renewable energy is a common theme of their research, it’s not limited to just solar technology. The group also experiments with nuclear fuel, hydrogen and fuel cells among others.

While they haven’t made a breakthrough on the level of the curious scientist with the common window glass, they realize that those things happen rarely in science. They take pride in the fact that they contribute to the scientific advancement of renewable energy one precise measurement after another.

“Sometimes you don’t get that magical breakthrough that gives you that 5 percent [increase in solar cell efficiency],” said Kim Horsley, another graduate in Heske’s group. “It’s a work in progress and it will be a work in progress for a long time.”

After his grandmother once caught him off guard about the practical value of his early research by bluntly asking him, “So what is it good for?” Heske has used the “Grandma Question” to help him and his group stay focused. He knows that any one of his undergraduates, graduates or post-doctoral group members could answer that question with ease.

“They want to make a difference in the world,” he said. “They feel that if they look at solar cells or batteries or nuclear fuels, they can really make a difference.”

Ian Whitaker is news editor for the UNLV newspaper, Rebel Yell.

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