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Apr 28, 2023

Inside the UNLV Nuclear Engineering Lab

Lab develops new radiation detection technology while building a pipeline for

Lab develops new radiation detection technology while building a pipeline for the next generation of nuclear engineers.

Doctoral student Charles Han works inside the UNLV Nuclear Engineering Lab, which is working to develop new technologies for radiation detection. (Josh Hawkins/UNLV)

The cautionary, bright yellow signs posted throughout the room, paired with the words "radioactive material," would make any visitor of the Nuclear Engineering Lab at UNLV take heed. And while the lab does keep small radiation sources under several layers of lock and key for research purposes, there's another area — smaller, and without much fanfare, but with a bit of pun — that reveals the lab's ultimate purpose.

Posted up and down the length of a file cabinet — a makeshift, bulletin board of sorts — near the corner of the room are a series of certificates noting recent student achievements under the title, "Enriching Nuclear's Human Element."

No, the Nuclear Engineering Lab at UNLV doesn't enrich uranium-235. It does, however, cultivate the next generation of nuclear engineers.

Let's take a peek inside.

The Nuclear Engineering Laboratory has a name that's "simple and to the point," says its director Alex Barzilov.

"It's a normal working environment, like your garage or a machine shop," said Barzilov, a professor of mechanical engineering at UNLV. "It's what we do. We put pieces together and try things."

But the work is much grander — and more important — than Barzilov's description might suggest.

Another way to put it: the lab is at the forefront of novel radiation detection technologies in an effort to support national security and environmental management of radioactive facilities.

The lab does have a backyard garage feel, partly evidenced by the bright red, roll-up overhead door that can be seen from the sidewalk between the White Hall Annex (WHA) and TBE-B. Also contributing to the machine-shop ambience is the chain link fence separating the two main areas of the lab, with a third area — at the very back of the space — dedicated to securing radiation sources.

The first area is dedicated to computational, high-fidelity modeling on nuclear reactor physics projects. One type of reactor they study — molten-salt reactors — are under development, and simulations allow students to study and search for new designs for the nuclear generation of electrical power.

The tinkering begins on the other side of the fence, where students work with devices, like a high-purity germanium (HPGe) detector or a cesium zinc telluride (CZT) detector, to use radiation detection methods for various applications such as assay of radioactive samples and remote radiation sensing using drones.

On the wall above hang two, first-generation drones, one painted camouflage and one adorned with UNLV colors, and evidence of a longstanding partnership with Woosoon Yim's drone lab just down the hall.

The fixed-wing drones that look like mini-airplanes give a nod to the lab's history, and also, to where it's going. Retired mechanical engineering professor William Culbreth started the lab, and Barzilov took the helm when he arrived at the university more than 10 years ago.

The lab has cultivated a longstanding partnership with the Nevada National Security Site (NNSS) and other national laboratories.

These partnerships are also a nod to the Nuclear Engineering Lab's overarching goal: to support national security endeavors through the development of novel radiation detectors.

The detectors are based on semiconductor crystals, which are grown in the lab through a very complex process, and in their final incarnation are able to capture gamma rays. They can be attached to drones — more advanced versions of the ones that currently adorn the walls — to support remote radiation sensing.

"Detectors are attached to the robotic platform which can fly, or drive, and this robot can move around transmitting signals," Barzilov said. "They can go to dangerous areas where people cannot. We’re putting the robots to work for us."

When asked about his background, Barzilov — who has won distinguished teaching and research awards from the College of Engineering in recent years — almost immediately turned the spotlight back on his students, and the work.

"My job is to do some cool new stuff which nobody has done before," he said. "That's what any scientist can say."

Ten graduate students — seven Ph.D. and three master's students — are currently working on a variety of projects at different stages. Barzilov also works with undergraduates, supporting student projects in the college's culminating experience for graduating stuents: Senior Design Competition.

Ph.D. student Kaleab Ayelew has been working with Barzilov to replace HPGe detectors with something better. These detectors — shaped like a large cylinder — are technically the most "state-of-the-art" devices available for first responders to take out into the field to measure radiation levels in the event of a radiological release. However, they need to be cryogenically cooled to minus 196 degrees celsius in order to work.

"It's very hard to deploy this in the field," Barzilov said. "We need something that's less expensive, more efficient, and something that can operate at ambient-temperature."

Graduate students and Barzilov have been trying to find a solution. To do so, they’ve been testing new materials by growing their own inorganic semiconductor crystals using the Bridgman method, and hybrid organic-inorganic semiconductor crystals using solution techniques.

In the Bridgman furnace, a tall thermos-like device that opens like a suitcase, they grow inorganic crystals from their own melt. The furnace is separated into three temperature zones, and can grow more than one crystal at once, but usually, the team grows them one at a time.

"We prepare a pure powder, which is heated and becomes liquid, and then we’ll cool it so that the crystal grows," Barzilov says. "We are going from powder, to the material, to the device, and then to the application. We cover the entire continuum."

As a result of his work in the lab, Ayelew already has a job offer from NNSS waiting for him upon graduation. That's common for the students involved in the Barzilov lab.

"Many of my students get a job before they graduate," Barzilov said.

This positive track record is encapsulated in a new project that Barzilov launched in 2021: the Nuclear Security Science and Technology Consortium. With $3 million in funding from the National Nuclear Security Administration through the Minority Serving Institution Partnership Program, the consortium is designing and building a sustainable pipeline of student talent between the Department of Energy's sites and labs, and the minority-serving institutions that are part of the program.

The consortium has fully funded nine Ph.D. students, including two students each at the partner universities, University of New Mexico and the University of Illinois Chicago.

"We’re building a really smooth pipeline of workforce development," Barzilov said. "Our students are able to get internships and employment with the National Laboratories. It's good!"

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