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How are elements made?

A conversation with physicist Kelly Chipps

As a young girl Kelly Chipps believed she would become a field biologist. Then, in her junior year of high school, she studied physics with a teacher so in love with the subject that Chipps fell in love with it, too. She dropped biology in her senior year, opting to take a more advanced, calculus-based physics course and has never looked back.

Chipps is one of four young researchers from ORNL to receive a 2017 Early Career Research Program award from DOE’s Office of Science. She studies rare nuclei typically found only within exploding stars. She and her colleagues use beams of these nuclei produced at radioactive ion beam facilities. One such facility is DOE’s Facility for Rare Isotope Beams, currently under construction at Michigan State University.

FRIB is the focus of Chipps’ 2017 Early Career Research Program proposal, titled “Next-Generation Particle Spectroscopy at FRIB: A Gas Jet Target for Solenoidal Spectrometers.” In this project she will work to overcome challenges in designing targets for nuclear reaction studies planned at the facility.

Chipps holds a bachelor’s degree in engineering physics and a Ph.D. in applied physics from the Colorado School of Mines and has been an ORNL Liane B. Russell Fellow since spring 2015. We talked with her about her work and about what drew her to science. This is an edited transcript.

What do we learn from radioactive ion beam facilities?

One of the outstanding questions in nuclear physics today is the origin of the elements. We have to understand the abundance patterns that we observe in the universe, and to do that we have to understand nuclear reactions that are taking place on stable and unstable nuclei. In explosive astrophysical events like supernovae, these unstable nuclei are being produced in tremendous numbers. And those are actually affecting the stable nuclei that we see on earth.

So we want to be able to study unstable nuclei, which means we have to produce them somehow in the laboratory. This is where radioactive ion beam facilities come in. A radioactive ion beam facility produces these exotic unstable nuclei and quickly delivers them to our experimental instruments, where we’re able to study them.

What challenges are you working to overcome at FRIB?

There are three main ingredients to doing a nuclear reaction study. First is the radioactive ion beam. Second is the suite of detectors that we use to observe the reaction products. And third is the target, which is the material we use to induce the nuclear reaction of interest. In astrophysical events like supernovae, you have a lot of hydrogen and helium, and we’re having a lot of nuclear reactions taking place on those elements. So we want to produce a target of those gases.

Previously I worked to develop a supersonic gas jet target to improve how we’re able to study radioactive ion beam measurements. What I’d like to ask now is: Can we take that optimized target and combine it with other state-of-the-art devices to further improve these nuclear reaction studies? This Early Career award is going to provide me the opportunity to see if we can combine a gas jet with a solenoidal magnetic field to improve the resolution and the signal to noise that we get in measurements of this type.

Why is this work important?

Let’s take an example. In a supernova explosion, a lot of the synthesis of the elements we see passes through a particular unstable isotope: nickel-56. Nickel-56 is produced in abundance in supernovae, and yet we don’t actually know very much about it experimentally. I’d like to take advantage of these advances in instrumentation to study the properties of nickel-56 and better understand to what extent it affects the supernova explosion. This will allow us to understand how that explosion is producing the elements that we see around us.

What made you choose a career in science?

I like to think of myself as a pretty even left brain/right brain kind of person, so when I got to the end of high school, I was faced with the decision of which of my many interests to pursue. I figured that it would be easier to be a scientist with a music hobby than a musician with a science hobby, so here I am.