Welcome to 3Q4, in which we put a few questions to someone from our staff to help get to know the people behind the science. In this issue, we meet Tianhuan Luo, a research scientist in the Berkeley Accelerator Controls and Instrumentation Program (BACI).
Her interest in science kindled in childhood by thought-provoking science fiction, Tianhuan studied physics at the University of Science and Technology of China in Hefei, then went to Indiana University for graduate work under S.Y. Lee.
Her interests include radiofrequency (RF) design and its intersection with advanced computer modeling, including artificial intelligence and machine learning (AI/ML). Among other endeavors, she is principal investigator of a Laboratory-Directed R&D project that applies multi-objective genetic algorithms to the complex task of optimizing the design of RF cavities.
You had an interesting journey from China to Indiana and ultimately Berkeley Lab. Can you tell us what attracted you to physics, and what brought you here?
I enjoyed reading science fiction when I was little. It was from those stories that I first heard about quantum mechanics, entropy, wormholes, and so forth. They were mysterious and fascinating. One of my favorite books was Ted Chiang‘s 1998 novel Story Of Your Life, the one they made into the movie Arrival a few years ago.
I start taking physics classes at school in 8th grade. Since then, physics has no longer been a matter just of fancy concepts but also of numbers, equations, and rigorous logic. It also meant lots of homework and exams. Luckily, I did not badly in those exams, which boosted my confidence and my affection towards physics, though my idea of what “physics” might be was still very primitive at that time.
In college I was majoring in chemistry in my freshman year, but later switched to physics, answering the calling of “Schrodinger’s cat” and the “twin paradox” from my childhood SF reading. College involved a lot more classes with hands-on experiments than high school, and I had great fun with that. My thesis project was on making luminescent thin films with rare earth materials.
“In accelerators, there are so many things you can do in experiment as well as in theory. It’s good to have a solid and broad foundation.”
After earning my bachelor’s degree in 2006 at USTC, I wanted to see some of the world and try serious research work, so I went to graduate school at Indiana University. I first went into condensed matter theory — specifically, the quantum state of 2D materials such as graphene. It was an exciting area, but I still felt like doing something more hands-on. At that time, IU was building a small electron accelerator for radiation testing, as well as to explore the inverse Compton scattering in a low energy storage ring. So I switched to this project and joined S.Y.’s group, and started my journey on particle accelerators.
I visited CBP for two weeks in 2010 to learn how to design a traveling-wave kicker that we needed for the storage ring at Indiana. I met and worked with Stefano de Santis, Derun Li, John Byrd, John Staples and others. Everyone was super nice. I also enjoyed the beautiful views on the hill and the delicious foods around downtown. So when there came a postdoc position on the Muon Ionization Cooling Experiment (MICE), supported by Don Summers at the University of Mississippi but based at Berkeley, I jumped in immediately.
I then did another postdoc, this time working directly for Berkeley Lab, and was hired as a Research Scientist in 2015. My work at the Lab started with building components for MICE. Later I was involved in other projects such as PIP-II (the Proton Improvement Plan for a high-intensity accelerator for neutrino experiments at Fermilab), LCLS-II (the Linac Coherent Light Source upgrade at SLAC), and Berkeley Lab’s own Advanced Light Source Upgrade. In recent years my work has mainly focused on the design and analysis of RF components, RF measurements and tests, and simulation of electromagnetic fields for other components such as kickers and beam position monitors.
If this chimes with a young person who is thinking about a physics career, what advice would you give?
Do the best you can in the core physics classes (classical mechanics, electrodynamics, quantum mechanics and thermodynamics) and the core math classes (calculus, complex analysis, differential equations). This builds a strong foundation for your future work. Keep an open mind and be willing to try something you haven’t done before or are not familiar with.
For students particularly interested in RF design, electrodynamics and differential equations are particularly important. Also, nowadays RF design relies more and more on computation, so good coding skill will be a big plus.
In accelerators, there are so many things you can do in experiment as well as in theory. It’s good to have a solid and broad foundation.
A great way to advance your education is the US Particle Accelerator School. I have been both as a student and as an instructor and enjoyed it a lot. Even though it is only two weeks long, it is very concentrated and one can learn a lot. It is also a good opportunity to catch up with old friends and meet new ones. From time to time, USPAS offers on-site classes at accelerator labs, where students can learn with real accelerators. These fill up quickly, and I was very lucky to have such a class at the Jefferson Lab energy-recovery linac in 2011.
How does an experimental scientist’s day play out in COVID times?
Since the delivery of the LCLS-II injector gun, my work has focused mainly on simulation and analysis, as well as AI/ML, so the COVID work-from-home scenario hasn’t impacted my work very much so far. I only go back onsite once a while to check our computation server. There might be some hardware work coming in soon. We will see. Regardless of the type of work, I prefer to get back to lab and meet people face to face like before.