UTRIP 2023 in the Yokoyama-Nakajima Lab

by Emma Codianne

My supervisor, Dr. Nakajima, and I at the UTRIP closing ceremony.

This summer, with the generous help of Friends of UTokyo, Inc., I have been incredibly fortunate to participate in the University of Tokyo Research Internship Program (UTRIP) with the Yokoyama-Nakajima Group. I am currently a third-year student at Rice University in Houston, Texas, USA majoring in Physics. I was incredibly excited for this opportunity to work and study at the University of Tokyo, as it was my first time visiting Japan and I was able to learn about novel physics research. During my 6-week stay with UTRIP, I worked at UTokyo’s Hongo campus, under the supervision of Dr. Yasuhiro Nakajima. The Yokoyama-Nakajima Group researches experimental particle and astroparticle physics, a specialization I have not previously worked in. At Rice, I am conducting research in experimental condensed matter with the Morosan Group, focused on the synthesis and study of quantum materials with emergent properties such as superconductivity and spin textures.

The GAGG scintillator crystal,
composition (Gd0.99CeO0.01)3Al2Ga3O12,
used in my research for the 0νββ search.

When I heard about the UTRIP program, I immediately knew I wanted to apply because it had been my dream to study abroad and the opportunity to conduct my own research at the University of Tokyo, a place consistently at the forefront of physics research, was incredible. I was interested in working with the Yokoyama-Nakajima lab because of their research regarding neutrino physics, notably with the Super-Kamiokande neutrino detector. My research over the course of UTRIP centered around testing the GAGG scintillator crystal as part of the search for the phenomenon of neutrinoless double beta decay (0νββ). In short, I analyzed the radioactive impurity of this crystal in hopes of reducing its background noise to observe neutrinoless double beta decay in the future. Neutrinoless double beta decay has never been seen before, but its observation would prove the hypothesis that the neutrino is a Majorana fermion—a particle that is its own antiparticle. Through my UTRIP research, I learned much about particle physics, equipment used in the lab’s work (e.g. photomultiplier tubes), and data analysis methods.

My visit to Super-Kamiokande.

One of the most memorable parts of UTRIP for me was visiting the Super-Kamiokande site in Kamioka, Gifu prefecture with my supervisor, Dr. Nakajima. Going into the mines and seeing the control room of Super-K in person was truly amazing, and I am so grateful for the opportunity to have visited the place where neutrino oscillation was proven back in 2015. I also got to see how gadolinium was added to Super-K’s water tank back in 2020 for the new SK-Gd observation to improve measurements and sensitivity for neutrino interactions.

Outside of the lab, I enjoyed every cultural immersion experience that UTRIP graciously provided, my favorite being our trip to the historic Shunkaen Bonsai Museum where I got to partake in a traditional Japanese tea ceremony and don yukata in the bonsai garden. On another cultural excursion, us UTRIP students were able to watch an incredible kabuki performance at Kabukiza Theater in Ginza, followed by lunch in Asakusa with views of the beautiful Sensoji Temple. These experiences learning about Japanese culture were once in a lifetime and made me appreciate my time in Tokyo and the opportunity to immerse myself in a new culture.

My friends and I at Shunkaen Bonsai Museum.

I’m very grateful for the friends I made from UTRIP, both inside and outside of the lab. I enjoyed getting to know my fellow UTRIP cohort, meeting new people from all around the world. I also loved spending time with the graduate students in the Yokoyama-Nakajima lab, and am grateful for their kind welcome and help whenever I had questions.

My stay at the University of Tokyo went by too fast, but I am so grateful for the opportunity to learn under Dr. Nakajima and conduct research with the Yokoyama-Nakajima Group. I am also incredibly thankful to FUTI, since none of this amazing summer would have been possible without their generous support.