Lab scientist wins Springer Thesis Award for work in neutrino research

Sam Hedges sits inside the nEXO neutirno detector (Download Image)

LLNL postdoc Sam Hedges sits inside the high voltage test bed (referred to as LXTS) for nEXO experiments.. (Photos by Blaise Douros)


Lawrence Livermore National Laboratory (LLNL) postdoc Sam Hedges has won a 2024 Springer Thesis Award for his work in searching for the elusive neutrino.

“I’m honored that my thesis was nominated for this award, and was excited when I found out it had won,” Hedges said.

His thesis, “Low Energy Neutrino-Nucleus Interactions at the Spallation Neutron Source," highlights the development and analysis of multiple neutrino detectors deployed to the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory as part of the COHERENT experiment. His thesis will be published in a book series: "Springer Theses: Recognising Outstanding Ph.D. research."

Neutrinos are one of the most abundant particles in the universe. However, they are notoriously difficult to detect. Despite the first successful detection of neutrinos nearly 70 years ago, many of their fundamental properties are still unknown.

“Some of these properties disagree with predictions from the Standard Model of particle physics, so they are a promising channel to search for new physics,” said Hedges, who works in LLNL’s particle physics group. “Because neutrinos interact so infrequently, they can travel long distances carrying information about the processes that generated them, and we can use them to study those processes.”

Neutrinos are created in many different reactions: in nuclear reactors, from beta decay of nuclei in the Earth, from nuclear fusion inside the sun and in core-collapse supernovae.

In a supernova, ~99% of the star’s gravitational binding is released in the form of neutrinos. This can generate an intense burst of neutrinos over a short period of time that scientists can look for with detectors on Earth.

“The neutrinos emitted by the supernova can arrive at Earth ahead of the light produced by a supernova, giving an early warning to astronomers to look for a supernova,” Hedges said. “Neutrinos at the Spallation Neutron Source are produced at a very similar energy range to those produced by supernovae, so it is a useful place to study neutrino scattering at supernova energies.”

LLNL postdoc Sam Hedges adjusts hardware on the high-voltage test bed for nEXO.

His current work focuses on the nEXO experiment, which is searching for neutrinoless double beta decay. His work involves testing high-voltage hardware for the nEXO experiment using a large xenon detector located at LLNL. nEXO is an international collaboration, with LLNL being the lead national laboratory for the experiment.

Hedges graduated with his Ph.D. from Duke University and came to the Lab because he was interested in working in neutrino, nuclear and particle physics research.

“nEXO will be one of the most sensitive detectors searching for neutrinoless double beta decay, which has the potential to provide us with new knowledge on the nature of the neutrino and the universe we live in.” Hedges said. “Outside of nEXO, I’m interested in the cutting-edge research at LLNL developing new neutrino detectors, searching for sterile neutrinos, measuring the neutrino mass and searching for dark matter.”

The series “Springer Theses” brings together a selection of the very best Ph.D. theses from around the world and across the physical sciences. Nominated and endorsed by two recognized specialists, each published volume has been selected for its scientific excellence and the high impact of its contents for the pertinent field of research.

Springer is a global publishing company that publishes books and peer-reviewed journals in science, humanities, technology and medicine.