National Superconducting
Cyclotron Laboratory

Kyle Brown
Kyle Brown
Assistant Professor of Chemistry
Nuclear Chemistry
BS, Chemistry, Indiana University, 2012 PhD, Nuclear Chemistry, Washington University in St. Louis, 2016
Joined NSCL in 2016
Phone 517-908-7267
Office 2021

Kyle Brown

Students in my group will use nuclear reactions to probe how nuclear matter assembles in systems ranging from nuclei to neutron stars. This work is split between two main concentrations: utilizing reactions to determine the nuclear equation of state and to probe the origin of the elements.

After the groundbreaking measurement of a neutron-star merger two years ago, there has been a renewed interest in pinpointing the nuclear equation of state for matter about twice as dense as found in the middle of heavy nuclei. In particular, we seek to understand the density and momentum dependence of the symmetry energy. This is a repulsive term in the binding energy that arises from an imbalance in the numbers of protons and neutrons. Using heavy-ion collisions, my group can create these very dense environments in the laboratory, and by studying the particles that are ejected from the collision we can help determine the symmetry energy.

My second research focus is on probing the origin of the elements. All elements heavier than iron are made via proton or neutron capture reactions in explosive stellar environments, for example neutron-star mergers or x-ray bursts. Many of these reactions have extremely low cross sections and cannot be measured directly. Students in my group will use transfer reactions to measure the nuclear structure of these rare isotopes, to indirectly constrain their nucleon capture cross sections.

These experiments are typically performed using small arrays of silicon and cesium-iodide detectors. Quite often we will use the High-Resolution Array (HiRA), which is a modular array of telescopes made of a combination of one to two silicon detectors followed by four cesium- iodide detectors arranged in quadrants behind them. These telescopes provide excellent energy and angular resolution, and the combination of detectors determines the identity of the charged particle. These detectors are often paired with neutron detectors, gamma detectors, and/or the S800 spectrometer.

Students in my group will take leading roles in the setup, execution, and analysis of these experiments. This can include design and testing of new detector systems, computer simulations of the experiment, or theoretical modeling depending on the interests of the student. Future experiments include using nuclear structure inputs to constrain the neutron skin in heavy nuclei, transfer reactions to study the origin of the elements, and measuring transverse and elliptical flow observables from heavy-ion collisions.

Selected Publications

First observation of unbound 11O, the mirror of the halo nucleus 11Li. T.B. Webb et al. PRL 112, 122501 (2019).

Large longitudinal spin alignment generated in inelastic nuclear reactions. D.E.M. Hoff et al. PRC 97, 054605 (2018).

Observation of long-range three-body Coulomb effects in the decay of 16Ne. K.W. Brown et al. PRL 113, 232501 (2014).