ODeSA and the ¹⁸O(α,n)²¹Ne Reaction

Rebecca Toomey
Graduate Student
Rutgers University

Nuclear reaction data is crucial in many aspects of nuclear physics. Its applications vary, from nuclear fission reactors to simulating stellar nucleosynthesis. Following WWII, accelerator facilities were plentiful and were producing an abundance of high quality data. However, data for neutron-emitting reactions, such as (α, n), were limited by neutron de- tection technology at the time. Though there are richly-detailed total cross sections available, for many reactions there are no partial cross sec- tions or branching ratio information. As an example, the ¹⁸O(α,n)²¹Ne only has one measurement of the partial cross section at low energies but this data would have a broad interest across nuclear physics. For exam- ple, in nuclear nonproliferation, this reaction acts as a neutron source for low burnup uranium oxide fuel. The newly developed ORNL Deuterated Spectroscopic Array (ODeSA) utlizes the spectrum unfolding method of neutron spectroscopy, and was recently used to measure the ¹⁸O(α,n)²¹Ne reaction at the University of Notre Dame’s 5U accelerator over the range Eα = 2 − 8 MeV. In addition to neutron spectroscopy with spectrum unfolding, 2 HPGe detectors from the LANL GEANIE array were fielded in order to measure secondary gamma rays. Combining these 2 detec- tion methods allows for the ability to independently measure the partial cross sections from the ¹⁸O(α,n)²¹Ne reaction. This presentation will fo- cus on the characterization of ODeSA as well as preliminary partial cross sections and analysis from the measurement of the ¹⁸O(α,n)²¹Ne reaction.

This work is supported in part by the U.S. Department of Energy Steward- ship Science Academic Alliances and Office of Nuclear Physics and the National Science Foundation.

Hosted by Prof. Wiescher

Presented both in-person and via zoom. Please email nsladmin@nd.edu for zoom link.