Neutron capture reactions on ⁴⁴Ti relevant for core-collapse supernovae

Signatures of short-lived radioisotopes such as ⁴⁴Ti (T_1/2 = 60 years) originating in explosive stellar environments such as core-collapse supernovae (CCSNe) have been observed using satellite-based gamma-ray observatories. In order to improve theoretical CCSN models, nuclear physics inputs such as nuclear reaction rates need to be constrained. This includes characterizing the reactions that both produce and destroy ⁴⁴Ti at the relevant temperatures, in which the neutron-induced destruction paths can be measured directly using radioactive targets at facilities that can produce sufficiently high quality neutron beams. Using a radioactive target of ⁴⁴Ti and an intense neutron beam covering a broad range of fast neutron energies at the Los Alamos Neutron Science Center (LANSCE) facility at Los Alamos National Laboratory, ⁴⁴Ti(n,p) reaction cross sections have been measured. Preliminary reaction cross sections, along with proposed improvements for future measurements will be presented. This includes some highlights of the development of a solenoid spectrometer at LANSCE for further optimized measurements using radioactive targets.

This work benefits from the LANSCE accelerator facility and is supported by the U.S. Department of Energy under contracts DE-AC52- 06NA25396, the Laboratory Directed Research and Development program of Los Alamos National Laboratory under project number 20230534ECR, and the U.S. Department of Energy Office of Science-Nuclear Physics.