Constraining Neutron Capture Cross Sections for Unstable Nuclei with Surrogate Reaction Data and Theory

Area of Science:

• Nuclear Physics
• Nuclear Astrophysics
• Nuclear Energy Science

Background:

• Reliable nuclear reaction data on unstable isotopes are essential but challenging to obtain.
• Neutron capture cross sections are critical for astrophysical models, national security, and nuclear energy simulations.
• Measuring these cross sections is particularly difficult when both the projectile and target nuclei are unstable.

Purpose of the Study:

• To demonstrate a new indirect ('surrogate') method for determining neutron capture cross sections on unstable isotopes.
• To validate the developed method through a benchmark experiment measuring the known ^{90}Zr(n,γ) cross section.
• To establish a generalized approach applicable to a wider range of nuclear reactions and experimental setups.

Main Methods:

• Employed an indirect measurement technique, referred to as the 'surrogate' method.
• Combined the surrogate measurement with theoretical calculations to determine cross sections.
• Validated the method by performing a benchmark experiment on the stable ^{90}Zr(n,γ) reaction.

Main Results:

• Successfully demonstrated a new method for measuring neutron capture cross sections on unstable isotopes, using ^{87}Y(n,γ) as a prototype.
• Validated the indirect method by accurately reproducing the known ^{90}Zr(n,γ) cross section.
• Showcased the generalizability of the approach for various nuclear reactions.

Conclusions:

• The developed indirect ('surrogate') method provides a viable solution for obtaining crucial neutron capture cross section data on unstable isotopes.
• This technique can be implemented in both traditional stable-beam experiments and inverse kinematics at rare-isotope facilities.
• The method offers a significant advancement for nuclear science, impacting fields from astrophysics to nuclear energy and security.