First Measurement of the Total Neutron Cross Section on Argon between 100 and 800 MeV

Area of Science:

• Nuclear Physics
• Particle Physics

Background:

• Neutron-argon interactions are crucial for understanding nuclear reactions and detector physics.
• Previous measurements of neutron cross sections on argon are limited, especially at intermediate energies.

Purpose of the Study:

• To report the first measurement of the neutron cross section on argon in the 100-800 MeV energy range.
• To compare experimental results with predictions from GEANT4 and FLUKA simulations.

Main Methods:

• Utilized the Mini-CAPTAIN detector with a 4.3-hour exposure to the WNR/LANSCE beam at Los Alamos National Laboratory (LANL).
• Measured the total cross section by analyzing neutron flux attenuation through liquid argon.
• Reconstructed 2631 candidate interactions using custom algorithms for time projection chamber data, with neutron kinetic energy determined by time-of-flight.

Main Results:

• The energy-averaged neutron cross section on argon was determined to be 0.91±0.10(stat)±0.09(syst) barns.
• This experimental value is higher than the simulated cross sections from GEANT4 (0.60 b) and FLUKA (0.68 b) in the same energy range.

Conclusions:

• The measured neutron cross section on argon provides essential data for nuclear models and detector simulations.
• Discrepancies between experimental data and event generator predictions highlight the need for refined theoretical models and simulation parameters.