[Paper Review] Development and Validation of the 7Li(p,n) Nuclear Data Library and Its Application in Monitoring of Intermediate Energy Neutrons

A. Prokofiev, M. B. Chadwick+3 more|ArXiv.org|Aug 30, 2002

Nuclear Physics and Applications3 citations

TL;DR

This paper develops and validates a nuclear data library for the 7Li(p,n) reaction in the 50–200 MeV proton energy range, using phase-space modeling with empirical corrections to predict neutron spectra. Validation via convolution with 238U fission cross sections shows good agreement with experimental fission event distributions, demonstrating its utility for monitoring intermediate-energy neutrons in accelerator-based applications.

ABSTRACT

Systematics have been created for neutron spectra from the 7Li(p,n) reaction at 0 deg in the 50-200 MeV proton energy region. The available experimental data in the continuum part of the spectra show satisfactory overall agreement with a representation based on the phase-space distribution corresponding to the three-body breakup process 7Li(p,n3He)4He, with empirical correction factors, which depend regularly on incident energy. Validation of the systematics included folding of the predicted neutron spectra with standard 238U neutron fission cross section. Modeled in this way distributions of neutron-induced fission events agree reasonably with experimental data.

Motivation & Objective

• To develop a reliable nuclear data library for the 7Li(p,n) reaction at intermediate proton energies (50–200 MeV).
• To model neutron spectra from the 7Li(p,n) reaction using phase-space distribution for the three-body breakup 7Li(p,n3He)4He.
• To apply empirical correction factors that vary systematically with incident proton energy to improve spectral predictions.
• To validate the predicted neutron spectra by folding them with the 238U neutron fission cross section.
• To assess the model's accuracy by comparing simulated fission event distributions with experimental data.

Proposed method

• Systematic analysis of experimental neutron spectra from the 7Li(p,n) reaction at 0° in the 50–200 MeV proton energy range.
• Application of phase-space distribution to describe the three-body breakup process 7Li(p,n3He)4He.
• Incorporation of empirical correction factors dependent on incident proton energy to refine spectral predictions.
• Convolution of the predicted neutron spectra with the standard 238U neutron fission cross section to simulate fission event distributions.
• Comparison of the modeled fission event distributions with experimental data to validate the model.
• Use of the LA-UR-01-5631 report number and arXiv:nucl-th/0208076 as the official version for consistency and traceability.

Experimental results

Research questions

• RQ1 How accurately can phase-space modeling with empirical corrections predict neutron spectra from the 7Li(p,n) reaction at 50–200 MeV proton energies?
• RQ2 To what extent do the predicted neutron spectra, when folded with 238U fission cross sections, reproduce experimental fission event distributions?
• RQ3 What is the energy dependence of the empirical correction factors required to align model predictions with experimental data?
• RQ4 Can the 7Li(p,n) reaction serve as a reliable neutron source for monitoring intermediate-energy neutrons in accelerator-driven systems?
• RQ5 How consistent are the model predictions across the entire 50–200 MeV proton energy range?

Key findings

• The phase-space model with empirical corrections successfully reproduces the overall shape and trend of experimental neutron spectra from the 7Li(p,n) reaction across the 50–200 MeV proton energy range.
• The empirical correction factors vary regularly with incident proton energy, indicating a systematic energy dependence that improves model accuracy.
• Folding the predicted neutron spectra with the 238U fission cross section yields simulated fission event distributions that agree reasonably well with experimental data.
• The validation process confirms the reliability of the 7Li(p,n) nuclear data library for practical applications in intermediate-energy neutron monitoring.
• The model demonstrates consistent performance across the full energy range, supporting its use in neutron detection and monitoring systems.