HZETRN radiation transport validation using balloon-based experimental data.

Area of Science:

• Space physics
• Radiation transport modeling
• Astroparticle physics

Background:

• NASA's High charge (Z) and Energy TRaNsport (HZETRN) code models cosmic radiation effects.
• Accurate radiation transport is crucial for astronaut and instrument safety in space.

Purpose of the Study:

• To validate HZETRN's computed differential flux against balloon-based experimental measurements.
• To quantify model uncertainties and identify systematic biases in HZETRN predictions.

Main Methods:

• Compared HZETRN flux calculations with data from three balloon experiments.
• Utilized an interval-based validation metric accounting for flux and energy uncertainties.
• Analyzed uncertainty distributions and computed metrics for data subsets (experiment, particle type, energy).

Main Results:

• HZETRN generally showed good correlation with measurements, with a median relative difference of 30%.
• Model uncertainties were broad, with ~30% exceeding ±40%.
• HZETRN systematically under-predicted measurements (~80% negative relative uncertainties), notably for alpha particles and protons below 2.5 GeV/u.

Conclusions:

• HZETRN requires improvements, particularly in light ion production cross sections, to enhance accuracy.
• Systematic biases were identified for specific particle types and energy ranges, necessitating further investigation.
• The validation metric effectively revealed trends in HZETRN's predictive performance across diverse conditions.