Verification of a Hill–Wheeler Statistical Fission Model Using ENDF/B-VIII.0 Data and a Reproducible Python Implementation for Charge-Yield Calculations

This Zenodo deposit provides the manuscript “Verification of a Hill–Wheeler Statistical Fission Model Using ENDF/B-VIII.0 Data and a Reproducible Python Implementation for Charge-Yield Calculations,” together with a reproducible workflow description for charge-yield analysis. The study re-implements a Selective Channel Scission (SCS) statistical fission model augmented by Hill–Wheeler penetrability, interpreting the Hill–Wheeler logistic form as a quantum-statistical distribution analogous to the Fermi–Dirac function, and validates the approach against evaluated charge-yield data from ENDF/B-VIII.0. 

We analyze nine actinides (232Th, 233U, 235U, 238U, 237Np, 239Pu, 240Pu, 242Pu, and 241Am) under three incident-neutron conditions (thermal, 500 keV, and 14 MeV, where applicable). The calculated charge yields Y(Z) reproduce the evaluated distributions with good agreement across the considered cases.  

From a two-stage fitting procedure, we extract an effective fission distance dw(Z) and a channel-dependent “Fermi energy” correction Ex(Z). To stabilize Ex(Z) in the low-yield tails, the implementation applies low-yield filtering (excluding points with Yexp(Z) below a threshold) and an optional nuclide-dependent Z-range cutoff. 

For barrier-scale interpretation, the manuscript defines a low-energy average of the maximum Ex values using thermal and 500 keV cases, while treating 14 MeV as a separate high-excitation reference. The workflow is designed for transparency and reproducibility, with explicit inputs (CSV yield tables and mass data) and explicit outputs (per-case parameter CSVs and figures).  

A reproducible Python project (inputs, notebooks, and output figure templates) is provided alongside this manuscript; a public repository link may be added by the author when finalized. 

Update (manuscript revision):
The revised manuscript improves the reproducibility of the two-stage fitting procedure by making the second-step smoothing of the effective scission distance fully explicit and by reporting the corresponding fit parameters for all analyzed nuclide and incident-energy combinations in a dedicated table. The updated results show that the extracted symmetry parameter remains essentially consistent with charge conservation across all cases, supporting a physically coherent Coulomb-geometry interpretation of the effective distance scale.

The revision also clarifies the barrier-scale discussion by defining the low-energy reference using only thermal and five-hundred-keV results, while treating fourteen-MeV cases separately as high-excitation benchmarks.