The neutron transmission spectrum through a high-purity \(^{238}\) U slab (dimensions: 100 mm \(\times\) 100 mm \(\times\) 20 mm) irradiated by a broad-spectrum neutron field was measured at \(0^\circ\) using the time-of-flight (TOF) method. The experiment was carried out at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou at the Institute of Modern Physics, Chinese Academy of Sciences. Broad-spectrum neutrons were generated by bombarding a tungsten target with 80.5 MeV/u \(^{12}\) C ions. GEANT4 calculations were performed under the same experimental conditions by combining the INCL++, BIC, and BERT physics models with the evaluated nuclear data libraries ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0. The calculations reproduce the measured spectrum reasonably well over most of the investigated energy range; however, they overestimate the data below 10 MeV and tend to underestimate the measured yield above 70 MeV. The present results provide benchmark information for validating neutron-transport simulations relevant to accelerator-driven systems.
