Cause of the 198Au isomeric-ratio deviation reported by Capurro et al.

Identify the cause of the systematic deviation in the isomeric ratio of 198Au reported by Capurro et al. for the nat Pt(α,x)198Au reaction relative to the results of Hermanne et al. and the present measurements, given that Capurro et al. adopted the same 215 keV gamma-ray emission probability (76.9%) as used in the present analysis.

Background

In comparing measured excitation functions and isomeric ratios for nat Pt(α,x)198Au, the authors find overall consistency between their results and those of Hermanne et al., particularly when proper treatment of the correction factor in the ground-state subtraction is applied.

However, the metastable-state production cross sections and derived isomeric ratios reported by Capurro et al. are systematically lower, despite Capurro et al. using a 215 keV gamma-ray emission probability consistent with the value adopted in this work. This leaves the origin of the discrepancy unresolved and motivates clarifying analyses or re-measurements to reconcile datasets.