Electron Screening in Metal Deuterides: Measurement Systematics, Evolving Target State, and an Experimental Arbitration Protocol (SCREEN-PROG-04)

Screening parameters inferred from low-energy nuclear yields in metal deuterides depend on the target's preparation and on its acquisition history: the beam changes the target it measures. This paper separates the instantaneous screening of the target state, a yield-equivalent value within one acquisition interval, and a global constant-model fit to an energy sweep.

Fully specified synthetic examples show that the order in which energies are taken, together with a fitted normalization, can move a constant fit outside the physical range: above the endpoint for a high-to-low sweep, below the starting value for a low-to-high sweep. The drift models are identifiable but badly conditioned in a single sweep; returning over the same energies cuts the start-value error four- to fivefold at the same total fluence.

The paper proposes charge-normalized, rapidly interleaved two-energy measurements at controlled accumulated fluence, with an uncertainty budget of about 7.2 eV per dose step, plus independent materials and proton-spectrum diagnostics. A third interleaved energy adds a conditional curvature test, with an expected separation of about 4 standard deviations from a homogeneous target for a 150 eV screening spread (2.7 to 4.6 depending on how the stopping-power error is shared), but a screening spread and an additive thermal plateau give the same two ratios, so the plateau must be constrained separately.

The paper also reads the Project Callisto calorimetry record (2026) as a systematics precedent and discusses recent beam-target work from Szczecin and UC Davis/LBNL. It reports no new nuclear data; every computed number and figure is reproduced by the scripts in the accompanying archive. The 3D mixer is an interactive explorer of the paper's six results.

AI-assisted: AI tools were used for literature search, computation and drafting; the author directed the work and takes responsibility for its content.