Improved RBS characterization of TiN nuclear targets using a thick Ti interlayer

Accurate Ti/N atomic ratios are required for cross-section measurements of the 14 N ( p , γ ) 15 O reaction. We fabricated TiN/Ti/Si reference samples and corresponding TiN/Ti/Ta reaction targets by filtered cathodic vacuum arc deposition. A thick Ti interlayer shifted the Si substrate signal to lower energies, creating a low-background window for nitrogen analysis. Rutherford backscattering spectra measured with a 3.15 MeV 7 Li 2 + beam were analysed using SIMNRA. The fitted areal densities of the Ti interlayer and TiN layer were 5118.742 × 1 0 15 and 951 × 1 0 15 atoms cm −2 , corresponding to equivalent thicknesses of about 903 and 94 nm, respectively. Constrained-profile analysis yielded a Ti/N atomic ratio of 0.93 4 − 0.028 + 0.021 , including stopping-power, Ti-interlayer areal-density, and normalization effects. Three additional experimental contributions gave a first-order GUM/RSS standard uncertainty of 0.010; quadrature combination produced 0.93 4 − 0.030 + 0.023 . A 1998 keV proton spectrum served only as a consistency test and was excluded from the Ti/N determination. These parameters support propagation of target-composition uncertainty into effective proton stopping power and astrophysical S -factor measurements.