Systematic study on sputtering yields by 14.9 MeV neutrons

Neutron sputtering yields have been measured for radioactive nuclide production reactions at a 14.9 MeV neutron energy. Materials investigated were F, Mg, Al, Sc, Ti, V, Cr, Fe, Co, Ni, Cu, Zr, Nb, Mo, Pd, Ag, Cd, In, Ta, Re, Pt, Au, Pb and SS316. The 14.9 MeV neutrons were produced by a D-T neutron generator at the Fusion Neutronics Source (FNS). The sputtered radioactive materials deposited on the collectors were investigated by the neutron activation analysis. In this work, all measurements were performed in air. Several different distances between the sample and the collector of the sputtered materials were chosen to be 0.2, 0.5, 1.0, 2.0, 3.0 and 5.0 mm to deduce the sputtering yield. The sputtering yields of fifty-seven reactions belonging to (n, 2n), (n, α), (n, p) and (n, np) have been measured. The systematics for reduced sputtering yield as a function of the atomic number (Z) have been derived for (n, 2n), (n, α), (n, p) and (n, np) reactions. A simple power function RSn=aZb was very good to describe the systematics, where the parameters a and b were fitted according to the type of reactions. Most of the deviations between measured values and the systematic results are within a range of 25 %. Backward sputtering yields were lower by a factor of 1.5 to 180 than forward ones. The present results are discussed along with others experimental results and calculation results. (author). 57 refs