Description: This article discusses elastic and inelastic scattering of 1.5-MeV neutrons by the even-A isotopes of zirconium and molybdenum. Abstract: Differential elastic and inelastic cross sections were measured for 1.5-MeV neutrons scattered by the even-A isotopes of zirconium and molybdenum. The scattering samples were enriched isotopes of ⁹⁰Zr, ⁹²Zr, ⁹⁴Zr, ⁹²Mo, ⁹⁴Mo, ⁹⁶Mo, and ¹⁰⁰Mo. The cross sections were measured using a dynamically biased neutron time-of-flight spectrometer. The differential cross sections have root-mean-square relative and normalization uncertainties of 2 to 3.5% and 7 to 7.5%, respectively, for elastic scattering, and 6 to 13% and 9 to 15%, respectively, for inelastic scattering. Isotopes with similar level structures have almost identical elastic angular distributions. The entire set of data was theoretically fitted using the optical-statistical model with resonance-width-fluctuation corrections. The calculated elastic differential cross section was assumed to be an incoherent sum of shape-elastic and compound-elastic scattering. At the minima in the angular distributions the cross sections were dominated by compound-elastic scattering.

Description: This article discusses K-shell x-ray production cross sections of selected elements from Ti to Y. Abstract: K-shell x-ray production cross sections and Kβ/Kα ratios have been measured for thin targets of Ti, V, Cr, Fe, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, and Y for 0.5- to 2.5-MeV alpha particles. The experimental values are compared to the nonrelativistic plane-wave Born approximation (PWBA), the binary-encounter approximation, and the PWBA with binding energy and Coulomb deflection corrections. The PWBA with corrections provides the best agreement with the experimental cross sections.

Description: This article discusses K-shell ionization elements Ca to Zn for 0.5 to 2.5-MeV/amu 14N-ion bombardment. Abstract: Target K-shell x-ray production cross sections, x-ray energy shifts, and Kβ/Kα ratios have been measured for 7-35-MeV 14N ions on thin solid films of Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn. Comparisons of the data were made with theoretical predictions obtained from the binary-encounter approximation and the planewave born approximation (PWBA). These theories were found to overpredict the experimental data by a factor of 10 at the lower energies. However, at the lower energies, the PWBA, with modifications for increased target electron binding, Coulomb deflection, target electron polarization, and relativistic effects produced results in good agreement with the experimental data was found which increases as the ratio of Z1/Z2 becomes larger. Corrections to the fluorescence yields attributable to multiple ionization processes and the addition of electron capture contributions to the previously indicated direct ionization theories produced results in excellent agreement with the experimental data with the exception of those for the light elements at the highest energies.

Description: This article discusses K-shell x-rays of selected elements from Nb through Gd for incident protons and alpha particles from 0.6 to 2.4 MeV. Abstract: K-shell x-ray production cross sections and Kβ/Kα ratios are presented for 0.6- to 2.4-MeV protons and alpha particles incident on thin targets of selected elements from Nb to Gd. The Kβ/Kα ratios are compared to the theoretical predictions of Scofield and agree within 10%. The experimental cross sections are compared to the theoretical predictions of the plane-wave Born approximation (PWBA) and the PWBA modified to include binding energy, Coulomb deflection, and relativistic effects. It is seen that the PWBA modified for binding energy and Coulomb deflection effects agrees with the experimental data for Nb to within uncertainties, but its predictions are lower than the data by larger amounts as the target Z increases. Inclusion of an ad hoc semiclassical relativistic correction to the theoretical cross section, as suggested by Hansen, improves the agreement with the data, but overestimates the data for the highest-Z elements.

Description: This article discusses K-shell ionization of elements ₁₅P to ₂₈Ni for 0.4 to 3.8 MeV/amu ₅¹⁰B-ion bombardment. Abstract: K-shell x-ray production cross sections, Kβ/Kα x-ray intensity ratios and Kα and Kβ x-ray energy shifts have been determined for thin solid targets of ₁₅P, ₁₉K, ₂₀Ca, ₂₁Sc, ₂₂Ti, ₂₃V, ₂₅Mn, ₂₆Fe, ₂₇Co, and ₂₈Ni for 4-38-MeV ₅¹⁰B ion bombardment. Comparisons of the cross sections were made to direct Coulomb ionization and electron-capture theories by means of fluorescence yields corrected for multiple-ionization effects. The dominant contribution to K-vacancy production for these projectile-target combinations is believed to be direct ionization. Electron capture is expected to be important only for the lighter target elements and then primarily at the higher velocities. The direct-ionization theories employed were the binary-encounter approximation and the plane-wave Born approximation (PWBA) both of which overestimated the experimental data especially at the lower incident ion velocities. The PWBA was modified for increased target-electron binding, Coulomb deflection of the incident ion, polarization of the target-electron wave functions due to the passage of the incident ion, and relativistic target-electron velocities. The experimental data were found to agree quite well with the sum of the theoretical predictions of the modified PWBA and electron capture.