K. Kawatsura

X-ray emission from boron and boron nitride by bombardment with nitrogen and argon ions

Abstract The X-rays of the boron atom emitted from thick boron and boron nitride targets by bombardment with nitrogen (0.3–1.1 MeV) and argon (0.3–1.8 MeV) ions are investigated. The spectra from the boron target consist of two peaks due to single and double K-shell vacancies. For boron nitride, the spectra due to single and double K-shell vacancies have two and one satellites, respectively. The intensity ratio of the high energy side satellites of both spectra to each main peak increases with the decrease of the incident energy of the projectiles in the energy range examined. This fact suggests that the high energy satellites are due to the transition from the 2p level of the nitrogen atom to the 1s level of the boron atom with a 2p vacancy. Moreover, absolute cross sections have been measured for the single and double K-shell ionizatione of the boron atom by heavy ion bombardment. The energy dependence of the ionization cross sections suggests that the mechanism of the inner shell ionization is understood by the electron promotion model during the collisions.

Channelling of H+ and He+ ions in pyrolytic graphite

Abstract Much research has been devoted to the understanding of the channeling of high-energy ions in crystals. This communication presents a preliminary experimental result on the ion chnnelling along the c−axis ([0001] axis] of pyrolytic graphite by the use of wide-angle Rutherford scattering.

Beryllium double K X-ray emission by proton and helium ion bombardment

Abstract X-ray spectra from beryllium by proton and helium ion bombardment are studied. A clear peak due to double K-shell ionization is observed at 146.1 eV by helium ion bombardment. For proton bombardment, a peak of double K-shell ionization is not observable.

Multiple inner-shell ionization in oxygen produced by ion bombardment in the MeV range

Abstract Oxygen X-ray spectra from oxide targets by proton, helium, nitrogen and argon ion bombardment are studied. K satellite and hypersatellite peaks are observed. In light ion bombardment, X-ray production of the double K-shell ionization indicated large deviation from the Z 2 1 dependence.

Radiation effect study of single-crystal austenitic stainless steel by ion channeling spectroscopy

Abstract The radiation effect on the lattice structure of single-crystal austemtic stainless steel SUS310S under He ion bombardment was studied. The He+ ions, with an energy of 1.7 MeV, were incident along the 〈100〉, 〈110〉 or 〈111〉 axes of the specimen. constituent elements induced by He ions as well as Rutherford-backscattered He ions were measured. The lattice location of the alloying and impurity atoms, and their disordering caused by the He irradiation were investigated. It was shown that aligned X-ray yields in the angular scans increase with the irradiation dose except for P atoms, and the degree of the increase depends very much on the crystallographic orientation and the constituent elements. Some of the impurity P atoms were found to be situated at the body-centered site of the fcc crystal and to be displaced from this site under He ion irradiation.

Molecular effect of Al K α X-ray yields from aluminum oxide films for H+ and H+2 ion bombardments

Abstract Al Kα X-ray spectra for equi-velocity H + and H + 2 ions of ≃ 0.9 MeV/amu incident on thin aluminum oxide films with thickness 100 and 300 A were observed. The intensity ratio of the KL 1 satellite line to the KL 0 main one for H + 2 incident on the films of thickness 100 and 300 A was about 10% and 4% larger than that for incident H + , respectively.

He+ ion energy loss parameter in thin films of UO2

Abstract The stopping cross sections of He + ions in vacuum evaporated films of UO 2 have been measured at incident energies from 0.3 to 2.0 MeV. A procedure has been described for obtaining true stopping cross sections by using thin films having various thicknesses. The energy loss parameter of He + ions was determined using slopes at the origin in relative energy loss vs. thickness curves.

Projectile Z dependence of double K-shell ionization in light elements by hydrogen- and helium-ion bombardment

Abstract The K 2 X-rays from Be, B and O atoms by H- and He-ion bombardment were measured. The ratio of σ 2K (He) to σ 2K (H) exhibits the projectile Z 4 1 dependence. This is the first observation of the Z 1 -dependence of σ 2K predicted by the Coulomb excitation.

Single and double K-shell ionization cross sections of fluorine by light ion bombardments

Abstract The K α satellite and hypersatellite X-ray spectra have been measured for fluorine produced by 0.3–2.0 MeV H and He ion bombardments of the thick LiF target. The single and double K-shell ionization cross sections derived from the X-ray yields have been compared with theoretical calculations based on the binary-encounter approximation (BEA) and the semiclassical Coulomb approximation (SCA). The result shows that the observed cross sections for the single K-shell ionization agree with the BEA better than with the SCA and those for the double K-shell ionization systematically differ from the BEA by a factor of three.

Energy and lifetime measurements in highly ionized chlorine

Abstract Charge states and angular distributions of 150 MeV Cl ions have been measured as a function of carbon target thickness (2.5–180 μg/cm 2 ). Evidence for the large shell effect under single collision conditions is found in the thinnest target. Transition energies in highly ionized Cl ions have been measured using a grazing incidence monochromator at the VUV region, and using a crystal spectrometer and a Doppler-tuned spectrometer at the X-ray region. The lifetimes have also been measured using the time of flight technique at the VUV and X-ray regions. Results of measurements are given and some are discussed in comparison with other data.