[en] The L X-rays of ₇₁Lu, ₇₃Ta and ₇₉Au were produced by 1.5-4.5 MeV alpha particle bombardment. The emitted L_α, L_γ1 and L_γ2,3 lines were selected to convert X-ray production cross sections into ionisation cross sections. The ionisation cross sections obtained were compared with the predictions of the ECPSSR theory. A reasonable agreement of L₃-subshell ionisation cross sections between the present experiment and the ECPSSR theory is found. The departures of the measured L₂-subshell ionisation cross sections from the ECPSSR theory are discussed. (orig.)

[en] In the present work, vacancy enhanced krypton bubble formation in copper is studied with TEM. The vacancy concentration in excess of that produced by the energetic Kr atoms themselves has been introduced by implantation of Cu ions into Kr-preimplanted and subsequently annealed Cu specimens. TEM examinations reveal gradual increase of the fraction of Kr atoms gathered into bubbles, with increasing number of Cu²⁺ irradiation-annealing treatments, which eventually reaches 100%. A good correlation between the number of radiation vacancies and the number of vacancies contained by bubbles is found

[en] Multiple scattering and inelasticity effects in neutron scattering by a gaseous sample with an infinite plane slab geometry is studied as a function of the scattering angle for a perpendicular monochromatic incident beam. The importance of inelasticity effects in the treatment of the multiple scattering problem is shown. Monte Carlo simulations as well as approximate calculations are presented, and a correction procedure is proposed for the situation considered. (orig.)

[en] A Monte Carlo code has been developed to simulate individual electron interactions. The code has been instrumental in determining the range of validity for the widely used condensed history method. This task was accomplished by isolating and testing the condensed history assumptions. The results show that the condensed history method fails for low energy electron transport due to inaccuracies in energy loss and spatial positioning

[en] We study by molecular dynamics simulation the phenomena occurring in a condensed amorphous. Ar target induced by bombardment with a 1 keV Ar atom. We monitor the evolution of atom density and velocity in the target, the propagation of a shock wave in the initial phase, the distribution of kinetic and potential energy in the bombarded volume, and the energy spectrum of sputtered particles. We show that, among the 100 events studied, the most probable outcome is the formation of a huge cavity in the target of some 50 A diameter. In this case, the sputter yield Y is very small, Y < 30. If this cavity is situated close to the surface, the surface disrupts and hundreds of atoms are emitted into the vacuum above the target. The emission is driven by the high energy density and pressure building up in the core of the atom-induced collision cascade. Thermalization of the collision cascade and equilibration with its surroundings requires around 20 ps. Finally, we comment on the relationship of our results to existing models of condensed gas sputtering, and on the fluence dependence of sputter yields. (orig.)

[en] Experiments have been initiated which are designed to measure the time release characteristics of stable ion implanted species from selected refractory target materials which are potential candidates for forming radioactive beams at the proposed Oak Ridge Exotic Beam Facility (OREBF). The experiments are performed at the UNISOR facility by utilizing energetic HHIRF tandem accelerator ion beams to implant the species of interest into selected solid refractory target materials maintained at elevated temperatures within a FEBIAD-type ion source. In this report, we provide thermal time release data and estimates of efficiencies for releasing Cl from Zr₅Si₃ and ⁷⁵As, ⁷⁹Br, and ⁷⁸Se from Zr₅Ge₃. (orig.)

[en] We present an angle resolved study on the Auger electron emission from an Al surface under noble gas ion bombardment along the normal incidence direction for primary energies varying from 5-15 keV. We show that the intensity ratio between the atomic LMM and the bulk LVV features decreases according to an inverse cosine law as the detection goes from normal to grazing directions and that such ratio changes considerably with the primary ions (Ar⁺, Kr⁺ and Xe⁺). These results provide important information on the deexcitation mechanism of the core excited Al particles. (orig.)

[en] We propose a new method of depth profile determination using X-ray fluorescence analysis induced by synchrotron radiation. We show that uncertainties introduced in the solution of the system can be overcome using a calculation techniques based on a singular value decomposition of the matrix. This method may also apply to many other problems dealing with poorly conditioned systems. (orig.)

[en] High-fluence implantations of 100 keV N₂⁺ ion into a zirconium layer deposited by an electron beam were carried out at room temperature and at liquid-nitrogen temperature with and without nitrogen gas of a pressure of 1x10^-4 Torr. Depth profiles of atom concentrations were determined by Rutherford backscattering spectrometry, Auger electron spectroscopy, and resonance nuclear reaction analysis. The experimental results were compared with the theoretical results obtained by Monte Carlo simulations of the dynamic-SASAMAL code. The depth profiles measured by RBS agreed well with the calculated profiles for all fluences from 1x10¹⁷ to 5x10¹⁷ ions/cm², but differed from those obtained by AES indicating the existence of easily released nitrogen in the Zr specimen implanted with nitrogen at high fluence. Glancing angle X-ray diffraction was used to confirm zirconium nitride formation. (orig.)

[en] We study the preferential sputtering of the light isotope A_L over the heavy isotope A_H in a compound AB. We show by detailed balance arguments that the presence of species B has only a slight (5%) influence on the sputter preferentiality. A Monte Carlo computer simulation corroborates this result. (orig.)