K-shell X-ray cross-section ratios for 1H, 4He and 6Li projectiles on targets from fluorine to titanium

Experimental K X-ray emission ratios have been measured for nine elements ranging from F to Ti (9 ? Z₂ ? 22) using ¹H⁺, and ⁶Li⁺ projectiles. The experimental ratios are in fair agreement with theoretical predictions for the velocity range studied, $\text{?}{}_{\mathrm{k}}\text{\$}\text{?}\text{1}$.     

Relativistic cross sections for atomic K- and L-shell ionization by protons,calculated from a Dirac-Hartree-Slater model

Relativistic direct ionization cross sections for proton impact have been computed for atomic K and L shells, with Dirac-Hartree-Slater wave functions. Corrections for binding, polarization, and Coulomb deflection are included. Results are tabulated for proton energies from about 0.1 to 3 MeV, for 27 elements with atomic numbers 22 ? Z ? 92.     

Experimental L-shell x-ray production and ionization cross sections for proton impact

Cross sections for L-shell x-ray production and ionization by protons are tabulated according to target atomic number, target type, and incident proton energy. Cross sections for production of the individual L-shell component x-rays and for ionization of the three L subshells are presented separately. Ratios of Lα to Ll x-ray production cross sections are also listed. Literature is covered from 1975 to November 1982. Experimental details pertaining to the cross-section measurements and the theoretical models employed by the experimenters for comparison with their data are included. It is intended that this information will help the reader to ascertain the most reliable cross-section values without recourse to the literature.     

Cross sections for K-shell ionization,x-ray production,or auger-electron production by ion impact

Cross sections for K x-ray production, K Auger-electron production, and K-shell ionization are tabulated as functions of target and projectile atomic numbers and projectile energy. The data are given in two tables. Table I presents data for the target-projectile systems where $\text{Z}{}_1\text{Z}{}_2\text{? 0.3}$. Table II presents data for published results where no restriction on the ratio $\text{Z}{}_1\text{Z}{}_2$ is applied and the studies were reported including data for different charge states of the incident heavy ion. Data are included in both tables for heavy ions incident upon gaseous targets, thick solid targets, and thin solid targets. However, data for solid targets ($\text{Z}{}_1\text{Z}{}_2\text{> 0.3}$) that have not taken into account the effects of target thickness on measured target x-ray yields are not included in the present tabulations. The literature from 1973 through 1977, has been covered. This work is thus a sequel to the 1973 compilation of Rutledge and Watson.     

K- and L-shell ionization cross sections for protons and helium ions calculated in the ecpssr theory

Ionization cross sections for K and L subshells are tabulated according to target atomic number and incident ion energy. Proton and helium ion energies between 100 keV and 10 MeV and selected targets between C and Am for the K shell and between Ar and Am for the L subshells are used. The cross sections have been calculated in the plane-wave Born approximation (PWBA) with corrections for energy loss (E), Coulomb deflection (C), perturbed stationary state (PSS), and relativistic (R) effects (ECPSSR).     

Tables for plane-wave Born-approximation calculations of K- and L-shell ionization by protons

Tables are presented in universal form for the calculation of plane-wave Born cross sections for proton-impact ionization of the K-shell and of individual L-subshells. The reason for these new calculations was twofold: First, these tables cover a wider range of proton energies and target binding energies than the original tables of Khandelwal et al., so that corrections for increased binding energy, Coulomb deflection etc. can be taken into account. Second, the table values have been calculated with the exact physical limits of integration given by energy and momentum conservation. This leads to lower cross-section values than in the original tables for low proton energies.     

Predictions of multiple K- and L-shell ionization by alpha-particle impact on atoms with Z = 10 to 100

The peaked binary-encounter approximation is used to compute cross sections for removing one or more electrons from K- and L-shells of atomic targets with Z = 10, 15, 20, 25, 30, 40, 60, 80 and 100 by bombardment with alpha particles. The cross sections, σ_{1K, nL} and σ_{2K, nL}, are plotted over a range of alpha energies in the MeV region near the peaks of these cross sections. The relative magnitudes of the σ_{1K, nL} and σ_{2K, nL} cross sections are similar. Estimates of multiple-ionization cross sections for other projectiles may be determined in some instances by means of the z² scaling law for the ionization probability.     

Prediction of (n,3He) cross-sections around 14 MeV

A comprehensive review of the neutron-induced cross-sections for (n,³He) reactions has been made for the interval of 14⩽Z⩽84 around 14 MeV neutron energy. For practical purposes, an empirical expression has been found by using the experimental (n,³ He) cross section values as a function of (N-Z) and (E_n-E_th) where (N-Z) is the neutron excess of the target nucleus, E_n and E_th are the incident neutron energy and the (n,³He) threshold energy, respectively. The derived empirical relation gives a good fit with the experimental values     

Recoil range of 2.7 MeV tritons produced by the 6Li(n, α) 3H reaction in Li2O single crystals

The tritium release from Li₂O single crystals due to a recoil process during neutron irradiation was investigated. The linear relationship between the number of tritium atoms ejected from Li₂O and the ⁶Li(n, α) ³H reaction density was observed up to about 1 × 10²⁴ reactions/m³ and the linearity was deviated above this reaction density. From this linear relationship, the recoil range of 2.7 MeV tritons in Li₂O single crystals was determined and discussed in terms of the calculated value.     

Stopping cross sections and backscattering factors for 4He ions in matter Z = 1–92, E(4He) = 400–4000 keV

A table is presented of semiempirical values of stopping cross sections [expressed in eV/(atom/cm²)] for ⁴He ions in every element (1 ≤ Z ≤ 92) for ion energies from 400 to 4000 keV. The semiempirical results have been fitted with polynomial expansions whose coefficients are also tabulated. The stopping cross sections provide parameters for the interpretation of backscattering experiments, for example factors for converting backscattering-peak widths to areal density (atoms/cm²). The semiempirical results are based on recent experimental measurements and on theoretical values calculated in the Lindhard-Winther formalism with Hartree-Fock-Slater elemental wavefunctions. Comments are included on combining the specific energy loss tables for compound backscattering analysis by using Bragg's Rule, and also on the effects on backscattering of target tilt and of the finite thicknesses of targets.     

An empirical expression for total scattering cross sections of normal hydrocarbons, and experimental total cross sections of C2H2 and C3H4

The total electron scattering cross sections (TCS) of C₂H₂ and C₃H₄ have been obtained for 200-4500 eV electrons by measuring the attenuation of the electron beam through a gas cell. An empirical expression is deduced to express the TCS of normal hydrocarbons as a function of the number of atomic constituencies in the hydrocarbon and the electron energy.     

Measured activation cross sections below 10 MeV for the 51V(n,p)51Ti and 51V(n, α)48Sc reactions

The activation method is used to measure cross sections for the ⁵¹V(n, p)⁵¹Ti reaction from E_n = 2.856 to 9.267 MeV and for the ⁵¹V(n, α)⁴⁸Sc reaction from 5.515 to 9.567 MeV. Both measurements utilize ENDF/B-V evaluated neutron-induced fission cross sections of ²³⁸U as a standard. The experimental results from this work are compared with corresponding ENDF/B-V evaluated cross sections for V and substantial differences are evident. The most significant difference is a tendency for the measured values to exceed evaluated ones by as much as 50% in the vicinity of 8 MeV.     

Direct non-dissociative and dissociative ionization of CO2 by positron impact

Detailed measurements of the cross-section for non-dissociative ionization of CO₂ are presented and compared with available experimental and theoretical results. An excellent agreement is found with the energy dependence of another experimental determination; however, uncertainties exist over the magnitude. Also presented are the preliminary results for the combined cross-section for direct dissociative ionization of CO₂ into O⁺ or C⁺.     

Cross section measurements of the 23Na(n, 2n)22Na, 58Ni(n, 2n)57Ni and 115In(n,n′)115mIn reactions

Cross sections for two high energy threshold reactions ²³Na(n, 2n)²²Na and ⁵⁸Ni(n, 2n)⁵⁷Ni were measured by the activation method in the neutron energy range from 14 to 18 MeV. Inelastic scattering cross section for ¹¹⁵In was measured in the threshold region, i.e. from 0.5 to 1.3 MeV. The results of measurements are compared with scarce and divergent earlier data.     

Electron impact ionization of N4+ and N5+

A new crossed beams apparatus for measuring absolute electron impact ionization cross-sections of multiply charged ions is described. First measurements are also reported which deal with N⁴⁺ and N⁵⁺. The results are in good agreements with those previously obtained by the Oak Ridge group. For N⁵⁺ a non-negligible signal is observed below the ground state ionization threshold. It is attributed to the presence of ions in metastable states. From the semi-empirical Lotz formula, the population of ions in those states is estimated to be approximately 3%.     

Studies of 1s2s 3S-1s2p 3P transitions in helium-like Ne8+ recoil ions using photographic spectroscopy

This work describes the application of the technique of photographic VUV spectroscopy to accurate measurement of the wavelength of the theoretically interesting 1s2s ³S₁-1s2p ³P₂ transition in helium-like Ne⁸⁺ in a recoil ion source. Good resolution is obtained, and a preliminary value of 124.815±0.002 nm is found for the wavelength.     

Na188ReO4、188Re-DTPA和188Re-MAG3的生物分布及排泄比较

为比较Na     

Depth resolution and recoil cross section for analyzing hydrogen in solids using elastic recoil detection with 4He beam

Two aspects of the elastic recoil detection technique for analyzing H and D are described; i) experimental factors which effectively limit the depth resolution in Al film, and ii) determination of the recoil cross section for H(⁴He, ⁴He)H and D(⁴He, ⁴He)D reactions in the range of 1.5–3.0 MeV energy of ⁴He. Both experimental and theoretical estimates of the depth resolution are presented and are in good agreement each other. The theoretical estimate therefore provides a reliable guide to find optimum resolution conditions. The recoil cross section for H is more than double the theoretical Rutherford scattering value and that for D becomes greater than 30 times Rutherford near the resonance energy of 2.1 MeV ⁴He.