Extended tables for plane-wave Born-approximation calculations of direct Coulomb ionization of the K-shell by charged particles

Expressions used in the calculation of nonrelativistic K-shell cross sections for direct Coulomb ionization in the plane-wave Born approximation have been numerically integrated and tabulated for a range of projectile velocities and target binding-energy parameters which extends beyond that found in previous tables. The extended range of these parameters has been dictated by the need to apply subsequent developments in the basic theory to new heavy-ion data. The new table is intended to replace the others and is cast in terms of universal quantities. Analytical limiting forms are provided for use outside the region defined by the table.     

Nonperturbative effects in inner-shell ionization

A theoretical investigation of ion-induced inner-shell ionization is described, in which some physical effects that are nonperturbative in nature are included within the formalism of perturbation theory. In particular, the effects of the dynamical response of the outer electrons under the influence of the incident projectile are considered. Special emphasis is given to the use of nonorthogonal basis states in perturbation theory. Calculations for the proton- and ³He ion-induced total cross sections for K-shell ionization in titanium and copper are performed and compared with experimental data. Significant discrepancies between the theoretical results and the measured values are found to exist. Possible improvements to the theory are discussed.     

Efficiency of thermoluminescent detectors to heavy charged particles

The efficiency of TLD-700 thermoluminescent detectors is studied for various ions as a function of energy. A new model for calculation of efficiency has been developed, based on the detector response to reference radiation, and the radial dose distribution of heavy ions only. No free parameters have to be used to calculate the thermoluminescence detector (TLD) efficiency as a function of ion species and energy. Comparison between model calculations and experimental results will be presented.     

Density effect for the ionization loss of charged particles in various substances

The density-effect correction δ(β) for the ionization energy loss of charged particles has been evaluated as a function of the particle velocity for a total of 278 substances, including 98 cases of elements of the periodic table (12 gases and 86 condensed materials, including liquid hydrogen and graphite of three different densities) and 180 chemical compounds and substances of biological interest (13 gases and 167 liquid or solid substances). In the calculations, up-to-date values of the mean excitation potential I and of the atomic absorption edges hv_i were employed as input data for the general equations for δ(β) previously derived by Sternheimer.     

Alternative scattering power for Gaussian beam model of heavy charged particles

This study provides an accurate, efficient and simple multiple scattering formulation for heavy charged particles such as protons and heavier ions with a new form of scattering power that is a key quantity for beam transport in matter. The Highland formula for multiple scattering angle was modified to a scattering power formula to be used within the Fermi-Eyges theory in the presence of heterogeneity. An analytical formula for RMS end-point displacement in homogeneous matter was also derived for arbitrary ions. The formulation was examined in terms of RMS angles and displacements in comparison with other formulations and measurements. The results for protons, helium ions and carbon ions in water agreed with them at a level of 2% or the differences were discussed.     

The simulation of implantation of heavy charged particles in a crystalline material

We have studied the channeling effect in the ion implantation by simulating the collision of heavy charged particles with a crystalline material. In order to determine the penetration depth of fast heavy ions in crystalline material, we modified a model from pervious work and studied a situation where heavy As and P ions impinging on a crystal Si〈1 0 0〉 surface. A new stopping power calculation method is combined to the transport theory based ion range calculation equation for the fast and accurate numerical calculation of ion ranges. We simulated penetration event by dividing the surface of crystal in to three different region based on the distance from atomic centers in crystal structure. We solved differential equation numerically for each ions simulated. The results have been compared with similar models and the experimental data from literature. We found a good agreement with experiment for the behavior of distribution of ions in the crystalline substance. The model proposed here can be used successfully to predict channeling implantation profiles of heavy ions.     

Calculation of effect of a magnetic field on transport of fast heavy charged particles

Central Scientific Research Institute MO. Translated from Atomnaya Énergiya, Vol. 73, No. 6, pp. 493-495, December, 1992.     

Role of particle charge in impact ionization by charged microparticles

The role of particle charge in generating ionization of projectile and target in impacts of iron microparticles on copper has been investigated at impact velocities above 1 km s⁻¹. Charged microparticles are accelerated in an electrostatic accelerator and their surface charge subsequently reduced in flight by passage through a thin conducting film. It is found that a reduction in projectile charge of 80% at 5 km s⁻¹ reduces noticeably the degree of impact ionization. This supports the recent assertion that heating due to current flow between the particle and target immediately prior to impact may play a significant role in impact ionization at such velocities.     

Data evaluation of 169Yb-producing reactions by charged particles

Excitation functions for 169Yb production on low-medium energy accelerators, i.e. proton on 169Tm and natYb, deuteron on 169Tm, and 4He ion on natEr, were calculated by the ALICE/ASH and TALYS-1.0 codes. The target thickness was predicted by SRIM code. Theoretical integral yield for each reaction was compared with experimental data. The radionuclide purity of 169Yb from the 169Tm(p, n)169Yb reaction was determined, and maximum cross section predicted by the ALICE/ASH and TALYS-1.0 codes was about 182 and 154 mb at 11 and at 9 MeV, respectively.     

用CR－39固体径迹探测器测定重带电粒子的Bragg峰位

采用ＣＲ－３９固体径迹探测器，根据辐射损伤密度沿粒子的径迹分布规律，测定了经３、４ｃｍ空气降能和φ１ｍｍ孔准直的α粒子（５．１５ＭｅＶ）的Ｂｒａｇｇ峰位。对于通过３ｃｍ空气后能量降至～１２ＭｅＶ的α粒子，在ＣＲ－３９中的Ｂｒａｇｇ峰位大约在７μｍ深度处，理论计算值在６．１４μｍ，实验值与理论值符合得较好。     

Target-atom inner-shell vacancy distributions created in collisions with heavy ion projectiles

A model of the evolution of Cu atom inner-shell electron configurations was developed in order to establish the relationship between the original populations created in K-vacancy producing collisions with fast heavy-ion projectiles and those that exist at the time of Cu K and Kβ X-ray emission. The model takes into account multi-step vacancy rearrangement processes that may occur prior to K X-ray emission. An iterative procedure is employed in which a set of trial parameters that define the original inner-shell population distributions are varied to obtain satisfactory agreement of the calculated K satellite relative intensities and energies, as well as the overall intensity ratio of Kβ satellites to K satellites, with the experimental data. In addition to deducing the properties of the original L- and M-shell population distribution, this procedure also provides the average value of the fluorescence yield for conversion between X-ray and K-vacancy production cross sections.     

Metals analysis by charged particles: Evaluation and prospects

Charged particles are used to investigate objects from ancient metallurgy.Two methods are presented protonic and helionic activation analysis. These two methods; are compared with other methods this comparison takes into account the sensitivity, the precision, the metals alloys that can be analysed in a nondestructive manner, the thickness analysed, the representativity of the results and the archaeological problems they can solve.