Nucleus-nucleus Reaction Cross Sections Research Articles

Effects of in-medium NN cross section and density distribution on the reaction cross sections of Ne, Mg, and O isotopes with C12 at 1 GeV

The nucleus-nucleus reaction cross sections of $^{18--34}\text{Ne},^{20--36}\text{Mg},^{16--24}\text{O}+^{12}\mathrm{C}$ at one GeV/u are calculated in the Glauber theory using different models of the nucleon-nucleon ($NN$) cross sections and nuclear densities. For in-medium effects, we consider the phenomenological (Ph), geometrical Pauli (GP), and modified combined (MC) models for the $NN$ reaction cross section. For the density distributions, we used the Sao Paulo (SP), Skyrme-Hartree-Fock (SHF), and the angle-averaged deformed Fermi (DF) densities. The results are compared with experiments as well as other theoretical calculations. It is found that the data can, generally, be described by using the Ph and GP models for in-medium effects with the SP density, which, on the other hand, predicted smaller radii. A satisfactory explanation of the experimental data is obtained by using more realistic densities such as SHF and DF with realistic radii, and the MC model for medium modifications, which involve the combined effect of the phase variation, higher momentum transfer components, and Pauli blocking of the $NN$ amplitude. The in-medium Ph and GP models when used with realistic densities, cannot describe the data at 1 GeV.

Measurement of He4 charge- and mass-changing cross sections on H, C, O, and Si targets in the energy range 70–220 MeV/u for radiation transport calculations in ion-beam therapy

Measured charge- and mass-changing cross sections for the systems $^{4}\mathrm{He}+^{12}C$, $^{4}\mathrm{He}+^{16}O$, $^{4}\mathrm{He}+^{28}\mathrm{Si}$, and $^{4}\mathrm{He}+^{1}\mathrm{H}$ in the energy range $70--220\phantom{\rule{4pt}{0ex}}\mathrm{MeV}/\mathrm{u}$ are presented. The cross sections were obtained via the attenuation method where a $\mathrm{\ensuremath{\Delta}}E\text{\ensuremath{-}}E$ scintillator telescope was used for particle identification. These new data have particular relevance for future applications of $^{4}\mathrm{He}$ ions in ion-beam radiotherapy because this technique relies on precise heavy ion transport models for an accurate dose calculation. The radiation transport codes applied for this purpose typically make use of parametrizations of the total reaction cross section ${\ensuremath{\sigma}}_{R}$. The widely used parametrization for nucleus-nucleus reaction cross sections by Tripathi et al. is shown to underpredict the new experimental cross sections for $^{4}\mathrm{He}$ ions in the therapeutic energy range by up to $30%$, which can lead to considerable dose calculation uncertainties. Therefore, modifications of the parameters in the Tripathi model are proposed to optimize it for applications related to $^{4}\mathrm{He}$ ion-beam therapy.

Probing the sensitivity of the total nucleus-nucleus reaction cross section at intermediate energies to medium effects and isospin asymmetries

This paper presents reaction cross-section predictions. These predictions are the result of a continuous pipeline that originates from a microscopic nuclear interaction. Density parameters and effective nucleon-nucleon cross sections (both involved in the reaction calculations) are by-products of the same equation of state. First, we perform tests of sensitivity to medium effects using reactions involving $^{208}\mathrm{Pb}$, a stable but weakly isospin-asymmetric nucleus. We also show predictions for collisions of some neutron-rich isotopes of calcium and argon. We observe significant sensitivity of the reaction cross section to medium effects but very weak sensitivity to inclusion of isospin asymmetry in the effective nucleon-nucleon cross sections.

Nucleus-nucleus reaction cross section at low energies: Modified Glauber model.

The Glauber model approach for the description of the heavy-ion reaction cross section is extended to lower energies. A simple analytic expression for the transparency function is obtained by evaluating the overlap integral of the nuclear densities over the hyperbolic trajectory. Using this transparency function the reaction cross section of a large number of heavy-ion systems is predicted reasonably well at low energies.

Low and intermediate energy nucleus-nucleus elastic scattering and the optical limit of Glauber theory

It is shown that a simplified Glauber approach using an experimental nucleon-nucleon forward amplitude and a Gaussian nucleus density reproduces fairly well both nucleus-nucleus reaction cross sections and elastic scattering differential cross sections over a broad energy range.

Nucleus-nucleus reaction cross sections at high energies: Soft-spheres model

A simple analytical expression is derived for the total nuclear reaction cross section in heavy-ion heavy-ion collisions at high energies based on the semiclassical optical model. Tapered nuclear density distributions are used in conjunction with nucleon-nucleon collision cross sections. NUCLEAR REACTIONS Nucleus-nucleus, high-energy; semiclassical calculation of total reaction cross sections, tapered density distributions.

Nucleus-nucleus reaction cross section at high energy collisions

The nucleon-nucleus and nucleus-nucleus reaction cross sections at high energies for various elements are calculated according to the optical model as a function ofσ0, the effective nucleon-nucleon total cross section in nuclear matter. Use is made of the charge distributions of various nuclei recently obtained from electron scattering experiments. The results are compared with existing data of experiments using machine beams and cosmic ray particles. But for the very light nuclei, a general agreement is found for values ofσ0 differing only by a few percent from the free nucleon-nucleon total cross section.