Targeted Alpha Therapy (TAT) is considered the best method of treatment of malignant tissues. Alpha particles have interesting properties of destroying the cancerous cells due to their short penetration and high linear energy transfer. Hence, the use of alpha emitting radionuclides allows for targeting specific cancerous cells and killing of the individual cells while minimizing the toxicity to the surrounding healthy cells. The sources of the alpha for such application are the major concern. Investigation shows that Actinium-225 and Bismuth-213 are potential candidates for the production of alpha for TAT. Because of its short halve-life, the best method of production of Bismuth-213 is through 225 Ac/ 213 Bi generator hence the study of the production of Actinium-225. Critical literature review reveals that proton bombardment of thorium-232 is the best method of producing Actinuim-225. Therefore, the theoretical calculations of the production cross-sections were conducted using a nuclear modular code Empire. The calculated cross-sections were compared with one another and with the measured production cross-sections obtained from the experimental nuclear reaction data exchange format library contained in the nuclear data section of the International Atomic Energy Agency (IAEA), to investigate the effect of optical model’s configurations and the effect of the dispersive and relativistic optical model potentials on the production cross-section. The optical models’ configurations were designated by D1, D2 and D3 respectively for models that used to calculate coupled-channel transmission coefficients for the incident channel in addition to Distorted-Wave Born Approximation uncoupled, used for coupled-channel transmission coefficients for the incident and outgoing channel in addition to Distorted-Wave Born Approximation uncoupled, and used for Distorted-Wave Born Approximation calculation for all collective levels. The potentials are dispersive and relative potential, non-dispersive and relative potential, and the non-dispersive and non-relativistic potentials. The result obtained shows that the optical model configuration used to calculate coupled-channel transmission coefficients for the incident channel in addition to Distorted-Wave Born Approximation uncoupled produces the better effect on the production cross-section. Similarly, the model with Non-Dispesive and Non-Relativistic potentials produces netter yield while the optical model with Dispersive and Relativistic potential is more physically conservative. Hence any of the optical models can be used for the calculation of the production cross-section, regardless of the dispersive and relativistic potentials of the optical model.
The Interacting Boson Models, IBM1 and IBM2, analyzed in their O(6) limit are used to describe the properties of the 190 Hg isotope. A fitting procedure is used to determine the most accurate parameters to the calculated energy levels of this nucleus. The calculated ground, gamma, and beta bands energy of each model are compared to the previously measured data. Quadrupole electromagnetic transition strengths for 190 Hg, obtained from both IBM1 and IBM2, are presented and associated with previously experimental results. Finally, potential energy surfaces (PES) of 190 Hg in the dynamical symmetry O(6) of the IBM1 as an occupation of the restriction of the deformation are determined and discussed. All calculations are satisfied with experimental data.
This paper presents a multiple linear regression framework for reconstructing the historical helium-to-proton (He/p) flux ratio of galactic cosmic rays (GCRs) leveraging long-term, ground-based neutron monitor datasets. Optimized via a Stochastic Gradient Descent (SGD) algorithm, the model was calibrated and trained on direct satellite measurements from PAMELA and AMS-02 covering the period 2006–2019 and was subsequently applied to estimate the He/p ratio for the extended period of 1980–2019. The reconstruction results show good agreement when validated against independent historical data from balloon-borne e xperiments. Given that the He/p ratio is a crucial indicator of cosmic ray modulation, utilizing the extensive time coverage of the neutron monitor network provides deeper insights into solar modulation dynamics over past solar cycles.
The double-differential cross-sections (DDCS) and angular distributions for the neutron-induced reactions on the 107 Ag isotope were calculated at incident energies of 3, 5, 10, and 15 MeV within the pre-equilibrium region using the Kalbach model implemented in the PRECO-6 code and in conjunction with Feshbach-Kerman-Konnin statistical theory. Emitted nucleons’ total cross-sections were decomposed into direct (MSD) and compound (MSC) multistep components following Kalbach systematics expressed as d 2 σ/dΩ.dE . Results show that the d 2 σ/dΩ.dE a☺nd angular distribution for 107 Ag decrease systematically as the incident neutron energy increases, with markedly clearer structures for light ejectiles (neutrons and protons) than for heavy composite particles (deuterons, tritons, 3 He, and α particles). The latter also requires higher incident energies and exhibits spectral gaps under the present conditions. For two channels (n, n) and (n, p), calculations indicate that existing experimental data are not yet sufficient to firmly establish the energy dependence of the cross-sections, underscoring the need for precise measurements to constrain pre-equilibrium model parameters.
A numerical model for direct numerical simulation of compressible two-phase media is applied to the problem of gas-bubble rise in liquid lead. Because liquid metals are opaque and exhibit a very large density contrast between the gas and liquid phases, direct numerical simulation is an important tool for investigating interfacial dynamics and bubble-shape evolution. The paper presents 2D and 3D calculations performed with a two-phase flow code under development at IBRAE RAN using a previously developed surface-tension model integrated into the numerical algorithm. The numerical algorithm employs an explicit HLLC scheme with MUSCL reconstruction and equations of state to model compressible two-component media. The code is designed for the direct numerical simulation of thermal fluid dynamics in a two-phase compressible medium, including two-component mixtures, accounting for interfacial heat and mass transfer and using equations of state for Stiffened Gas or the Noble-Abel equation for weakly compressible media. The computed evolution of bubble shape and the time-dependent rise velocity are compared against experimental data for bubble rise in narrow rectangular channels. The simulated value of the rise velocity of a gas bubble with initial diameter of 3 mm agrees with the experimental average value of the rise velocity of moderate bubbles, entering the experimental channel through a nozzle of 3 mm in size, within 40%. This discrepancy is attributed to the insufficiently fine computational mesh used in the simulations.
