Energy Distribution Of Emitted Particles Research Articles

Dark fluxes from electromagnetic cascades

We study dark sector production in electromagnetic (EM) cascades. This problem requires accurate simulations of Standard Model (SM) and dark sector processes, both of which impact angular and energy distributions of emitted particles that ultimately determine flux predictions in a downstream detector. We describe the minimal set of QED processes which must be included to faithfully reproduce a SM cascade, and identify a universal algorithm to generate a dark sector flux given a Monte-Carlo simulation of a SM shower. We provide a new tool, , which simulates EM cascades with associated dark vector production, and compare it against existing literature and “off the shelf” tools. The signal predictions at downstream detectors can strongly depend on the nontrivial interplay (and modelling) of SM and dark sector processes, in particular multiple Coulomb scattering and positron annihilation. We comment on potential impacts of these effects for realistic experimental setups.

CR-39 track detector calibration with H and He beams for applications in the p-11B fusion reaction

The 11B(p,α)2α reaction, generating three alpha particles, emerges as a promising alternative or complementary route for clean and efficient energy generation. A comprehensive understanding of reaction dynamics, energy distribution of emitted particles, and optimization of fusion efficiency requires precise diagnostic methods. CR39 detectors, being highly sensitive to ions and neutrons while remaining transparent to low fluxes of electrons and gammas, are extensively utilized as primary Solid State Nuclear Track Detector devices in laser-plasma environments. This study presents the CR-39 track detector calibration to low-energy protons and alpha particles. CR-39 irradiation took place at INFN-LNL (Istituto Nazionale di Fisica Nucleare — Laboratori Nazionali di Legnaro, Legnaro, Italy) across a range of energies (≥ 80 keV) up to a few MeV, employing various etching times with a NaOH solution. The observed discrepancy in particle diameters, related to a specific etching time, presents a promising avenue for distinguishing alpha particles from proton contributions. This finding holds potential for future practical applications in the study of 11B(p,α)2α fusion reactions.

Sensitivity of secondary particle emission to hadronic physics models in GATE/Geant4 proton therapy simulations at 100 MeV

Introduction: Proton therapy simulations rely on Monte Carlo techniques, such as the GATE code based on the Geant4 toolkit, to predict dose distribution and secondary particle production. The accuracy of these simulations is heavily influenced by the chosen physics models. Methods: In this study, we analyzed three Geant4 hadronic physics models, BIC, BERT, and INCL++, by calculating the angular and energy distributions of secondary neutrons and gamma particles. We conducted GATE/Geant4 simulations on a water phantom irradiated with a 100 MeV proton beam. Results: Our investigation revealed notable differences in the angular and energy distributions of emitted particles among the three models. Conclusion: This study emphasizes the necessity of carefully selecting a hadronic physics model for GATE/Geant4 simulations in proton therapy.

Calculation of Neutron Nuclear Data on Rubidium and Strontium Isotopes for JENDL-4

Neutron nuclear data on 85,86,87Rb and 84,86,87,88,89,90Sr have been calculated for the evaluated nuclear data library JENDL-4 in the energy region from 10 keV to 20MeV. Simultaneously calculated are the total, elastic, and inelastic scattering, (n,γ), (n, p), (n, d), (n, t), (n,3He), (n,α), (n, np), (n, nd), (n, nα), (n, 2n), (n, 3n) reaction cross sections, angular distributions of emitted particles, and energy distributions of emitted particles and γ-rays. The statistical model was applied to calculate these quantities. Coupledchannel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present calculations are consistent with available experimental data. The calculated results are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Selenium Isotopes for JENDL-4

Neutron nuclear data on 74,76,77,78,79,80,82Se have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, (n, γ), (n, p), (n, d), (n, t), (n, 3He), (n, α), (n, np), (n, nd), (n, nα), (n, 2n), (n, 3n) reaction cross sections, angular distributions of emitted particles, and energy distributions of emitted particles and γ-rays. The statistical model was applied to calculate these quantities. Coupled-channel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present calculations are consistent with available experimental data. The calculated results are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Rubidium and Strontium Isotopes for JENDL-4

Neutron nuclear data on 85,86,87Rb and 84,86,87,88,89,90Sr have been calculated for the evaluated nuclear data library JENDL-4 in the energy region from 10 keV to 20MeV. Simultaneously calculated are the total, elastic, and inelastic scattering, (n,γ), (n, p), (n, d), (n, t), (n,3He), (n,α), (n, np), (n, nd), (n, nα), (n, 2n), (n, 3n) reaction cross sections, angular distributions of emitted particles, and energy distributions of emitted particles and γ-rays. The statistical model was applied to calculate these quantities. Coupledchannel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present calculations are consistent with available experimental data. The calculated results are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Molybdenum Isotopes for JENDL-4

Neutron nuclear data on 92,94,95,96,97,98,99,100 Mo have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, (n, p), (n, d), (n, t), (n, 3He), (n, α), (n, np), (n, nd), (n; nα), (n, 2n), (n, 3n) reaction cross sections, the angular distributions of emitted particles, and the energy distributions of emitted particles and γrays. The statistical model was applied to calculate these quantities. Coupled-channel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present calculations are almost consistent with available experimental data. The calculated results are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Molybdenum Isotopes for JENDL-4

Neutron nuclear data on 92,94,95,96,97,98,99,100 Mo have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, (n, p), (n, d), (n, t), (n, 3He), (n, α), (n, np), (n, nd), (n; nα), (n, 2n), (n, 3n) reaction cross sections, the angular distributions of emitted particles, and the energy distributions of emitted particles and γrays. The statistical model was applied to calculate these quantities. Coupled-channel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present calculations are almost consistent with available experimental data. The calculated results are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Silicon Isotopes for JENDL-4

Neutron nuclear data on 28,29,30Si have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, and (n, p), (n, α), (n, γ), (n, 2n), (n, 3n), (n, np), and (n, nα) reaction cross sections, the angular distributions of emitted neutrons, and the energy distributions of emitted particles and γa-rays. The statistical model was applied to calculate these quantities. Coupled-channel optical model parameters were obtained so as to reproduce measured cross sections. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. It is confirmed that the present calculations are almost consistent with available experimental data. The calculated data are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Silicon Isotopes for JENDL-4

Neutron nuclear data on 28,29,30Si have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, and (n, p), (n, α), (n, γ), (n, 2n), (n, 3n), (n, np), and (n, nα) reaction cross sections, the angular distributions of emitted neutrons, and the energy distributions of emitted particles and γa-rays. The statistical model was applied to calculate these quantities. Coupled-channel optical model parameters were obtained so as to reproduce measured cross sections. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. It is confirmed that the present calculations are almost consistent with available experimental data. The calculated data are compiled into JENDL-4.

Calculation of Neutron Nuclear Data on Calcium Isotopes for JENDL-4

Neutron nuclear data on 40,42,43,44,46,48Ca have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, (n, p), (n, α), (n, γ), (n, 2n), (n, 3n), (n, np) and (n, nα) reaction cross sections, the angular distributions of emitted neutrons, and the energy distributions of emitted particles and γ-rays. The statistical model was applied to calculate these quantities. Pre-equilibrium and direct-reaction processes were taken into account in addition to the compound process. It is found that the present calculations are almost consistent with available experimental data and much better than the JENDL-3.3 evaluation. In particular, the measured γ-ray production data are well reproduced by the present calculations.

Calculation of Neutron Nuclear Data on Calcium Isotopes for JENDL-4

Neutron nuclear data on 40,42,43,44,46,48Ca have been calculated for the evaluated nuclear data library JENDL-4. Simultaneously calculated are the total, elastic and inelastic scattering, (n, p), (n, α), (n, γ), (n, 2n), (n, 3n), (n, np) and (n, nα) reaction cross sections, the angular distributions of emitted neutrons, and the energy distributions of emitted particles and γ-rays. The statistical model was applied to calculate these quantities. Pre-equilibrium and direct-reaction processes were taken into account in addition to the compound process. It is found that the present calculations are almost consistent with available experimental data and much better than the JENDL-3.3 evaluation. In particular, the measured γ-ray production data are well reproduced by the present calculations.

Pair versus many-body potentials in atomic emission processes from a Cu surface

Atom emission from the (100) surface of a Cu crystal is investigated using molecular dynamics simulation. Different potentials are employed: the Morse potential as an example of pair potentials, and many-body potentials of the EAM and the tight-binding type. Many-body potentials lead to a slightly smaller surface binding energy than pair potentials, when fitted to the same cohesive energy of the bulk crystal. Furthermore, many-body potentials lead to a stronger refraction of emitted atoms away from the surface normal. As a consequence, the maximum in the energy distribution of emitted particles is shifted to around 50% higher energies for many-body potentials, if compared to the prediction of the model of a planar surface barrier. These characteristic deviations between pair and many-body potentials are explained by using simple analytical reasoning.

Calculation of Neutron-Induced Reaction Cross Sections of Manganese-55

Neutron-induced reaction cross sections of 55Mn are calculated for the evaluated nuclear data libraries, ENDF/B-VI and JENDL-3. Simultaneously calculated are the inelastic scattering, (n,2n), (n,p), (n,α), (n,np), (n,nα) and (n,γ) reaction cross sections, the angular distributions of emitted neutrons and protons, and the energy distributions of emitted particles and γ-rays. A unified Hauser-Feshbach code is applied to calculate these quantities. Precompound and direct-reaction processes are taken into consideration, in addition to the compound process. The calculated results reproduce the experimental data very well. Forward-peaked angular distributions of continuous neutrons are obtained from the calculation, and found to be consistent with the measurements at 14MeV.

Calculation of neutron-induced reaction cross sections of Manganese-55.

Neutron-induced reaction cross sections of 55Mn are calculated for the evaluated nuclear data libraries, ENDF/B-VI and JENDL-3. Simultaneously calculated are the inelastic scattering, (n,2n), (n,p), (n,α), (n,np), (n,nα) and (n,γ) reaction cross sections, the angular distributions of emitted neutrons and protons, and the energy distributions of emitted particles and γ-rays. A unified Hauser-Feshbach code is applied to calculate these quantities. Precompound and direct-reaction processes are taken into consideration, in addition to the compound process. The calculated results reproduce the experimental data very well. Forward-peaked angular distributions of continuous neutrons are obtained from the calculation, and found to be consistent with the measurements at 14MeV.

Angular momentum effects on the decay of compound nuclei

Data are presented on the energy distribution of emitted particles from the Rh 103(α,α′), Rh 103(α,p) and Mo 92(α,p) reactions. Data from these and other experiments for particles expected to arise from compound nucleus formation and decay have been subjected to analysis via the compound-statistical model for nuclear reactions. The calculations take into account the angular momentum distribution of the compound and residual nuclei. The apparent variation of level density parameter with changing bombarding energy observed in the results of previous analyses of similar data continue to be observed in the present results.

Method to Obtain the Energy Dependence of Reaction Cross Sections When a Compound Nucleus is Formed

It is found that measuring the energy distributions of emitted particles at two different incident energies and two reaction cross sections is sufficient to obtain the energy dependence of a reaction cross section when it is known that a compound nucleus is formed. The cross sections obtained are a function of the excitation energy of the residual nucleus. They are the usual reaction cross sections at zero excitation energy when the assumption is made that the reaction cross section does not vary with the excitation energy of the target nucleus. By comparing the reaction cross sections thus obtained with measured nonelastic cross sections, the compound elastic cross section may also be obtained. An example using this method is given in which two measured energy distributions and two measured cross sections were used to obtain the energy dependence of the reaction cross section of nickel in the 2.5- to 7-Mev energy range.

Disintegration of Light Nuclei by -Meson Capture

o-stars in photographic plates are classified into those originated from heavy and light nuclei. The branching ratio of disintegration modes, the a-j ratio, and the energy distribution of emitted particles are measured for light stars. Foilowing characteristic features of light stars are ascertained; 1) the large prong number, 2) the large a-p ratio, 3) the low kinetic energy of emitted particles, and 4) the frequent emission of heavy fragments. The disintegration of 0 2 into two a-particles and a proton are studied in detail, and the possible emission of BeB nuclei is discussed. It turns out to be the main disintegration mode, that the rcst energy of o-meson is primarily shared among only a few member of nucleons and the residual part ramains in a similar to the excited levels appeared in low energy reactions.

Disintegration of Light Nuclei by σ-Meson Capture

σ-stars in photographic plates are classified into those originated from heavy and light nuclei. The branching ratio of disintegration modes, the a-p ratio, and the energy distribution of emitted particles are measured for light stars. Following characteristic features of light stars are ascertained; 1) the large prong number, 2) the large a-p ratio, 3) the low kinetic energy of emitted particles, and 4) the frequent emission of heavy fragments. The disintegration of C12 into two a-particles and a proton are studied in detail, and the possible emission of Be8 nuclei is discussed. It turns out to be the main disintegration mode, that the rest energy of σ-meson is primarily shared among only a few member of nucleons and the residual part remains in a similar to the excited levels appeared in low energy reactions.