Alpha-induced Reaction Research Articles

Production of 97Ru and 103Ru radionuclide from alpha-induced reaction on natMo

Production of 97Ru and 103Ru radionuclide from alpha-induced reaction on natMo

Measurement of alpha-induced reaction cross-sections for [formula omitted]Zn with detailed covariance analysis

The production cross-section of 68Ge, 69Ge, 65Zn and 67Ga radioisotopes from alpha-induced nuclear reaction with natZn have been measured using the stacked foil activation technique followed by the off-line γ-ray spectroscopy in the incident alpha energy range 14-37 MeV. The obtained nuclear reaction cross-sections are compared with previous experimental data available in the EXFOR data library, evaluated nuclear data from TENDL-2019 and theoretical results, calculated using TALYS nuclear reaction code. We have also performed the detailed uncertainty analysis for these nuclear reactions and their respective correlation metrics are presented. Since α-induced reactions are important in nuclear medicine and developing the nuclear reaction codes so needful corrections related to the coincidence summing factor and the geometric factor have been considered during the data analysis in the present study.

Measurement of excitation functions for nat Cu(α, x) reactions with detailed covariance analysis

The excitation functions of 66Ga, 67Ga, 65Zn and 64Cu radioisotopes produced via alpha-induced reaction on nat Cu were measured using a stacked foil activation method. The gamma-ray activity produced by the above mentioned radionuclides was measured using the HPGe detector. The covariance analysis was performed to quantify the measured cross-section uncertainties as well as the correlation between different alpha energy cross-sections. A covariance matrix and cross-sections for the nat Cu(α, x)66Ga, nat Cu(α, x)67Ga, nat Cu(α, x)65Zn and nat Cu(α, x)64Cu nuclear reactions in the projectile energy range of 15–37 MeV are reported in the present work. The measured reaction cross-sections are compared with the existing experimental data and theoretically simulated results from the TALYS code.

Measurement of alpha-induced reaction cross-sections on $$^{nat}$$Mo with detailed covariance analysis

In the present study we have measured the excitation functions for the nuclear reactions $^{100}$Mo($\alpha$,n)$^{103}$Ru, $^{nat}$Mo($\alpha$,x)$^{97}$Ru, $^{nat}$Mo($\alpha$,x)$^{95}$Ru, $^{nat}$Mo($\alpha$,x)$^{96g}$Tc, $^{nat}$Mo($\alpha$,x)$^{95g}$Tc and $^{nat}$Mo($\alpha$,x)$^{94g}$Tc in the energy range 11-32 MeV. We have used the stacked foil activation technique followed by off-line gamma ray spectroscopy technique to measure the excitation functions. In this study we have also documented detailed uncertainty analysis for these nuclear reactions and their corresponding covariance matrix are also presented. The excitation functions are compared with the available experimental data from EXFOR data library and the theoretical prediction from TALYS nuclear reaction code. The present measurements are found to be consistent with the available experimental data.

Medical radiaosotopes production: Activation cross-sections of 52Mn by the alpha-induced reaction on natural vanadium (V)

Excitation functions for α-induced reactions on natural vanadium were calculated in the energy range up to 50 MeV. The production cross sections of 52Mn will be compared to some previously published results and the TALYS (TENDL 2019) code calculations. The integral yield of 52Mn is derived from the calculated cross-sections and compared with those from other production routes.

Sensitivity Study of Type-I X-ray Bursts to Nuclear Reaction Rates

Type-I X-ray bursts are frequently occurring thermonuclear runaways on the surface of an accreting neutron star. The different nuclear reactions that empower the cataclysmic event play a key role in accurately comparing theoretical models and observations. We investigate the effect of the uncertainties in the nuclear reactions using a ONEZONE model for a set of different compositions and accretion rates that are within the range of the standard observed burst sources. A combination of a full-reaction network and a semi-analytic model is used to obtain the conditions at the time of X-ray burst ignition via simulating the settling process of the accreted material. We then evaluate the sensitivity of the X-ray burst model by varying the proton and alpha-induced reaction rates in JINA REACLIBV2.2 within representative nuclear physics uncertainties.

Production of energetic 232U, 236,238Pu, 242Cm, 248Bk, 250,252Cf and 252Es radioisotopes for use as nuclear battery in thin targets via particle accelerators

Energetic 232U, 236,238Pu, 242Cm, 248Bk, 250,252Cf and 252Es nuclei used in nuclear batteries were produced by using particle accelerators for proton, deuteron, triton, helium-3 and alpha-induced reaction processes on thin targets. The energy range used was Eparticle = 100 → 1 MeV, including specific conditions such as irradiation time of 24 h with constant beam current of 1 μA. The impressive results were obtained in terms of charged-induced reaction processes, based on simulated activity and yield of product curves. In addition, the significance of these results was discussed for each reaction process so as to determine the appropriate reaction process in detail and add nuclear data to the literature. Also, obtaining these radioisotopes has loud economic cost and restrictions of target materials. Therefore, target materials in production processes were carried out in thin targets to provide convenience to experimenters.

Role of consistent parameter sets in an assessment of the α -particle optical potential below the Coulomb barrier

Background: Further studies of high-precision measurements of alpha-induced reaction data below the Coulomb barrier have still raised questions about the alpha-particle optical model potential (OMP) within various mass ranges, i.e. for 64Zn, 108Cd, 113,115In, 121,123Sb, and 191,193Ir target nuclei. Purpose: The accuracy as well as eventual uncertainties and/or systematic errors of using a previous optical potential are much better considered by analysis of such accurate data. Method: Statistical model (SM) calculations of the (alpha,x) reaction cross sections have been carried out using model parameters which were previously obtained by analyzing independent data, particularly gamma-ray strength functions, and taking into account their uncertainties and questions of extrapolation for nuclei without similar data. Results: Consistent description of the recent alpha-induced reaction data is provided by the above-mentioned optical potential with no empirical rescaling factors of either its own parameters or the gamma and/or nucleon widths. Effects of still uncertain SM parameters on calculated alpha-induced reaction cross sections and conclusions on the alpha-OMP can be now discussed due to unprecedented precision of the new data. Conclusions: The alpha-particle optical potential has been confirmed at incident energies below the Coulomb barrier using statistical-model parameters validated through a former analysis of independent data.

α -induced reactions on In115 : Cross section measurements and statistical model analysis

[Background] Alpha-nucleus optical potentials are basic ingredients of statistical model calculations used in nucleosynthesis simulations. While the nucleon+nucleus optical potential is fairly well known, for the alpha+nucleus optical potential several different parameter sets exist and large deviations, reaching sometimes even an order of magnitude, are found between the cross section predictions calculated using different parameter sets. [Purpose] A measurement of the radiative alpha-capture and the alpha-induced reaction cross sections on the nucleus 115In at low energies allows a stringent test of statistical model predictions. Since experimental data is scarce in this mass region, this measurement can be an important input to test the global applicability of alpha+nucleus optical model potentials and further ingredients of the statistical model. [Methods] The reaction cross sections were measured by means of the activation method. The produced activities were determined by off-line detection of the gamma-rays and characteristic x-rays emitted during the electron capture decay of the produced Sb isotopes. The 115In(alpha,gamma)119Sb and 115In(alpha,n)118Sbm reaction cross sections were measured between Ec.m. = 8.83 MeV - 15.58 MeV, and the 115In(alpha,n)118Sbg reaction was studied between Ec.m. = 11.10 MeV - 15.58 MeV. The theoretical analysis was performed within the statistical model.

Alpha-induced reaction cross-section for Sm, U, Np targets: influence of hexadecapole deformation and deformed surface diffuseness

Alpha-induced reactions on 154Sm, 233,235,236,238U, and 237Np deformed nuclei are studied theoretically. The effects of hexadecapole deformation, deformed surface diffuseness parameter, and orientation on barrier height and position, fusion cross-section at any angle, and fusion cross-section have been investigated. Both hexadecapole deformation and deformed surface diffuseness can affect barrier characteristics and enhance fusion cross-section. Good agreement between experimental data and theoretical calculations with quadrupole and hexadecapole deformation and deformed surface diffuseness were observed for the 4He+154Sm, 235U, 237Np reactions.

α scattering and α -induced reaction cross sections of Zn64 at low energies

Background: alpha-nucleus potentials play an essential role for the calculation of alpha-induced reaction cross sections at low energies in the statistical model... Purpose: The present work studies the total reaction cross section sigma_reac of alpha-induced reactions at low energies which can be determined from the elastic scattering angular distribution or from the sum over the cross sections of all open non-elastic channels. Method: Elastic and inelastic 64Zn(a,a)64Zn angular distributions were measured at two energies around the Coulomb barrier at 12.1 MeV and 16.1 MeV. Reaction cross sections of the (a,g), (a,n), and (a,p) reactions were measured at the same energies using the activation technique. The contributions of missing non-elastic channels were estimated from statistical model calculations. Results: The total reaction cross sections from elastic scattering and from the sum of the cross sections over all open non-elastic channels agree well within the uncertainties. This finding confirms the consistency of the experimental data. At the higher energy of 16.1 MeV, the predicted significant contribution of compound-inelastic scattering to the total reaction cross section is confirmed experimentally. As a by-product it is found that most recent global alpha-nucleus potentials are able to describe the reaction cross sections for 64Zn around the Coulomb barrier. Conclusions: Total reaction cross sections of alpha-induced reactions can be well determined from elastic scattering angular distributions. The present study proves experimentally that the total cross section from elastic scattering is identical to the sum of non-elastic reaction cross sections. Thus, the statistical model can reliably be used to distribute the total reaction cross section among the different open channels.

Analysis of uncertainties inα-particle optical-potential assessment below the Coulomb barrier

Background: Recent high-precision measurements of alpha-induced reaction data below the Coulomb barrier have pointed out questions of the alpha-particle optical-model potential (OMP) which are yet open within various mass ranges. Purpose: The applicability of a previous optical potential and eventual uncertainties and/or systematic errors of the OMP assessment at low energies can be further considered on this basis. Method: Nuclear model parameters based on the analysis of recent independent data, particularly gamma-ray strength functions, have been involved within statistical model calculation of the (alpha,x) reaction cross sections. Results: The above-mentioned potential provides a consistent description of the recent alpha-induced reaction data with no empirical rescaling factors of the and/or nucleon widths. Conclusions: A suitable assessment of alpha-particle optical potential below the Coulomb barrier should involve the statistical-model parameters beyond this potential on the basis of a former analysis of independent data.

Relation between total cross sections from elastic scattering andα-induced reactions: The example of64Zn

The total reaction cross section is related to the elastic scattering angular distribution by a basic quantum-mechanical relation. We present new experimental data for alpha-induced reaction cross sections on 64Zn which allow for the first time the experimental verification of this simple relation at low energies by comparison of the new experimental reaction data to the result obtained from 64Zn(alpha,alpha)64Zn elastic scattering.

Alpha-induced reaction cross section measurements on 151Eu for the astrophysical γ-process

In order to extend the experimental database relevant for the astrophysical γ-process towards the unexplored heavier mass region, the cross sections of the 151Eu(α, γ)155Tb and 151Eu(α, n)154Tb reactions have been measured at low energies between 12 and 17 MeV using the activation technique. The results are compared with the predictions of statistical model calculations and it is found that the calculations overestimate the cross sections by about a factor of 2. A sensitivity analysis shows that this discrepancy is caused by the inadequate description of the α+nucleus channel. A factor of 2 reduction of the reaction rate of 151Eu(α, γ)155Tb in γ-process network calculations with respect to theoretical rates using the optical potential by McFadden and Satchler (1966 Nucl. Phys. 84 177) is recommended.

Compilation and Evaluation of Alpha-Induced Nuclear Reaction Cross Sections For Astrophysics

Nucleosynthesis and energy production in stellar environments depend critically on nuclear reaction cross sections. Reactions induced by alpha particles are important in the helium burning stage of stars, novae, and supernovae events. They involve light to medium weight nuclei up to about Z=32, and center-of-mass energies up to about 20 MeV. We are working on a project to compile and evaluate cross section data for alpha-induced reactions. These data will eventually be used to derive α-nucleus potential parameters.

Angular-Momentum Effects in theMg24(α,Be7)andAl27(p,Be7)Reactions at 35-65 MeV

The reaction ${\mathrm{Mg}}^{24}(\ensuremath{\alpha},{\mathrm{Be}}^{7}){\mathrm{Ne}}^{21}$ is investigated with alpha particles in the energy range 35-63 MeV. The measured cross sections are compared with the cross sections for ${\mathrm{Al}}^{27}(p,{\mathrm{Be}}^{7}){\mathrm{Ne}}^{21}$, a reaction which proceeds through the same compound nucleus, ${\mathrm{Si}}^{28}$. At fixed excitation energy of the compound nucleus (C.N.), the alpha-induced reaction has a higher cross section for ${E}_{\mathrm{C}.\mathrm{N}.}>40$ MeV. The cross-section ratio $\frac{\ensuremath{\sigma}(\ensuremath{\alpha})}{\ensuremath{\sigma}(p)}$ increases from 4.4\ifmmode\pm\else\textpm\fi{}1.0 at ${E}_{\mathrm{C}.\mathrm{N}.}=50$ MeV to 6.3\ifmmode\pm\else\textpm\fi{}1.4 at ${E}_{\mathrm{C}.\mathrm{N}.}=60$ MeV. Part of this significant difference is shown to be due to angular-momentum effects in compound-nuclear processes. The balance is attributed to the multinucleon pickup by the He ion. A similar effect is observed in the reactions ${\mathrm{Al}}^{27}(p,\ensuremath{\alpha}pn)$ and ${\mathrm{Mg}}^{24}(\ensuremath{\alpha},\ensuremath{\alpha}pn)$.

Proton Resonances in the Deuteron Bombardment of Carbon

The protons resulting from the deuteron bombardment of ${\mathrm{C}}^{12}$ have been studied in some detail, with particular emphasis on the variation of the intensity of the long-range protons with energy and angle. Excitation curves at three fixed angles, one forward, one backward, and one at 90\ifmmode^\circ\else\textdegree\fi{} to the beam, show peaks which in some cases agree in energy with one another and with neutron and gamma-peaks observed in the same bombardment elsewhere. In other cases, however, there is no peak on one mode of observation at an energy where one appears in another. In some cases peaks in different modes of observation which do not quite coincide in energy are so close together that it seems reasonable to attribute them to the same virtual level of the compound nucleus, and the existence of the small energy discrepancies is discussed. Two shorter range groups of protons are studied less extensively because they penetrate the thin windows only at high bombarding energies, and their range coincides with that of the scattered deuterons at some bombarding energies. The two short range groups indicate excited states of ${\mathrm{C}}^{13}$ at 3.12 and 3.91 Mev. A possible low excited state near 0.8 Mev, suspected from an alpha-induced reaction, is not confirmed. The transition to it cannot be shown to be absent but only weak because protons indicating its existence could be masked by protons observed from an oxygen impurity. Of the three angular distributions observed in detail, the one at the lowest bombarding energy is the simplest, in keeping with the expectation that only deuterons of low angular momentum penetrate at low energies.