Nuclear Reaction Cross Sections Research Articles

Measurements of the cross sections of nuclear reactions for the formations of 46,47,48Sc induced by neutrons around 14 MeV on titanium

The experimental cross sections of nuclear reactions for the formations of 46,47,48Sc on titanium (i.e. the cross sections of all the neutron nuclear reactions that directly produce the same daughter nuclei 46Sc, 47Sc and 48Sc on titanium, expressed as the cross sections of the Ti(n,x)46Sc, Ti(n,x)47Sc and Ti(n,x) 48Sc reactions, respectively) were measured in the neutron energies range of 13.5–14.8 MeV via the activation technique. The first experimental cross-section data for the formation of 48Sc on titanium were presented. The theoretical excitation curves of the above three reactions in the neutron energies from the threshold to 20 MeV were obtained by adopting TALYS-1.95 with the adjusted relevant parameters. The cross-section values measured for the Ti(n,x)46Sc, Ti(n,x)47Sc and Ti(n,x)48Sc reactions and their theoretical excitation curves are significant for the design of fusion reactor and the related applications.

Evaluation of Resonance Strengths and Reaction Rates of 22Ne (p, gamma) 23Na Nuclear Reaction at Thermonuclear Energies

At thermal energies near stellar conditions, nuclear reactions are sensitive to resonance strengths of the nuclear reaction cross-section. In this paper, the resonance strengths of nuclear reaction were evaluated numerically by means of nuclear reaction rate calculations using a written Matlab code, at the energies of interest in stellar nuclear reactions. The results were compared with standard reaction before and after application of statistical analyses, to select the best parameters that made theoretical results as close as possible to the standard values. Fitting was made for different temperature ranges up to 10 GK, 0.6 GK and 0.25 GK. The evaluated results showed that as the temperature range becomes narrower, more error is added to the evaluated strengths. A proper strength value based on the most recent measured one suggested the difference of at least one order of magnitude can be solved using a numerical evaluation for energies less than 650 keV.

Performance of machine learning algorithms on neutron activations for Germanium isotopes

In the studies of nuclear physics, one of the important parameters for nuclear reactions is the reaction cross-section. It can be obtained from experimental data or by different theoretical models. In this study, we implement machine learning (ML) algorithms to the regression analysis of the nuclear cross-section of neutron-induced nuclear reactions of Germanium isotopes. The data for the training of the machine was borrowed from the TENDL-2019 library for the total cross-section data of possible nuclear reactions after the bombardment of the different target materials by neutrons. Three ML models, Artificial Neural Networks (ANN), K-Nearest Neighbors (KNN) and, Support Vector Machines (SVM), were developed to fit nuclear data from the TENDL-2019 database in order to predict neutron induce reaction cross sections. The performance of each algorithm is determined and compared by evaluating the mean square error (MSE) and the correlation coefficient (R2). According to the results obtained, we demonstrate that cross-section information can be obtained safely with ML techniques and the regression curve generated by our models is in good agreement with the evaluated nuclear data library. From our study, ANN and KNN are found to be better compared to SVM algorithm. ML models can enhance classical physics-guided models and play a role in nuclear data analyses. They can be used as an alternative to the estimation of cross-sections for neutron energies of an unknown energy value.

Measurement of 9Be(3He,p i )11B (i = 0, 1, ..., 9) nuclear reaction cross sections in the 1.0 MeV to 2.5 MeV energy range

In fusion materials research using ion beam analysis techniques, the reactions 9Be(3He,p i )11B (i = 0, 1, 2…) are relevant to probe Be-related plasma-wall interactions. The cross sections for this reaction have been examined previously; nevertheless, there is a ∼40% difference in the studied energy interval between the two most relevant earlier studies. Therefore, a new data set for the differential cross sections 9Be(3He,p i )11B for the proton groups i = 0, 1, …, 9 is given. The measurements were performed using a thin beryllium film in the laboratory energy range from 1.0 MeV to 2.5 MeV in steps of 50 keV for lab angles from 115° to 165° to the incoming beam direction in steps of 10°. Additional measurements for intermediate angles were performed over the same energy range in steps of 250 keV. The results are in good agreement with one of the previous studies and a benchmarking measurement was performed against the yield of a beryllium thick target at 2.5 MeV for 135°.

Deuteron and α-particle-induced nuclear reactions on 45Sc: activation cross section measurement and thick target yield evaluation

Systematic measurements of nuclear reaction cross sections were done in the low energy range for the two reactions 45Sc(d,p)46Sc and 45Sc(α,n)48V. Thin foils of high-purity (99.95%) natural Sc targets (100% 45Sc), purchased from Good-Fellow, were irradiated with 10 and 20 MeV incident deuteron and α-particle energies, respectively, at beam current of 100 nA using MGC-20 cyclotron. For precise measurements, high-purity Ti and Cu foils were used for monitoring the actual deuteron and α-particle beam intensities, respectively. The conventional stacked-foil technique was applied for measurement and calculation of the cross section values using a high-resolution γ-ray spectrometer for measuring the radioactivity. Nuclear model code EMPIRE-3.2 was used for calculation of the investigated excitation functions. The obtained results were compared with the experimental values and TENDEL-2021 data which are based on TALYS-1.96 code calculations. The integrated yields for the two reactions, based on the proposed average excitation functions, were estimated.

Investigation of the Cross-Sections for the Production of Bromine Isotopes Using Proton-Induced Reactions

We have considered the production of bromine isotopes by studying the cross-sections of nuclear reactions in the selenium enriched target. This is of importance due to the applications in nuclear medicine and radiation therapy. Eight channels are observed in the production of bromine isotopes: 7634Se(p, 2n) 7535Br, 7734Se(p, 3n) 7535Br, 7634Se(p, n) 7635Br, 7734Se(p, 2n) 7635Br, 7734Se(p, n) 7735Br, 7834Se(p, 2n) 7735Br, 8034Se(p, 4n) 7735Br, and 8034Se(p, n) 8035mBr. The energy of the interacting protons ranging from the threshold is 2.20–84.20 MeV and is calculated by using an activation technique. For the proton-induced production of bromine isotopes from selenium target atoms, the stopping power and the yield have been calculated. The Zeigler formula was applied to investigate the cross-sections and to determine the yield for each reaction over the stopping power range. The total energy of each reaction and the corresponding crosssections are statistically analyzed. These energies are reproduced by the incident proton energy with acceptable errors at 0.01 MeV intervals. One of the most significant results of the current calculations is the stopping power of targets evaluated within the Ziegler and SRIM approaches.

Resonance self-shielded multigroup atomic displacement cross section for assessing neutron irradiation damage

Accurate calculation of neutron-induced displacement damage is a key step for the subsequent investigations on neutron irradiation damage. Due to the use of multigroup displacement damage cross sections, the resonance self-shielding effect of neutron-induced nuclear reaction must be taken into account. In addition to the method proposed by the authors in 2019, two additional methods are proposed in the present work to consider the self-shielding effect on the calculation of neutron irradiation-induced displacement damage. The two newly proposed methods allow directly using self-shielded multigroup nuclear reaction cross sections without infinite-dilution cross sections, even though they are not as consistent as the first one in the case of weak resonance self-shielding effect. The resulting resonance self-shielding corrections on the displacement damage of 56Fe in a typical sodium-cooled fast reactor are quite close for the three different methods. The slight differences (within ∼ 2 %) are much smaller than the self-shielding corrections, which are about −11.3 % for the dominant neutron elastic scattering-induced damage and −10.4 % for the total displacement damage.

Measurement and calculation of isomeric cross section ratios for the natW(3He, x)184m,gRe reactions

Excitation functions for the natW(3He, x)184m,gRe nuclear reactions were measured from respective thresholds up to 55 MeV by using a conventional stacked-foil activation technique combined with HPGe γ-ray spectroscopy. Individual cross-section values for the production of 184mRe and 184gRe were separated using a proper mathematical method based on their interference-free characteristic gamma lines and the data are reported here for the first time. The default parameters of recently developed nuclear model code TALYS-1.96 were found to be unable to reproduce the excitation functions, hence cannot provide 184mRe/184gRe isomeric cross-section ratios consistent with the experimental results. However, the adjustment of the level density model and optical model potentials together with some other parameters, such as the spin cut-off parameter, were found to be effective to reproduce the measured excitation functions. A similar parameter adjustment may be useful to reproduce the excitation functions of like unusual isomeric pairs, especially when the metastable state is longer-lived than the ground state.The reported cross-sections and the model calculation show interesting in the understanding of the nuclear reaction mechanisms as well as for the improvement of nuclear model codes for accurate prediction of nuclear reaction cross-sections where the experimental data are scarce, or an expensive experiment is required to obtain experimental data.

A new targetry system for production of zirconium-89 radioisotope with Cyclone-30 cyclotron

Abstract In this study, an efficient method for targetry and production of zirconium-89 radioisotope (89Zr) with Cyclone-30 cyclotron was developed. The preparation of a highly pure compressed yttrium oxide target material and design of a target made by copper for better heat transfer was performed. Electrodeposition of target with gold was done to prevent the entry of metallic impurities (copper, zinc and other trace metal elements). Nuclear reaction cross sections for optimization of production with new target and irradiation parameters of the target were evaluated. The prepared 89Zr in the form of [89Zr] Zr-oxalate had high radionuclidic purity (>99.9%) and a low chemical impurity concentration (<0.1 ppm for copper and zinc elements). The yield of 89Zr radioisotope production via the reaction of 89Y(p,n)89Zr was measured to be 77 ± 9.5 MBq/μAh (time of irradiation = 3, the current 20–30 µA). [89Zr] Zr-oxalate specific-activity was in the range 2.319641 × 104–3.479443 × 104 MBq/mmol of Oxalate.

Nuclear Astrophysics at the Low-Energy Frontiers: Updates from underground laboratories

Nuclear fusion reactions are the heart of nuclear astrophysics: they sensitively influence the nucleosynthesis of the elements in the earliest stages of the Universe and in all the objects formed thereafter; control the associated energy generation and neutrino luminosity; influence the evolution of stars. Unfortunately, measuring reaction cross sections at astrophysically relevant energies is exceptionally challenging due to Coulomb repulsion between nuclei, resulting in cross section values as low as fbar. Laboratorial measurements of these cross sections are often unfeasible due to overwhelming cosmic-ray-induced backgrounds. One effective solution to this problem is to conduct experiments in underground laboratories. The Laboratory for Underground Nuclear Astrophysics (LUNA) is an experimental approach based on an underground accelerator focusing on studying nuclear fusion reactions. Its primary objective is to accomplish direct measurement of cross sections for nuclear reactions that have significance in stellar and primordial nucleosynthesis. This article will present the latest findings and future objectives.

A novel R-matrix formalism for three-body channels

At low incident neutron energies nuclear reaction cross sections exhibit a distinct resonance structure which cannot properly be described by (semi-)microscopic models. Usually R-matrix theory is applied which provides a suffi ciently accurate but phenomenological description of the resonance region. However, standard R-matrix theory is only suited for two-particle channels. Three- and many-particle channels which may occur in light nuclear systems even at rather low incident energies are usually treated in an approximative or effective way. In this contribution a novel R-matrix formalism for three-body channels and its application to nuclear systems will be presented. It is a generalized and significantly modified form of a proposal by W. Glöckle based on the Faddeev equations.

18FDG Production in a PET Imaging Using a Proton Flux Produced by the D-D Fusion Reaction

Fluorine 18-deoxyglucose (18FDG) is often used in Positron Emission Tomography (PET). PET imaging is one of the valuable tools used for cancer detection and management. PET growth is limited due to problems that depend on the production of Fluorine-18. Imaging results are strongly dependent on the information of nuclear reaction cross-section data. This study calculates the stopping power, RCSDA, and the simulated and distributed absorbed dose of F-18, in water. We use the Geant4/Gate simulation and the Bethe-Bloch theory model to access these goals. The results of this simulation and this theory model agree with each other. The main point of this paper is the presentation of a theoretical approach to the production of Fluorine-18 by using protons production through the main nuclear fusion reaction D(d,p)T and the side fusion reaction 3 He(d,p)4 He uses helium-3 as a catalyzed.

14.77 MeV neutron-induced nuclear reaction cross sections for zinc, yttrium, and molybdenum targets* *S. D. Dhole and V. N. Bhoraskar gratefully acknowledge the financial assistance given by SERB-DST, New Delhi sanction number: EMR/2017/002497 for research in the field of neutron-induced nuclear reactions.

The cross sections for neutron-induced nuclear reactions on natural zinc, yttrium, and molybdenum targets were measured at a neutron energy of 14.77 ± 0.17 MeV using the activation technique, offline gamma-ray spectrometry, and a detailed covariance analysis. The uncertainty in the statistical model calculations of cross sections for the (n, 2n), (n, p), (n, α), and (n, γ) reactions with natural zinc, yttrium, and molybdenum at neutron energies from 13 to 17 MeV was calculated using the TALYS-1.96 nuclear code. The measured cross sections of the present study were compared with the experimental cross sections reported in the EXFOR database, the cross sections were calculated with the TALYS-1.96 and EMPIRE-3.2.3 nuclear codes and the evaluated nuclear data from the TENDL-2019, JENDL-5, and ENDF/B-VIII.0 libraries.

Research of spallation reaction on plutonium target irradiated by protons with energy of 660 MeV

Relevance. This paper describes the measurement of the cross sections of the fission and fragmentation reactions of a plutonium target irradiated with a series of protons characterized by an energy of 660 MeV at the Phazotron accelerator of the Joint Institute for Nuclear Research. Purpose. The experiment focuses on the determination of short-lived radionuclides. Methods. The experimental sample was measured in offline mode using gamma spectrometry with HPGe detector. The reaction rates of the formed residual nuclei were studied. The products of spallation reaction were determined with the help of the direct kinematics method. The DEIMOS32 software was used to process γ-spectra. Results. As a result of the interaction of nuclear elements with protons, nuclei were formed in the 239Pu sample. Those nuclei were identified using the TJ02000321–V3 software. The reaction products were identified based on gamma energies, intensity and half-life after the measurement set. During the study of the gamma spectra determined for the irradiated plutonium target, it was possible to establish 50 gamma lines and reveal 31 nuclides by energy and half-life cycles from 14.4 m to 3.19 h. The measured nuclear reaction cross-sections can serve as reference data for theoretical simulations of the interaction of protons with 239Pu and they can be a supplement to the nuclear databases. Conclusions. The obtained experimental result is compared with the simulation on MCNP 6.1. The data overall correspond to the expected range, but it still needs more evaluation. The next logical step is to search for primary products (mother nuclei) and compare the obtained experimental data with the results of computer simulations

Evaluation of Empirical Equations of Asymmetry Parameter for Magic Nuclei in Z forn,  Reaction of Incident Neutron Energy 14.5 MeV

In this study, the magic nuclei are divided into two groups: the middle group and the heavy group. The shell corrections were calculated for all nuclei. The relationship between cross sections for nuclear reactions n,  and the mass number (A) for all nuclei to incident neutrons (14.5 MeV) were calculated. We found empirical equations to asymmetry parameter (N-Z)/A as function of massnumber and for those two groups.

Alternative routes for 64Cu production using an 18 MeV medical cyclotron in view of theranostic applications

Radiometals play a fundamental role in the development of personalized nuclear medicine. In particular, copper radioisotopes are attracting increasing interest since they offer a varying range of decay modes and half-lives and can be used for imaging (60Cu, 61Cu, 62Cu and 64Cu) and targeted radionuclide therapy (64Cu and 67Cu), providing two of the most promising true theranostic pairs, namely 61Cu/67Cu and 64Cu/67Cu. Currently, the most widely used in clinical applications is 64Cu, which has a unique decay scheme featuring β+-, β−-decay and electron capture. These characteristics allow its exploitation in both diagnostic and therapeutic fields. However, although 64Cu has extensively been investigated in academic research and preclinical settings, it is still scarcely used in routine clinical practice due to its insufficient availability at an affordable price. In fact, the most commonly used production method involves proton irradiation of enriched 64Ni, which has a very low isotopic abundance and is therefore extremely expensive. In this paper, we report on the study of two alternative production routes, namely the 65Cu(p,pn)64Cu and 67Zn(p, α)64Cu reactions, which enable low and high 64Cu specific activities, respectively. To optimize the 64Cu production, while minimizing the mass of copper used as a target in the first case, or the co-production of other copper radioisotopes in the second case, an accurate knowledge of the production cross sections is of paramount importance. For this reason, the involved nuclear reaction cross sections were measured at the Bern medical cyclotron laboratory by irradiating enriched 65CuO and enriched 67ZnO targets. On the basis of the obtained results, the production yield and purity were calculated to assess the optimal irradiation conditions. Several production tests were performed to confirm these findings.

Accelerator Mass Spectrometry, an ultrasensitive tool to measure cross sections for stellar nucleosynthesis

The combination of the activation method and accelerator mass spectrometry (AMS) has grown to be an important resource to measure nuclear reaction cross sections, especially when these are very small. The activation method refers to the production of long-lived radioisotopes by nuclear reactions induced by charged particles, neutrons, or γ-rays. The ultrasensitivity achieved by AMS allows the detection of even a very small number of such long-lived radioactive products. Several reviews of this topic have been published recently and our goal in this work is to continue with the review effort by including some of our own publications, as well as a few more.

An improved theoretical method for determining the mean D-T neutron energies in large solid angle sample

ABSTRACT Neutron energy of deuterium-tritium (D-T) generator plays an important role for the application of nuclear energy and nuclear technology. Based on the deuterium energy losing in tritiated titanium (T-Ti) target and differential cross sections of D-T reaction, an improved theoretical formula for calculating the mean neutron energy irradiating a large solid angle sample was proposed. Besides that, the mean neutron energy was discussed under the actual experimental conditions. The results were compared to the reported ratio values of 90Zr(n,2 n)89m+gZr to 93Nb(n,2 n)92mNb reaction cross sections (‘Zr/Nb’ ratio methods) and published theoretical calculated results, respectively. The relative deviations between present work and the ‘Zr/Nb’ ratio methods are below 0.5% and a higher precision was obtained compared with previous published theoretical method. The present work lays a foundation for the application of D-T neutron source in nuclear technology such as nuclear reaction cross section measurement, calibration of neutron detector, and neutron irradiation tests, etc.

Analysis of cross-section, S-factor and thermonuclear reaction rate of 8Li(α,n)11B and 14N(p,γ)15O using TALYS and EMPIRE nuclear reaction codes

Theoretical nuclear reaction codes are crucial for studying cross-section and S-factors of nuclear reactions required for the thermonuclear reaction rate calculations. We analyze two reactions 8Li([Formula: see text])11B and 14N([Formula: see text])15O, using both TALYS and EMPIRE codes. We stress that these reactions are highly important for CNO cycle but the extent of involvement of experimental datasets are meager and conflicting. For the first reaction, the trend of experimental data has been predicted satisfactorily by the codes. The reaction rate is also matched with REACLIB calculation. However, in 14N([Formula: see text])15O, none of the codes could predict the resonant structures in the experimental data at the lower energies. The importance of our work is a sincere attempt to validate the TALYS and EMPIRE predictions for cross-section, S-factor and the reaction rate, simultaneously.

EVALUATION OF 67Ga CROSS SECTIONS USING EXIFON CODE FOR MEDICAL APPLICATIONS

Radioisotopes play very important roles in nuclear medicine for imaging and therapeutic applications. In the present studies, model calculation of excitation function for production of 67Ga radioisotope was performed using the EXIFON code, a nuclear reaction cross sections theoretical model code, for the reaction 65Cu(α, 2n)67Ga. The work was performed in the incident alpha energy range of 0 - 40 MeV. Similarly, the Q-value software (interface) was used for the calculation of reaction threshold and Q-value energies of the reaction of interest and were respectively found to be 14.97 MeV and -14.10 MeV. The calculated excitation function has a peak value of 1025 mb around 25 MeV incident energy. The results from the EXIFON code were compared with the experimentally measured cross sections data retrieved from IAEA database, the EXFOR database, as well as the theoretical data from Talys code via its library, the TENDL-2019. Our results partially agree with the theoretical data from Talys code (via the TENDL-2019 library) within the investigated energy region. The results however overestimated the measured (experimental) data and only agree in shape of the excitation function. The present work does not consider the effect of shell structure during the execution of the EXIFON model code. This work could be of importance to the developers and users of nuclear reaction model codes for new developments and enhancements of the existing codes, as well as to serve as a rough guide for experimentalists during production of radioisotopes for nuclear medicine applications