Nuclear Model Code Research Articles

Neutron-induced reaction cross section measurements for palladium isotopes at 14.77 ± 0.17 MeV with covariance analysis

The nuclear reaction cross sections for 110Pd(n,2n)109mPd, 102Pd(n,2n)101Pd, 106Pd(n,p)106mRh, 110Pd(n,2n)109gPd and 105Pd(n,p)105Rh have been measured at the neutron energy of 14.77 ± 0.17 MeV by using the method of activation and off-line γ-ray spectrometry. The uncertainties in the various nuclear parameters in the measured reactions and their correlations were estimated by using covariance analysis. The present data were compared with literature data from the EXFOR database and nuclear data libraries, including ENDF/B-VIII.0, JEFF-3.3, JENDL-5.0 and TENDL-2021. Theoretical model calculations for the cross-sections are performed with the TALYS-1.96 nuclear model code with optimized parameters. There is good agreement between the measured, literature and evaluated data. The results are important for shielding applications in the radiation fields involving neutrons.

Evaluation of the cyclotron production of the positron emitters 43Sc, 44gSc and beta emitter 47Sc radionuclides: An emerging theranostic pair

The theranostic pair of Scandium radionuclides: 43/44Sc positron emitters along with 47Sc beta emitter, has been gaining attention in the field of nuclear medicine over the last decades. The charged particle induced reactions, namely 43Ca(p,n)43Sc, 44Ca(p,n)44Sc, 44Ca(p,2n)43Sc, 46Ti(p,α)43Sc, 48Ca(p,2n)47Sc, 41K(α,2n)43Sc,40Ca(α,p)43Sc, 41K(α,n)44gSc and 44Ca(α,p)47Sc were evaluated for the high purity production of the 43Sc, 44gSc and 47Sc radionulicdes. Three Nuclear model codes (TALYS 1.9, ALICE-IPPE and EMPIRE 3.2) were used to check the consistency and reliability of the experimental excitation functions. A comprehensive evaluation methodology was used to generate the recommended cross sections, for each production route and their corresponding radioisotopic impurities. The final recommended cross sections are at last based on the statistical fitting of the resulting combination of both experimental data and theoretical nuclear model calculations. Thick target yields were calculated by using the recommended/reference cross sections. After a careful analysis and comparison of the evaluated production routes, namely 43Ca(p,n)43Sc, 44Ca(p,n)44gSc and 48Ca(p,2n)47Sc are suggested for the high purity cyclotron production of the 43Sc, 44gSc and 47Sc radionuclide respectively.

Computation of Cross-sections by Effects of Theoretical Parameters Code for Production of 52Mn Radioisotope

Abstract: Theoretical calculations focusing on cross-section data results for the production of 52Mn from a natural chromium (natCr) target have been investigated for deuteron beams up to 35 MeV by using the EMPIRE 3.2.2 Malta nuclear model code. The optimization of theoretical calculations is important for the medical production routes of cross-section isotopes. In these computations, we tested different ATILNO parameters for the evaluation of cross-section data and improved techniques for the theoretical calculation of radioisotope 52Mn. The effects of these parameters were investigated, and the theoretical results were subsequently compared with each other, existing literature data, and the TENDL-2019 library. Keywords: EMPIRE code, Cross-section, Manganese-52, Radionuclide production, Positron emission tomography.

Fast neutron induced reaction cross sections on natural manganese and tantalum

The cross sections for the 55Mn(n,2n)54Mn, 181Ta(n,2n)180gTa, and 181Ta(n,p)181Hf reactions were measured to be 705.1 ± 26.1 mb at 14.0 MeV, 1362.7 ± 87.2 mb at 13.6 MeV, and 2.31 ± 0.09 mb at 13.6 MeV, respectively, by using an off-line γ-ray spectroscopic technique. The neutrons were produced via the 3H(d,n)4He reaction. The monitor reactions 27Al(n,α)24Na and 93Nb(n,2n)92mNb were used for neutron flux determination. The results from the present work were compared with those of the literature and the evaluated data from ENDF/B-VIII.0, JEFF-3.3, JENDL-5, CENDL-3.2, and BROND-3.1 libraries. Besides, the cross sections were also estimated with the TALYS-1.96 nuclear model code using different level density models for a better description of the present work and literature data. The present experimental results were found to be in good agreement with most of the available literature data and with the evaluated data.

Evaluation of the cross section data for the low and medium energy cyclotron production of 77Br radionuclide

77Br (T1/2 = 57 h) is an important auger electron emitter used in internal radiotherapy. For the cyclotron production of 77Br, the charged particle induced reactions namely 75As(α,2n)77Br, 77Se(p,n)77Br, 78Se(p,2n)77Br, and 80Se(p,4n)77Br were critically evaluated. Literature experimental data were normalized according to the modern standard of the decay data and monitor reactions. Three nuclear model codes (EMPIRE 3.2, TALYS 1.9, and ALICE-IPPE) were used to check the consistency and reliability of the experimental data. For each production route and corresponding radioisotopic impurity (76Br), a well-developed evaluation methodology was employed to generate the statistically fitted recommended excitation function. The recommended excitation functions were then employed to calculate the integral yield. After a comparative analysis on the basis of product yield, level of radioisotopic impurities; the reactions namely 77Se(p,n)77Br and 78Se(p,2n)77Br were suggested for high purity production of 77Br radionuclide using low and medium energy cyclotron respectively.

Yield of residues produced in 6Li reaction on Ta: A comparative analysis for 183Os

The present work reports an analysis of the production yield of residues from the 6Li ＋ 181Ta reaction in a low-energy regime. The experimental yield of 183gOs, 183mOs, 182Os, 183Re, 183Ta, 182m2Ta, and 180Ta have been measured in the 27–43 MeV energy window and compared with equilibrium and pre-equilibrium model calculations under the framework of the nuclear reaction model code, EMPIRE-3.2.2. The maximum yield measured for 183gOs is 80.5 ± 14.9 MBq/C at 40.2 MeV energy in a 2.3 mg/cm2 thick Ta target corresponding to a cross-section of 360.1 ± 34.4 mb from the 181Ta(6Li,4n)183Os reaction and that for 183Re is 1.36 ± 0.4 MBq/C at 42.75 MeV in a 2.4 mg/cm2 thick target. The model estimations agree well with the experimental yields of 183gOs and 183Re. The possible production of stable residues has been estimated using the model-predicted cross-section in the studied energy range. A comparison of production yields of 183m,gOs from 6Li- and 7Li-induced reaction on Ta demonstrates the 6Li reaction as a better candidate. Thick target yields have been evaluated for Os and Re isotopes.

Structural material nuclear data basic research

The nuclear data evaluation for deuteron-induced reactions andα-particle emission by neutron interactions is addressed within “Nuclear data for fusion technology, from basic research to full-scale applications.” The status and open questions related to these subjects in the area of nuclear data for fusion technology, specifically for the nuclear design of the ITER fusion device, the European DEMO fusion reactor, and the IFMIF-DONES Irradiation Facility, are briefly reviewed. A firm demand for accurate cross-sections of reactions induced by neutrons and deuterons exists, in this respect, within a more enlarged energy range up to 50 MeV than for fission applications. The current requirements are closely met by the TENDL Evaluated Nuclear Data Library, settled using the TALYS nuclear model code, which is one of the most widely used codes in basic research and applications including nuclear fusion technology. However, further improvement of this data library has recently been suggested, while, with respect to fission applications, not only the aforementioned energy range but also the diversity of nuclear data for fusion technologies is plainly stretched. Consequently, the progress of nuclear data activities conducted more recently on deuteron-induced reactions andα-emission by neutron interactions, throughout the European Fusion Program and subsequent to previous achievements within F4E and EUROfusion programs, is wholly summarized.

Activation cross sections of proton-induced reactions on manganese up to 30 MeV

The excitation functions of the 55Mn(p,x)51Cr, 54Mn reactions were measured up to 30-MeV proton energy. The experiment was performed at the RIKEN AVF cyclotron using the stacked-foil activation technique. High-purity germanium (HPGe) detectors were used for the gamma-ray spectrometry. Obtained results were compared with previous experimental data and the prediction of the TALYS nuclear reaction model code available in the TENDL-2021 library. Physical thick target yields of 51Cr and 54Mn were derived from the measured cross sections.

Systematic study of (p, n) and (p, 2n) reactions on 110Cd

Standard activation analysis technique with γ ray spectroscopy via off-line mode was utilized for reaction cross section estimation. The proton beam was transported from the BARC-TIFR accelerator and targeted on the natCd target. The 16 MeV proton beam irradiated the sample, and Copper foil was utilized as an energy degrader. The activation cross sections were estimated for 110Cd(p, n) reaction for the ground state (Jπ = 7+) population of 110In nucleus and 110Cd(p, 2n)109In reaction at 14.14 MeV of proton energy. Along with experimental measurements, the theoretical study has been carried out for ground and metastable states population by utilizing the nuclear model code TALYS-1.95, EMPIRE-3.2.3, and ALICE-2014 for both reaction channels. The estimated cross sections are valuable for the improvement of theoretical nuclear model codes for a comprehensive knowledge of nuclear reaction mechanisms. The produced isotopes 109,110In have significant importance in Positron Emission Tomography (PET) studies. The present study is a dive into the phenomenological and microscopic level density models of different nuclear model codes in predicting excitation functions.

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.

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.

Cross-section measurements of the 81Br(n,2n)80mBr reaction via secondary nuclear decay

The secondary nuclear decay method was applied for the cross-section measurement of the 81Br(n,2n)80mBr reaction. As a result, the cross-sections of the 81Br(n,2n)80m,gBr reactions with a detailed uncertainty propagation and their isomeric cross-section ratios σm/σg were obtained at four neutron energies within the range from 13 to 15 MeV by applying an activation and off-line γ-ray spectrometric technique. The Br-based samples and Nb-based monitor foils were activated together to determine both the reaction cross-sections and the incident neutron flux. The neutron beam was formed via the 3H(d,n)4He reaction. The cross-sections were also calculated by using a theoretical nuclear model code TALYS-1.95 with different options of level density at neutron energies varying from the reaction threshold to 20 MeV. The extracted results were analytically discussed and compared with the corresponding theoretical and evaluated data from the published works in the literature.

A Problem in the Statistical Description of Beta-Delayed Neutron Emission

Reaction measurements on fission products are being planned at both Argonne National Lab and at the Facility for Rare Isotope Beams. These indirect experiments produce specific short-lived nuclei via beta decay, and the subsequent neutron and gamma emission are studied. Some initial experiments found a surprising overabundance of gamma emission, which theory has yet to explain. To remedy this, we are developing an integrated nuclear data workflow that connects advanced nuclear shell model codes for describing the beta decay with a contemporary nuclear reaction model code.

Measurement of the integrated cross section of 110Pd(γ,n)109mPd, 110Pd(γ,n)109gPd, and 110Pd(γ,x)108mRh reactions with 70 MeV bremsstrahlung

We measured the integrated cross sections of 110Pd(γ,n)109mPd, 110Pd(γ,n)109gPd and 110Pd(γ,x)108mRh reactions in the energy range from the reaction threshold to 70 MeV bremsstrahlung end-point energy. Measurements were performed by means of the activation method in combination with off-line γ-ray spectrometry. The induced activity of radionuclides was measured with a high-purity germanium (HPGe) detector and necessary corrections for γ-ray interferences were made. The integrated cross section of the studied reactions was measured relative to that of the monitor reaction 27Al(γ,2pn)24Na. Current results are compared with theoretical predictions using the TALYS-1.9 statistical nuclear model code. Calculations were performed using six different level density models in combination with eight γ-strength functions to determine which combinations best fit the experimental results. The present results are measured for the first time.

Nuclear model analysis and optimization of production data of the medically interesting 66,67,68 Ga via alpha induced reactions on 63,65 Cu targets

Evaluation of the 63Cu(α,n)66Ga, 65Cu(α,2n) 67Ga and 65Cu(α,n)68Ga reactions was done to study the production of medical radionuclides 66Ga, 67Ga and 68Ga respectively. 63Cu(α,2n)65Ga and 65Cu(α,3n)66Ga reactions were also evaluated for the estimation of radioisotopic impurities. Cross section data of each reaction were compiled and normalized to the standard values of decay data and monitor reaction. To check the consistency of the literature data, three nuclear model calculations were performed, using nuclear model codes; TAYLS 1.9, ALICE-IPPE, and EMPIRE 3.2. A well-developed evaluation methodology based on the normalized experimental data and nuclear model calculations was used to generate the statistically fitted cross sections. From the fitted cross sections, thick target yields for each reaction were calculated for the estimation of radioisotopic impurities. Finally, a suitable energy region for the production of 66Ga, 67Ga and 68Ga was suggested with a minimum level of radioisotopic impurities.

Multiparticle natSr(γ, ) reactions induced with bremsstrahlung end-point energies of 55, 60, and 65 MeV * *Supported by the National Research Foundation of Korea through a grant provided by the Ministry of Science and ICT (NRF-2017R1D1A1B03030484, NRF-2018R1A6A1A06024970)

This study measured the yields of the radionuclides 82Sr, 83(m+g)Sr, 85mSr, 85gSr, 87mSr, 81(g+0.976m)Rb,82mRb,83gRb,84(m+g)Rb, and 86(m+g)Rb produced in natSr(γ, xnyp) multiparticle reactions with bremsstrahlung end-point energies of 55, 60, and 65 MeV. The bremsstrahlung radiation was generated using the 100-MeV electron linear accelerator at the Pohang Accelerator Laboratory, Korea, and the reaction yields were derived from the induced activitiesmeasured using off-line γ-ray spectrometry. To obtain accurate experimental results, we performed the necessary γ-rayinterference corrections. The experimental results were compared with the theoretical predictions obtained usingthe TALYS-1.95 statistical nuclear model code. The calculations were performed using six different level-density models to ascertain which model best fitted the experimental results. The dependence of the reaction yield on the incident bremsstrahlung energy and on the number of nucleons emitted by the photonuclear reactions was also investigated.

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

Nuclear data generation by machine learning (I) application to angular distributions for nucleon-nucleus scattering

ABSTRACT In order to increase the efficiency of nuclear data evaluation, we have tested a combination of a nuclear reaction model and machine learning algorithm. We calculated nucleon-nucleus elastic scattering angular distributions by using the nuclear reaction model code, and optimized the potential parameters of an optical model to reproduce experimental data by means of the Bayesian optimization. We present optimization cases with the single parameter and two or more parameters, and show that our framework gives the angular distributions that are in good agreement with the observed ones.

Measurement of the natDy(p,x) nuclear reactions cross-sections

Excitation functions of the reactions natDy(p,x)159m+gHo, 161m+gHo, 162mHo, 162gHo, 155m+gDy, 157m+gDy, 159m+gDy, 155Tbcum, 155Tb, 156Tbcum, 160Tb, 161Tb, 159m+gGd were measured in the energy range of 7.4–35.9 MeV using the stacked foil technique and off-line γ-ray spectrometry. The obtained cross-sections were compared with previously published experimental data and prediction of the TALYS nuclear reaction model code adopted from the TENDL-2019 library. Thick target yields were calculated from the experimental data.

Nuclear reaction data for medical and industrial applications: recent contributions by Egyptian cyclotron group

Abstract Measurement and evaluation of nuclear data of radioisotopes used as tracers are continuously underway in many laboratories to reach high accuracy for their use in production. We briefly mention some of the radionuclides useful for medical diagnostics and other industrial applications. The research group at the Egyptian cyclotron facility (EGCF) performed in collaboration with nuclear research centres and universities in many countries (Germany, Hungary, Finland, USA, Japan and Saudi Arabia) some measurements and evaluations of interesting nuclear reaction data. Nuclear reactions induced by p, d and α-particles on a wide variety of targets were extensively studied from threshold energy up to 50 MeV. Nuclear model code calculations, mainly using EMPIRE and TALYS, were performed for nuclear data validation. Proton and neutron activation of some industrially interesting samples were also studied as technological application of nuclear analytical techniques. Since the cyclotron facility is dedicated to development of the production routes of medical radioisotopes, this overview presents examples of optimization experiments to establish good production conditions.