92mNb Reactions Research Articles

Problems on copper data above 10 MeV in ENDF/B-VIII.0 and JEFF-3.3

We performed a benchmark test for the recent nuclear data libraries of copper data using the integral experiment at JAEA/FNS. So far, we had pointed out that the copper data might have wrong cross section data of elastic scattering and/or capture reactions around a few keV because the calculated results sensitive to lower energy neutrons with JENDL-4.0, ENDF/B-VIII.0 and JEFF-3.3 showed a tendency to underestimate the experimental ones drastically. Recently, we found out another problem that the calculated results with ENDF/B-VIII.0 and JEFF-3.3 copper nuclear data underestimated and overestimated the experimental ones related to high energy neutrons above 10 MeV such as the 93Nb(n,2n)92mNb reaction rate, respectively. These tendencies did not appear in the calculation results with their previous versions, ENDF/B-VII.1 and JEFF-3.2. In this study, we compared the 63Cu and 65Cu data in ENDF/B-VIII.0 and JEFF-3.3 with those in ENDF/B-VII.1 and JEFF-3.2, respectively, and clarified how specific reaction data caused the underestimation and overestimation by replacing them from the current ones to the previous ones. The copper data in ENDF/B-VIII.0 and JEFF-3.3 should be re-evaluated by reference to this study.

Fission cross-section measurements for the 238U(n,f)97m+gNb, 238U(n,f)133gTe and 238U(n,f)130gSb reactions induced by D-T neutrons

In this study, we conducted measurements of the independent fission cross-sections of 238U(n, f)97m+gNb, 238U(n, f)133gTe reactions and the cumulative cross section of 238U(n, f)130gSb reactions induced by neutron at energies around 14 MeV, i.e., 14.1 ± 0.3, 14.5 ± 0.3 and 14.7 ± 0.3 MeV. The measurement results were obtained by the neutron activation method in combination with off-line γ-ray spectrometry techniques. The neutron flux was monitored on line by the accompanying α-particle from T(d, n)4He reaction, and the neutron energies were determined by the cross-section ratio of 90Zr(n, 2n)8+gZr to 93Nb(n, 2n)92mNb reactions. The independent fission cross-sections of the fission reactions were obtained by subtracting the influence of precursor nuclei or excited states. The obtained results are as follows: for 238U(n, f)97m+gNb, the independent cross sections are 1.0 ± 0.89, 0.98 ± 0.85 and 0.78 ± 0.70 mb at the specified neutron energy points. For 238U(n, f)133gTe, the independent fission cross-sections are 26.8 ± 2.8, 27.7 ± 2.9 and 20.5 ± 2.3 mb, respectively, at the same neutron energy points. As for 238U(n, f)130gSb, the obtained cumulative fission cross-sections are 5.35 ± 0.58, 5.05 ± 0.53 and 4.03 ± 0.44 mb, respectively, at the specified neutron energy points.

Measurement of nuclide production cross sections for proton-induced reactions on [formula omitted]Ti and 93Nb at 0.8 and 3.0 GeV

The nuclide production cross sections for proton-induced reactions on natTi and 93Nb at 0.8 and 3.0 GeV were measured using an activation technique at Japan Proton Accelerator Research Complex. A total of 27 and 94 nuclide production cross sections for the natTi(p,X) and 93Nb(p,X) reactions were obtained, respectively. Cross sections of the natTi(p,X)44Sc, 93Nb(p,X)52Mn, 93Nb(p,X)69mZn, 93Nb(p,X)82mRb, 93Nb(p,X)85mY, 93Nb(p,X)87mY, 93Nb(p,X)90mY, 93Nb(p,X)91mNb, 93Nb(p,X)92mNb, and 93Nb(p,X)93mMo reactions were successfully measured for the first time. In addition, the cross sections of the natTi(p,X)46Sc, 93Nb(p,X)73As, 93Nb(p,X)85Y, and 93Nb(p,X)87Y reactions above about 1 GeV were firstly measured. The present data were compared with the results from nuclear reaction models in PHITS and data retrieved from Japanese Evaluated Nuclear Data Library High Energy file 2007 (JENDL/HE-2007). As the nuclear reaction models, Liège IntraNuclear Cascade (INCL), two versions of JAERI Quantum Molecular Dynamics, and Jet AA Microscopic Transport Model coupled with an evaporation process were applied. The prediction accuracy of JENDL/HE-2007 was the best for the 7Be production cross section of both targets. As an overall trend, underestimation of INCL and all of the models were confirmed for the natTi(p,X) and 93Nb(p,X) reactions, respectively.

Measurement of 169Tm(n, 2n)168Tm reaction cross sections from 12 to 19.8 MeV* *Supported by the National Natural Science Foundation of China (12075216)

The cross sections of the 169Tm(n, 2n)168Tm reaction have been measured at incident energies of 12 to 19.8 MeV using the activation technique, relative to the 93Nb(n, 2n)92mNb reaction. Thulium (Tm) samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the 3H(d, n)4He reaction at the 5SDH-2 1.7-MV Tandem accelerator in China. Theoretical model calculations were performed. The present data were then compared with previous experimental data and available evaluated data. This study provides more precise nuclear data for improvement of future evaluations.

Measurement of the [formula omitted] and [formula omitted] reaction cross-sections and isomeric ratios induced by the 14.8 MeV neutrons

The precise measurement of the (n, 2n) reaction cross-sections of xenon isotopes is of great significance for the diagnosis of the Inertial Confinement Fusion fuel area density ρR. The preparation of xenon samples and how they can be efficiently adsorbed to obtain an optimal reaction cross section are extremely difficult in existing experiments. This work aims to use the 93Nb(n,2n)92mNb reaction cross section as the standard to calculate the cross-sections and isomeric ratio for 134Xe(n,2n)133m,gXe and 136Xe(n,2n)135m,gXe reactions. This work also aims to explore the feasibility of adsorbent selection, the method of adsorption sample and the feasibility of the method used in the laboratory. In this paper, the Geant4 program was used to simulate and calculate the adsorption factors of activated carbon and polymer for standard 152Eu multi-line sources, so as to determine the most suitable adsorption material. Next, the GammaVision analysis software was used to observe whether the characteristic γ-rays released by other isotope reaction products of xenon in the sample and packaging material had an effect on the characteristic γ-rays of the target product. Then, the basic principle of activation method and the relative measurement principle are used to calculate the cross-sections and isomeric ratio for 134Xe(n,2n)133Xe and 136Xe(n,2n)135Xe reactions. Finally, the experimental results are compared and analyzed with the existing data in EXFOR database to verify whether the experimental method is correct.

Measurement of the (n, 2n) reaction cross-sections of iodine and cesium induced by D-T neutrons with covariance analysis* *Supported by the Key Laboratory of Nuclear Data Foundation (JCKY2022201C151), and the National Natural Science Foundation of China (11975113).

The cross-sections of the 127I (n, 2n) 126I and 133Cs (n, 2n) 132Cs reactions at neutron energies of 13.83 ± 0.05, 14.33 ± 0.10, and 14.79 ± 0.10 MeV were measured relative to the 93Nb (n, 2n) 92mNb reaction using the activation technique in combination with off-line γ-ray spectrometry. A neutron beam was generated from the T (d, n) 4He reaction using the K-400 neutron generator at the China Academy of Engineering Physics. Considering the correlations between different attributes, detailed uncertainty propagation was performed using covariance analysis, and the cross-sections were reported with their uncertainties and correlation matrix. The uncertainty of the measurement cross-sections ranged from 4.84 to 5.90%, which is lower than previous experimental data. Furthermore, the theoretical excitation functions of the 127I (n, 2n) 126I and 133Cs (n, 2n) 132Cs reactions were calculated using the TALYS-1.95 and EMPIRE-3.2.3 codes. Then, the experimentally determined cross-sections were analyzed by comparing them with literature data available in the EXFOR database and evaluated nuclear data in the ENDF/B-VIII.0, JEFF-3.3, JENDL-5, BROND-3.1, CENDL-3.2, and TENDL-2021 databases. Compared with the values previously reported in the 13.8-14.8 MeV energy region, the precision of the results obtained in this study was greatly improved. The current experimental results with thorough uncertainties and covariance information are critical for verifying the reliability of the theoretical model and improving the quality of the nuclear database.

Activation cross sections for reactions induced by 14 MeV neutrons on natural titanium

Cross sections for the neutrons around 14 MeV interaction with natural titanium were precisely measured by neutron activation and off-line measurement technique. The fast neutrons were produced by 3H(d,n)4He reaction and the neutron energy was obtained by using the cross section ratio method of 90Zr(n,2n)89Zr to 93Nb(n,2n)92mNb reactions. Experimental cross sections have been acquired for natTi(n,x)46Sc, natTi(n,x)47Sc, 50Ti(n,x)47Ca and 48Ti(n,x)48Sc reactions. The measured cross section data are compared with the experimental data available in the previous literature and evaluated nuclear data from the ENDF/B-VIII.0, JEFF-3.3, JENDL-5, BROND-3.1, CENDL-3.2 and FENDL-3.2b libraries. Furthermore, excitation functions for these reactions were calculated by using the theoretical model based on Talys-1.96 code with default and adjusted parameters. Within experimental error, evaluated nuclear data are mostly consistent with experimental data. The excitation function with adjusted parameters can roughly reproduce the experimental data.

Cumulative fission yield measurements with 14.7 MeV neutrons on 238U* *Supported by the National Natural Science Foundation of China (11975113)

The fission yield data in the 14 MeV energy neutron induced fission of 238U play an important role in decay heat calculations and generation-IV reactor designs. In order to accurately measure fission product yields (FPYs) of 238U induced by 14 MeV neutrons, the cumulative yields of fission products ranging from 92Sr to 147Nd in the 238U(n, f) reaction with a 14.7 MeV neutron were determined using an off-line γ-ray spectrometric technique. The 14.7 MeV quasi-monoenergetic neutron beam was provided by the K-400 D-T neutron generator at China Academy of Engineering Physics (CAEP). Fission products were measured by a low background high purity germanium gamma spectrometer. The neutron flux was obtained from the 93Nb (n, 2n)92mNb reaction, and the mean neutron energy was calculated using the cross-section ratios for the 90Zr(n, 2n)89Zr and 93Nb(n, 2n)92mNb reactions. With a series of corrections, high precision cumulative yields of 20 fission products were obtained. Our FPYs for the 238U(n, f) reaction at 14.7 MeV were compared with the existing experimental nuclear reaction data and evaluated nuclear data, respectively. The results will be helpful in the design of a generation-IV reactor and the construction of evaluated fission yield databases.

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.

Cross section measurements of (n, α) (n, n'α) and (n, p) reactions for 65Cu at 14 MeV neutrons

The cross sections of the 65Cu(n, α)62mCo, 65Cu(n, n'α)61Co and 65Cu(n, p)65Ni reactions have been measured relative to 56Fe(n, p)56Mn reaction at 14 MeV neutron energy through neutron activation method followed by off-line γ-ray spectrometry. The 14 MeV neutrons were produced via the 3H(d, n)4He fusion reaction based on K-400 D-T neutron generator at China Academy of Engineering Physics (CAEP). The neutron energies were determined by the cross-section ratios for the 90Zr(n, 2n)89Zr and 93Nb(n, 2n)92mNb reactions. The cross sections measured in the present work are compared with the earlier reported cross sections available in the EXFOR database, evaluated nuclear data and theoretical results calculated by TALYS-1.95 code.

The cross section measurements of 131X produced in 238U(n,f) reaction induced by 14 MeV neutron

The cross sections of 131Sb and 131gTe produced from the 238U(n,f) reaction around the neutron energy of 14 MeV were measured by using γ-ray spectrometry with a low background HPGe detector. During the irradiating time, the neutron flux of T(d,n)4He reaction was monitored by following the α-particle. The cross-section ratio of 90Zr(n,2n)89Zr to 93Nb(n,2n)92mNb reaction was used in the determination of neutron energy varied with the emission angle. In the process of calculating results, the Al was used as monitor to eliminate the influence of neutron flux. The obtained fission cross-sections at the neutron energies of 14.1 ± 0.3, 14.5 ± 0.3, and 14.7 ± 0.3 MeV are 31.11 ± 1.72, 29.63 ± 1.80, and 25.56 ± 1.71mb for 238U(n,f)131Sb reaction and 21.82 ± 1.05, 20.40 ± 1.07, and 17.05 ± 0.98 mb for 238U(n,f)131gTe reaction, respectively.

Measurement of the 124Xe (n,2n) reaction cross section induced by 14.8 MeV neutron

The measurement of the 124Xe(n, 2n)123Xe reaction cross section at 14.8 MeV neutron has been performed by the activation method. Quasi monoenergetic neutron beams were produced at the Cockcroft Walton Accelerator of China Institute of Atomic Energy, by the T(d, n)4He reaction. A cell made of polymethyl methacrylate (PMMA) was used as the container of 124Xe (99.95% abundance) gas, and the mass of 124Xe in cell was determined by weighing method. Two high-purity thin 93Nb foils were attached to the cell and performed as monitors of the neutron flux determination by 93Nb(n, 2n)92mNb reaction. After the irradiation, the activities of 123Xe and 92mNb were measured by off-line gamma-ray spectrometric technique using a pre-calibrated HPGe detector. As a result, the cross section has been deduced at 14.8 MeV, and the result was compared with the literature data and evaluations.

Cross section measurements for (n,2n), (n,α), and (n,p) reactions on rhenium isotopes around 14 MeV neutrons and their theoretical calculations of excitation functions* *Supported by National Natural Science Foundation of China (11605099, 11575090)

Cross-section data of the 185Re(n,2n)184mRe, 185Re(n,2n)184gRe, 185Re(n,α)182m1+m2+gTa, 187Re(n, 2n)186g,(m)Re, 187Re(n,α)184Ta, and 187Re(n,p)187W reactions were measured at four neutron energies, namely 13.5, 14.1, 14.4, and 14.8 MeV, by means of the activation technique, relative to the reference cross-section values of the 93Nb(n,2n)92mNb reaction. The neutrons were generated from the T(d,n)4He reaction at the K-400 Neutron Generator at China Academy of Engineering Physics. The induced γ activities were measured using a high-resolution γ-ray spectrometer equipped with a coaxial high-purity germanium detector. The excitation functions of the six above-mentioned nuclear reactions at neutron energies from the threshold to 20 MeV were calculated by adopting the nuclear theoretical model program system Talys-1.9 with the relevant parameters properly adjusted. The measured cross sections were analyzed and compared with previous experiments conducted by other researchers, and with the evaluated data of BROND-3.1, ENDF/B-VIII.0, JEFF-3.3, and the theoretical values based on Talys-1.9. The new measured results agree with those of previous experiments and the theoretical excitation curve at the corresponding energies. The theoretical excitation curves based on Talys-1.9 generally match most of experimental data well.

Copper neutron transport libraries validation by means of a 252Cf standard neutron source

Copper is an important structural material in various nuclear energy applications, therefore the correct knowledge of copper cross sections is crucial. The presented paper deals with a validation of different copper transport libraries by means of activation of selected samples. An intense 252Cf(sf) source with a reference neutron spectrum was used as a neutron source. After irradiation, the samples were measured using a high purity germanium detector and the dosimeter reaction rates were inferred. These experimental data were compared with MCNP6 calculations using CENDL-3.1, JENDL-4.0, ENDF/B-VII.1, ENDF/B-VIII.0, JEFF-3.2 and JEFF-3.3 evaluated Cu transport libraries. The experiment specifically focuses on 58Ni(n,p)58Co, 93Nb(n,2n)92mNb, 197Au(n,g)198Au and 55Mn(n,g)56Mn dosimetry reactions. Evaluated activation cross sections of these dosimetric reactions were taken from the IRDFF-II library. The best library performance depends on the energy region of interest.

Measurements of secondary-particle emissions from copper target bombarded with 24-GeV/c protons

To devise an activation technique for characterizing mixed radiation fields, secondary particles from a copper target irradiated by 24 GeV/c protons were measured at the CERN High-energy AcceleRator Mixed field facility (CHARM). Activation detector sets consisting of aluminum, niobium, indium, and bismuth, were placed at 30 cm from the target at angles of 15° to 160° with respect to the beam axis. The nuclides generated in these detectors due to irradiation by secondary particles were analyzed by γ-ray spectrometry, and the angular distributions of the production rates were obtained. The results of Monte Carlo calculations using FLUKA code was compared with the experimental results. The calculated results well agreed with the measured data at all angles. The influence of competitive reactions on the measured data were also evaluated by FLUKA. The following nuclear reactions, with low affectivity by competitive reactions, were identified as promising tools for characterizing mixed radiation fields: the 115In(n, n′)115mIn reaction for detecting neutrons emitted by the evaporation process, the 93Nb(γ, n)92mNb reaction for verifying the photon distribution generated by neutral-pion decay (π0→2γ), and the 209Bi(p, 4n)206Po reaction, which detects secondary protons.

Cross-section measurement for (n,2n) reaction induced by 14 MeV neutron on platinum isotopes

Neutron induced the (n, 2n) reaction cross sections of platinum isotopes (190Pt, 192Pt, 196Pt and 198Pt) were well measured by the neutron activation and off-line gamma-ray technique around neutron energy of 14 MeV. During the irradiating time, the flux fluctuation of generating neutron was monitored by accompanying α-particle, while the cross section-ratio of 90Zr (n, 2n)89Zr to 93Nb(n, 2n)92mNb reactions were used to determine the neutron energies, which varied with the emission angle. As a result, the cross sections of 190Pt (n, 2n)189Pt, 192Pt (n, 2n)191Pt, 196Pt (n, 2n)195mPt, 198Pt (n, 2n)197mPt and 198Pt (n, 2n)197gPt reactions have been deduced at En = 14.1 ± 0.2 MeV, 14.5 ± 0.2 MeV and 14.7 ± 0.1 MeV, respectively. Meanwhile, the comparisons between this work and the literature date were given, as well as evaluated nuclear data and simulation data (ENDF/B-VIII.0, JEFF 3.3, ROSFOND-2010, JENDL/AD-2017 and Talys 1.9). The results shows an agreement with literature work as a whole, except the 196Pt (n, 2n)195mPt reaction.

Cross-sections for , and reactions on molybdenum isotopes in the neutron energy range of 13 to 15 MeV * * Supported by the National Natural Science Foundation of China (11875016, 11565012, 11165007)

Given the insufficient cross-sectional data regarding the 14-MeV-neutron experiment of molybdenum, the vital fusion reactor structural material, and the significant heterogeneities among the reported values, this study examined the (n,2n), (n,α), (n,p), (n,d), and (n,t) reaction cross sections in molybdenum isotopes based on the neutrons produced via a T(d,n)4He reaction carried out in the Pd-300 Neutron Generator at the China Academy of Engineering Physics (CAEP). A high-resolution gamma-ray spectrometer, which was equipped with a coaxial high-purity germanium detector, was used to measure the product nuclear gamma activities. In addition, 27Al(n,α)24Na and 93Nb(n,2n)92mNb reactions were utilized as the neutron fluence standards. The experimental 92Mo(n,2n)91Mo, 94Mo(n,2n)93mMo, 100Mo(n,2n)99Mo, 98Mo(n,α)95Zr, 100Mo(n,α)97Zr, 92Mo(n,p)92mNb, 96Mo(n,p)96Nb, 97Mo(n,p)97Nb, 98Mo(n,p)98mNb, 92Mo(n,d)91mNb, and 92Mo(n,t)90Nb reaction cross sections were acquired within the 13–15 MeV neutron energy range. Thereafter, we compared and analyzed these obtained cross sections based on the existing IAEA-EXFOR database-derived experimental data, together with evaluation results corresponding to ENDF/B-VIII.0, JEFF-3.3, BROND-3.1, and CENDL-3.1 and the theoretical outcomes acquired through TALYS-1.95 and EMPIRE-3.2.3 (nuclear-reaction modeling tools).

Measurement of 14.54 ± 0.24 MeV neutron activation reaction cross sections of 93Nb, natMo with covariance analysis

The 93Nb(n,α)90mY, 93Nb(n,2n)92mNb and 92Mo(n,p)92mNb reaction cross sections have been measured relative to the 197Au(n,2n)196Au monitor reaction at the neutron energy of 14.54 ± 0.24 MeV. The neutrons were generated from the T(d,n)4He reaction using Purnima neutron generator. The experiment was done by using the method of activation in combination with an off-line $$\gamma$$ -ray spectrometry technique. The uncertainties and correlations for the reaction cross sections were estimated with the use of covariance analysis by considering the partial uncertainties in individual attributes. The measured reaction cross sections have been analyzed by comparing with the data available in EXFOR compilation, various files of evaluated data and theoretically calculated values from TALYS-1.9.

Measurement of fission cross sections for 232Th(n,f)[formula omitted] reaction around the neutron energy of 14 MeV

Neutron induced fission cross sections of 232Th(n,f)84Se, 232Th(n,f)84mBr, 232Th(n,f)84gBr reactions were measured based on neutrons from the D-T source. The α-particles emitted from the T(d,n)4He reaction were measured to monitor the neutron flux, while the ratio of 90Zr(n,2n)89Zr to 93Nb(n,2n)92mNb reactions was used to determine the neutron energy. The gamma-ray activity of samples was measured with a well calibrated HPGe-γ detector. In the 232Th(n,f) reaction at the neutron energies of 14.1 ± 0.3, 14.5 ± 0.3 and 14.7 ± 0.1 MeV, the cross sections are 2.74 ± 0.23, 2.75 ± 0.25, and 2.30 ± 0.21 mb for 84mBr, 3.41 ± 0.37, 3.35 ± 0.37, and 3.81 ± 0.42 mb for 84gBr, and roughly 8.79 ± 0.58, 9.36 ± 0.62, and 9.26 ± 0.62 mb for 84Se, respectively.

CROSS-SECTIONS FOR PHOTONUCLEAR REACTIONS 93Nb(γ,n)92mNb AND 93Nb(γ,n)92tNb IN THE END-POINT BREMSSTRAHLUNG ENERGIES 36...91 MeV

The flux-weighted averaged over the energy range of bremsstrahlung spectrum from reaction threshold up to the maximum energy of γ-ray cross-sections <σ(E)> of the 93Nb(γ,n)92mNb and 93Nb(γ,n)92tNb photonuclear reactions were determined by the gamma-activation method within the end-point bremsstrahlung energies Еmax = 36…91 MeV. Activation of 93Nb targets has been done by a bremsstrahlung flux using an electron beam at the linear accelerator LUE-40 at RDC "Accelerator" NSC KIPT. The γ-ray spectra of irradiated targets were registered using the HPGe detector with an energy resolution of 1.8 keV for the 1332 keV line 60Co. To control the bremsstrahlung flux we used natMo witness-targets and a reaction cross-section of 100Mo(γ,n)99Mo. Obtained experimental cross-sections <σ(E)> of the studied reactions are in good agreement with the theoretical values calculated within TALYS 1.9 code and the results of other authors. The averaged cross-sections <σ(E)> of the 93Nb(γ,n)92mNb and 93Nb(γ,n)92tNb reactions in the energy range 35...45 MeV and > 70 MeV were obtained for the first time.