Activation Cross Sections Research Articles

Experimental measurements and theoretical calculations of excitation functions of 103Rh(α,xn)106m,105g,104gAg and 103Rh(α,αxn)101m,102gRh reactions up to 40 MeV

Activation cross sections of 103Rh(α,xn)106m,105g,104gAg and 103Rh(α,αxn)101m,102gRh radionuclides were measured at energies ranging from their respective threshold energies up to 40 MeV. Standard stacked foil activation technique was employed for irradiation. Residual activity was assayed using high-resolution gamma-ray spectrometry. Excitation functions were also theoretically calculated using TALYS nuclear reaction model to reproduce the experimental cross section data. The present data are compared with the available literature data, TENDL-2023 data using default values as well as the theoretical data calculated by TALYS-1.96. The shape and amplitude of the experimentally obtained excitation functions were well reproduced theoretically for all the studied radionuclides except for 105gAg, for which magnitude of the cross sections was not reproduced. The integral yields were also deduced using the measured cross sections and the stopping power of natural Rh from 40 MeV down to their threshold energies for these radionuclides, and compared with the experimental yield data available in the literature.

Activation cross section for 85Rb(n,2n)84mRb and 85Rb(n,p)85mKr reactions with uncertainty propagation and covariance analysis

The cross section of 85Rb(n,2n)84mRb and 85Rb(n,p)85mKr reactions were measured at neutron energy range 12–20 MeV using activation analysis followed by off-line γ-ray spectroscopic technique. The quasi mono-energetic neutrons were produced through 7Li(p,n)7Be reaction. The measurements were done relative to 27Al(n,α)24Na reference monitor reaction cross section. The detailed uncertainty propagation from the attributes present in measurements was performed using covariance analysis. The γ-ray self-attenuation and background low neutron energy corrections were performed in the measurement studies. Theoretical calculations were performed by TALYS-1.96 nuclear code. The comparison of measured values with the available data in EXFOR database and evaluated data from JENDL-5 and EAF-2010 shows the measured cross section values of 85Rb(n,p)85mKr reaction were slightly higher than the published values, evaluated data and theoretical data while for 85Rb(n,2n)84mRb, the measured values were consistent with the published data.

Activation cross sections of alpha-particle-induced reactions on natural rhenium up to 50 MeV

Activation cross sections of alpha-particle-induced reactions on natural rhenium were measured. The stacked-foil activation technique and high-resolution gamma-ray spectrometry were used to derive the cross sections. The production cross sections of 190g, 189g, 188g, 187g, 186g, 185, 184Ir, 185Os, and 184g, 183gRe were determined up to 50 MeV. The cross sections of 185,184Ir were measured for the first time. The experimental results were compared with previous experimental data and theoretical calculations in the TENDL-2021 library.

Excitation functions for [formula omitted]Ag(α,x) reactions with detailed covariance analysis

Natural silver targets were irradiated using an alpha particle beam to measure the activation cross sections of radioisotopes within the energy range of 23–40 MeV. The newly obtained cross section data, compared with previous experimental results, underline the importance of this work in the context of nuclear reactions and medical applications. Alpha particle induced reaction with natAg involved the production of radioisotopes such as 111In, 105Ag, 106mAg. In this study, we focused on calculating correlation matrices for the natAg(α,x) nuclear reactions. These matrices were generated by considering various interconnected variables, such as decay constants, particle number densities, γ-ray intensities and detector efficiencies for both monitor and sample nuclear reaction products.

Activation cross sections of 7Li-induced reactions on natCu for monitor reactions

Activation cross sections of 7Li-induced reactions on natCu were measured in order to investigate suitability of some reactions for monitoring experimental parameters. Cross sections producing 69,68Ge, 67,66Ga and 69m,65Zn were determined. Physical thick target yields were experimentally measured and compared with those calculated using the measured cross sections. The measured cross sections were verified by the agreements between the directly measured thick target yields and the thick target yields deduced from the measured cross sections. The 7Li-induced reactions on natCu for the production of 67,66Ga and 65Zn are suggested as monitor reactions.

Study of activation cross sections of double neutron capture reaction on 193Ir for the reactor production route of radiotherapeutic 195mPt

The radiotherapeutic 195mPt is among the most effective Auger electron emitters of the currently studied radionuclides that have a potential theranostic application in nuclear medicine. Production of 195mPt through double neuron capture of enriched 193Ir followed by β−-decay to the radioisotope of interest carried out at the research reactor IBR-2 is described. Because of the high radiation background, radiochemical purification procedure of 195mPt from bulk of iridium was needed to be developed and is detailed here as well. For the first time, cross section and resonance integral for the reaction 194Ir(n,γ)195mIr were determined. Resonance neutrons contribution was established to exceed that of thermal neutrons, and resonance integral for the reaction 194Ir(n,γ)195mIr is calculated to be 2900 b. Specific activity of 195mPt was estimated to reach a value of 38.7 GBq/(g Pt) at IBR-2 by the end of bombardment (EOB).

Excitation functions of the α-particle-induced reactions on natCr up to 50 MeV

Activation cross sections of the α-particle-induced reactions on natCr were measured. A stacked foil activation technique and γ-ray spectrometry were used. Nickel-chromium alloy, nickel and titanium metallic foils were stacked as a target. The target was irradiated with a 51.2-MeV α-particle beam at the AVF cyclotron, RIKEN. The γ rays were measured for the irradiated foils using an HPGe detector. Production cross sections of 52gFe, 52g,54Mn, 48,51Cr and 48V radionuclides were determined. The cross sections determined in this experiment were compared with the literature data and found to be consistent with them.

Activation cross sections of α-particle-induced reactions on scandium in the energy range of 22–51 MeV

Activation cross sections of α-particle-induced reactions on scandium were measured in the energy range between 22 and 51 MeV. The experiment was performed with a 51-MeV α-particle beam at the RIKEN AVF cyclotron. The stacked-foil activation technique and γ-ray spectrometry were used. Cross sections for the formation of 48V, 45Ti, 47,46m+g,44m,44g,43gSc, and 43,42K were obtained. The production cross sections of 45Ti, 42K, and 43K were measured for the first time.

Activation cross sections for the formation of 51Cr and 52,54Mn in interactions of deuterons with iron

Abstract Excitation functions for the formation of the radionuclides 51Cr, 52Mn and 54Mn via deuteron-induced activation of natural iron were measured up to deuteron energies of 35 MeV. The available experimental databases of the reaction products 51Cr, 52Mn and 54Mn were extended and compared with the nuclear model calculations using the TALYS code. The model calculations reproduce our measured data after a careful choice of the input model parameters. Some information obtained on competition between the emission of multinucleons and a bound α-particle.

Activation cross sections of proton induced nuclear reactions on tungsten: Special regard to the formation of 186Re

Cross-sections for the production of 181,182m,g,183,184g,186gRe radioisotopes from proton bombardment of natural tungsten have been measured using the stacked foil activation technique for proton energies up to 14.7 MeV. The results were analyzed and compared with the reported experimental data, and the theoretical excitation functions as calculated by the EMPIRE 3.2.3 and TALYS 1.9 codes. Several attempts have been made to reproduce the experimental excitation functions by different EMPIRE input parameters, and a reasonable agreement was attained. While measuring the activity of radionuclide 181Re, the intensity of the emitted 360-keV γ-photon was estimated at around 10 %, about half of the value reported in various databases. The integral yield of the investigated radioisotopes has been calculated, and a particular interest in the 186gRe therapeutic radionuclide was discussed.

The fast neutron fluence and the activation monitor activity calculations using fine multigroup and continuous nuclear data

The fast neutron fluence and the activation monitor activities are routinely calculated with TORT deterministic code and BUGLE-B7 nuclear data library with 47 broad energy groups. The objective of the paper is to analyse options to improve reactor dosimetry transport calculations. There are two paths to improve reactor dosimetry calculations. Increasing geometry, angular and energy mesh size is applicable for TORT code while using newer nuclear data libraries is relevant for both deterministic and Monte Carlo codes. Two new calculation options (improved TORT and Monte Carlo MCNP6) were compared with the standard TORT calculation for VVER-440 Dukovany Unit 3 Cycle 31. The fast neutron fluence with 0.5 MeV threshold as well as activity of Fe. Ni, Ti, Cu. Mn and Nb monitors were evaluated. Standard TORT calculations were improved from S16P3 to S30P3 with three times finer axial mesh size. 120° core symmetry r-ϑ mesh size with 0.5° step and fine multigroup libraries VUAMIN-B7 with 199 neutron energy groups and ENDF/B-VH.1 with 200 neutron energy groups. Both ENDFB and IRDFF activation cross sections were used. The drawback of expanded mesh size is raised calculation runtime since TORT deterministic code is not parallelized and one calculation can require multiple weeks of CPU time. An alternative option of using MCNP6 Monte Carlo code with continuous ENDF/B-VH.1 nuclear data with detailed 3-D geometry and pin-wise effective neutron source prepared by MOBY-DICK diffusion code reactor analysis wras explored. It was found that using finer mesh size affects reactor dosimetry’ tallies less than the choice of nuclear data library. BUGLE-B7 and VTTAMIN-B7 produce results typically within 1% difference. ENDF/B-VH.1 calculations with 200 neutron energy’ groups with TORT code are even in better agreement with MCNP6 calculations with continuous nuclear data libraries. The largest differences of around 2% were observed between VTTAMIN-B7 library based onENDFB-VH.O nuclear data and ENDF/B-VH.1 library. Nuclear data library’ has larger impact on the results with up to 7 % difference between all 0.5 MeV fast neutron fluence calculations. The largest intact of nuclear data was observed for Mn(n.2n) monitor.

Due consideration of the breakup and direct reaction mechanisms within (d, p), (d, 2p), (d, xn2p), and (d, xn) reactions

Suitable account of available excitation-function of deuterons interaction with target nuclei components of candidates materials for the ITER fusion reactor, the European DEMO fusion reactor, and the IFMIF-DONES Irradiation Facility has been proved by consistent analysis of the reaction mechanisms involved in the complex deuteron-nucleus interaction. In this work the attention has been focused on the analysis of the deuteron activation cross sections related to the gas accumulation, (d, p), (d, 2p), (d, xn2p), and to the strong neutron emission, (d, xn), interaction processes of interest for the radiation damage and shielding design studies devoted to the structural materials selection. The key role of direct interactions, i.e., breakup, stripping and pick-up processes is stressed out by the comparison of data with theoretical and evaluation predictions.

Characterization of a HPGe detector response for activation cross section measurements: regression method versus Monte Carlo method

ABSTRACT The full energy peak efficiencies and covariances of a high purity germanium (HPGe) detector studied by the regression method and Monte Carlo method were compared. The impact of the obtained results on the neutron activation cross-sections measured relative to monitor cross-sections was studied. In the regression method, the efficiencies measured for a set of calibration point sources were analysed by the least-squares analysis. In the Monte Carlo method, the efficiencies for the calibration point sources were calculated by MCNP. The covariances of the efficiencies determined by the regression method were calculated analytically. Perturbation analysis was performed to estimate the covariances of the efficiencies calculated by the Monte Carlo method. Positive correlations higher than 0.8 were found in the uncertainties of the MCNP data for point-like sources. In the case of the regression method, the correlation coefficient contains both positive and negative terms. The efficiencies and their covariances for finite sample geometry were also estimated by both methods to take into account sample effects such as geometrical effect, and gamma-ray self-absorption, and found considerable differences in the cross-sections and their uncertainties for reaction products quantified with low energy gammas. The efficiencies and covariances were clearly affected by the properties of the sample.

Measurement of fast-neutron activation cross section of the 109Ag(n,2n)108mAg reaction and its theoretical calculation of excitation function

The cross section values of the 109Ag(n,2n)108mAg reaction at four neutron energies 13.5, 14.1, 14.4 and 14.8 Me were measured relative to those of the monitor reaction 93Nb(n,2n)92mNb by using the activation technique and using off-line γ-ray spectrometry. Fast neutrons were produced by the T(d,n)4He reaction. The excitation function of this reaction in the neutron energies from the reaction threshold to 20 MeV was obtained based on the nuclear theoretical model program system TALYS-1.95 with the adjusted relevant parameters. The measured results were discussed and compared with the experimental data of literature, and the evaluated data from the evaluated libraries of TENDL-2021 and JEFF-3.1.2, as well as with the theoretical values based on TALYS-1.95.

Activation cross section measurement of alpha-particle induced nuclear reactions on tantalum

Activation cross sections induced by 50 MeV alpha-particle beam on natural tantalum were measured at the AVF cyclotron of the Nishina Center of RIKEN. The well-established stacked target technique and activation method were applied followed by high-resolution gamma spectrometry to determine the reaction cross sections. The experiment aimed to determine activation cross sections for the longer-lived reaction product. Accordingly, activation cross sections were deduced for the formation of 181, 182m, 182g, 183, 184m, 184gRe and 178g, 182gTa.

Activation cross sections of radionuclides produced by alpha induced reactions on natCd up to 40 MeV for optimized production of 117mSn

Activation cross sections of radionuclides produced by alpha induced reactions on natCd up to 40 MeV for optimized production of 117mSn

Activation cross sections of deuteron-induced reactions on natural rhenium up to 23 MeV

Activation cross sections of deuteron-induced reactions on natural rhenium were measured using the stacked-foil activation technique and γ-ray spectrometry. Production cross sections of 185,183m,183gOs and 188g,186g,184m,184g,183gRe were determined up to 23 MeV. The derived cross sections were compared with experimental literature data and the TENDL-2019 and TENDL-2021 values.

Activation cross section for the [formula omitted] and [formula omitted] reactions on 103Rh, 48Ti and 52Cr from reaction threshold up to 25 MeV energy region

Activation and off-line γ-ray spectrometric methods were used to measure the ground and isomeric state (n,2n) reaction cross section for 103Rh at two different neutron energies. The standard 27Al (n,α)24Na reference reaction was used to normalise neutron flux. The proton beam from the 14UD BARC-TIFR Pelletron facility in Mumbai, India, was utilised to create high-energy quasi-monoenergetic neutrons via the 7Li (p,n) reaction. Statistical model calculations including the level density, pre-equilibrium and optical potential model were performed using the TALYS (ver. 1.95) and EMPIRE (ver. 3.2.3) reaction codes. In addition, because of considerable discrepancies in measured data, the literature (n,p) reaction cross section of 52Cr and 48Ti targets were examined theoretically in the present work. The measured cross sections are discussed and compared with the latest evaluated data of the FENDL-3.2b, CENDL-3.2, TENDL-2019, JENDL-5.0, and ENDF/B-VIII.0 libraries, and experimental data based on the EXFOR compilation. The theoretical investigation of the (n,2n) reaction cross section was performed for the ground and isomeric state for the first time from reaction threshold to 25 MeV energies. The experimental data corresponding to the ground, isomeric state and isomeric ratio were reproduced consistently by the theoretical calculations. The present experimental results are good with certain literature data and theoretical values.

Measurement of dosimetrical cross sections with 14.05 MeV neutrons from compact neutron generator

This paper deals with the measurement of the differential dosimetry cross sections using a small compact D-T neutron generator with 14.05 ± 0.08 MeV neutron emission (1 × 108 n/s into 4π). In spite of low neutron flux, it is possible to get measurable gamma-ray activities by irradiating a larger amount of target material placed in close geometry. The experimentally determined cross sections are in good agreement with the cross sections in the IRDFF-II dosimetry library. The comparison with other nuclear data libraries was performed as well. It is worth noting that the mean standard deviation in IRDFF-II library is about 4 %, while in the case of other data libraries they are from 5.5 % to 7.5 %. This result can be understood as a validation of IRDFF-II using 14.05 MeV neutrons and also a confirmation of the applicability of small compact generators in the measurement of activation cross sections.

Activation Cross Section Measurement of the (n,2n) Reaction on 203Tl at 16.4 MeV, 18.9 MeV and Theoretical Calculations via the EMPIRE code

The aim of the present work was to study the cross-section of the (n,2n) and (n,3n) reactions on 203Tl, by irradiating a natural TlCl pellet target with monoenergetic neutron beams at 16.4, and 18.9 MeV. The cross section measurements were carried out using the activation method, with respect to the 197Au(n,2n)196Au and 27Al(n,α)24Na reference reactions. The monoenergetic neutron beams were generated in the 5.5 MV Tandem accelerator of NCSR “Demokritos”, using the 3H(d,n)4He reaction. Monte Carlo simulations have been performed to take into account the gamma-ray self-absorption results as well as the estimation of the neutron flux through the reference foils. Theoretical calculations with the code EMPIRE have also been performed, using the same parameterization implemented in the theoretical study of Ir and Au nuclei in an attempt to find a suitable model for the description of all the experimental results in this mass region.