58Co Reaction Research Articles

Comprehensive analysis of uncertainty quantification for the 58Ni(n, p)58Co reaction cross section* *Project supported by the Scientific and Industrial Research (CSIR), Government of India (File No 09/013(882)/2019-EMR-1) for providing senior research fellowships, the IUAC-UGC, Government of India (Sanction No. IUAC/XIII.7/UFR- 71353), and Institutions of Eminence (IoE) BHU (Grant No. 6031).

In this study, we measured the 58Ni(n, p)58Co reaction cross section with neutron energies of 1.06, 1.86, and 2.85 MeV. The cross section was measured using neutron activation techniques and γ-ray spectroscopy, and it was compared with cross section data available in the EXFOR. Furthermore, we calculated the covariance matrix of the measured cross section for the aforementioned nuclear reaction. The uncertainties of the theoretical calculation for 58Ni(n, p)58Co reaction cross section were calculated via Monte Carlo method. In this study, we used uncertainties in the optical model and level density parameters to calculate uncertainties in the theoretical cross sections. The theoretical calculations were performed by using TALYS-1.96. In this study, we aim to analyze the effect of uncertainties of the nuclear model input as well as different experimental variables used to obtain the values of reaction cross section.

Investigation of 58Ni (n, p)58Co reaction cross-section with covariance analysis* *One of the authors (A.H.) sincerely acknowledges the Department of Science and Technology (DST), Government of India, for the INSPIRE Fellowship award (No. DST/INSPIRE Fellowship/2019/IF190924). G.S. and B.K.A. acknowledge partial support from the SERB, Department of Science and Technology, Government of India, with grants No. SIR/2022/000566 and CRG/2021/000101, respectively

The excitation function of the reaction was measured using the well-established neutron activation technique and γ-ray spectroscopy. Neutrons in the energy range of 1.7 to 2.7 were generated using the reaction. The neutron flux was measured using the standard monitor reaction. The results of the neutron spectrum averaged cross-section of reactions were compared with existing cross-section data available in the EXFOR data library as well as with various evaluated data libraries such as ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0, and CENDL-3.2. Theoretical calculations were performed using the nuclear reaction code TALYS. Various nuclear level density (NLD) models were tested, and their results were compared with the present findings. Realistic NLDs were also obtained through the spectral distribution method (SDM). The cross-section results, along with the absolute errors, were obtained by investigating the uncertainty propagation and using the covariance technique. Corrections for γ-ray true coincidence summing, low-energy background neutrons, and γ-ray self attenuation were performed. The experimental cross-section obtained in the present study is consistent with previously published experimental data, evaluated libraries, and theoretical calculations carried out using the TALYS code.

Investigation of (γ, xpxn)-reactions on titanium, lutetium, nickel and chromium nuclei at Ebr=37 MeV

For the first time, both the flux-weighted average yields of the 50Cr(γ,pn+2n)48V, natTi(γ,pxn)46Sc, 48Ti(γ,p)47Sc reactions and the isomeric yield ratios of the 175Lu(γ,n)174Lum,g reaction were measured at a bremsstrahlung end-point energy of 37 MeV. The flux-weighted average yields of the 52Сr(γ,n)51Cr, 58Ni(γ,n)57Ni and 58Ni(γ,p)57Co reactions were also measured and their values coincided with the results of the works of the other authors. According to the results of modeling within the framework of the TALYS-1.96 code, a significant contribution of non-statistical processes is ascertained to the mechanisms of the 48Ti(γ,p)47Sc and 50Cr(γ,pn+2n)48V reactions.

63Cu(n, α)60Co cross sections in the MeV region

Cross sections of the 63Cu(n, α)60Co reaction in the MeV neutron energy region were measured using both the direct measurement method and the activation method. A twin-gridded ionization chamber was used for the direct measurement while the high-purity germanium detector was used for the activation method. The measured cross sections using the two methods are consistent within measurement uncertainties. The present results support the evaluation data in the ENDF/B-VII.1 library instead of the latest evaluation data in the ENDF/B-VIII.0 library, which is helpful to clarify discrepancies in measurement and evaluation data. TALYS-1.9 code analysis was performed which shows that the measurement cross sections can be well reproduced with minor adjustments of the input parameters. Through the calculation, it is found that the compound mechanism predominates the 63Cu(n, α)60Co reaction with ratios higher than 0.7 for neutron energy less than 20 MeV.

Study of 239Pu(n,f) prompt fission neutron spectrum

The experimental data concerning 239Pu prompt fission neutron spectrum above 10 MeV are sparse, and no spectrum averaged cross section has been measured in this neutron field yet. The first measurement was performed at the IBR-2 reactor, which uses plutonium dioxide fuel. The present work aimed at the measurement of spectral averaged cross sections for high threshold reactions such as 46Ti(n,p)46Sc, 54Fe(n,p)54Mn, 58Ni(n,X)57Co, 89Y(n,2n)88Y, and 209Bi(n,3n)207Bi to explore the high energy region of the 239Pu prompt fission neutron spectrum. Measurement of spectrum averaged cross section for the 89Y(n,2n)88Y reaction is included in NEA high priority request list. The 58Ni(n,p)58Co reaction was employed as a monitor reaction. The experimental spectral averaged cross sections were derived from reaction rates measured by means of high purity Germanium spectrometry. The experimental values were compared with spectrum averaged cross sections compiled from either ENDF/B-VIII.0, GMA or JEFF-3.3 239Pu prompt fission neutron spectrum and IRDFF-II cross sections. The best agreement, i.e. within uncertainties, was achieved using GMA 239Pu prompt fission neutron spectrum for all reactions under study. Calculation results using JEFF-3.3 and ENDF/B-VIII.0 evaluations of the 239Pu prompt fission neutron spectrum agree well with the experimental data except for the high energy region reflected in the disagreement with the 209Bi(n,3n)207Bi reaction.

A technique for studying (n,p) reactions of astrophysical interest using radioactive beams with SECAR

The formation of nuclei in slightly proton-rich regions of the neutrino-driven wind of core-collapse supernovae could be attributed to the neutrino-p process (νp-process). As it proceeds via a sequence of (p,γ) and (n,p) reactions, it may produce elements in the range of Ni and Sn, considering adequate conditions. Recent studies identify a number of decisive (n,p) reactions that control the efficiency of the νp-process. The study of one such (n,p) reaction via the measurement of the reverse (p,n) in inverse kinematics was performed with SECAR at NSCL/FRIB. Proton-induced reaction measurements, especially at the mass region of interest, are notably difficult since the recoils have nearly identical masses as the unreacted projectiles. Such measurements are feasible with the adequate separation level achieved with SECAR, and the in-coincidence neutron detection. Adjustments of the SECAR system for the first (p,n) reaction measurement included the development of new ion beam optics, and the installation of the neutron detection system. The aforementioned developments along with a discussion on the preliminary results of the p(58Fe,n)58Co reaction measurement are presented.

First (p,n) reaction measurement in inverse kinematics with SECAR

Nucleosynthesis in the νp-process occurs in regions of slightly proton-rich nuclei in the neutrino-driven wind of core-collapse supernovae. The process proceeds via a sequence of (p,γ) and (n,p) reactions, and depending on the conditions, may produce elements between Ni and Sn. Recent studies show that a few key (n,p) reactions regulate the efficiency of the neutrino-p process (νp-process). We performed a study of one of such (n,p) reactions via the measurement of the reverse (p,n) in inverse kinematics with SECAR at NSCL/FRIB.Such proton-induced reaction measurements are particularly challenging, as the recoils and the unreacted projectiles have nearly identical masses. An appropriate separation level can be achieved with SECAR, and along with the incoincidence detection of neutrons these measurements become attainable. The preparation of the SECAR system for accommodating its first (p,n) reaction measurement, including the development of alternative ion beam optics, and the setup of the in-coincidence neutron detection, along with discussion on preliminary results from the p(58Fe,n)58Co reaction measurement are presented and discussed.

Measurement of nuclide production cross sections for proton-induced reactions on [formula omitted]Ni and [formula omitted]Zr at 0.4, 1.3, 2.2, and 3.0 GeV

Nuclide production cross sections for proton-induced reactions on natNi and natZr at incident energies of 0.4, 1.3, 2.2, and 3.0 GeV were measured by the activation method at Japan Proton Accelerator Research Complex (J-PARC). In total, 24 and 43 residual nuclides were measured for the natNi and natZr targets, respectively. Among them, the cross sections of the following reactions were measured for the first time: natZr(p,x)28Mg, natZr(p,x)42K, natZr(p,x)43K, natZr(p,x)44gSc, natZr(p,x)55Co, natZr(p,x)69mZn, and natZr(p,x)93Y reactions. To examine the prediction capabilities, the measured data were compared with the spallation reaction models in PHITS (INCL4.6, Bertini, and JAM as intranuclear cascade models, and GEM as an evaporation model), INCL++/ABLA07, semi-empirical calculation code SPACS, and the JENDL/HE-2007 library. From the evaluation introducing the mean square deviation factor, the best reproducibility was exhibited by the JENDL/HE-2007 library for natNi and INCL++/ABLA07 for natZr.

Measurement of the [formula omitted] reaction cross section induced by 14.8 MeV neutrons

The measurement of the 59Co(n,2n)58Co reaction cross section with the neutron energy of 14.8 MeV has been performed by the activation method and relative measurement principle. The 300 kV Cockcroft Walton Accelerator of China Institute of Atomic Energy was used to produce quasi monoenergetic neutron beams by the T(D, n)4He reaction. Two thin 27Al and 93Nb foils were attached to the 59Co target and performed as monitors. After the irradiation, the HPGe detector and the GammaVision software were used to measure the activity of the irradiated samples and record the counts of γ-rays, respectively. Finally, some relevant physical quantities were corrected after comparing the results with experimental data in the EXFOR database and evaluated data in the ENDF database.

An overview of activation cross-section measurements of some neutron and charged-particle induced reactions in Bangladesh

Abstract Over the last several decades, our research group has been working on nuclear data measurements using a J-25 Neutron Generator, a TRIGA Mark II Research Reactor and a Tandem Accelerator at Savar, as well as an Am/Be neutron source at Rajshahi. The spectrum of fast neutrons having energies from 0.5 to 20 MeV in the core of the TRIGA reactor as well as from 1.5 to 11 MeV of the Am/Be source was well characterized for validation of evaluated data of neutron threshold reactions. Spectrum-averaged cross sections were determined by integral measurements. The integral values measured at both the reactor and the Am/Be source were compared with the integrated data deduced from measured and evaluated excitation functions of some nuclear reactions given in some data libraries. As example, the details on the integral and integrated cross sections of the 64Zn(n,p)64Cu and 60Ni(n,p)60Co reactions are discussed. In both cases, integral test shows that further improvement of the evaluated excitation function reported in data libraries is needed. The use of a newly developed facility at the 3 MV Tandem Accelerator in measurement of proton induced reaction cross sections in the energy region below 5 MeV is outlined, and new results on the 64Ni(p,n)64Cu and natNi(p,x)61Cu processes below 3 MeV are discussed.

Implementation of a Geant4-based code using low-energy gamma-nuclear final state model for photonuclear studies

In this work, we developed a Geant4-based code, IS-2020, for photonuclear studies below 200 MeV covering the giant dipole resonance region (GDR). It uses G4LowEGammaNuclearModel, which consists of preequilibrium and equilibrium reaction mechanisms, for sampling the final states of photonuclear reactions. Simulations for photonuclear reactions on 96Mo, 90Zr, and the strongly-deformed nucleus 153Eu targets have been performed for its validation. Moreover, a good agreement was also observed between experimental relative yields and the simulation results of 59Co(γ,2n)57Co and 50Cr(γ,2n)48Cr reactions induced by bremsstrahlung. The implemented code will be a useful and reliable tool for photonuclear studies, including designing the experimental setup, estimating the yield of outgoing products, and interpreting the measured data.

Excitation function of proton induced reactions on iron in the energy range 85–100 MeV

Excitation functions of the natFe (p, x) 52,54Mn, 55Co, 51Cr, 52Fe, and 46Sc reactions were measured at the proton energy of 87, 94 and 100 MeV, using the stacked foil activation technique followed by the off-line γ-ray spectrometry. The experiment was carried out on the separated sector cyclotron at the Institute of Modern Physics, Chinese Academy of Sciences. The natNi (p, x)57Ni and natAl (p, x)22Na reactions with known cross sections was used to monitor the proton beam intensity. The results from this work were compared with the existing literature data available in EXFOR data library and were found to be in good agreement. TALYS-1.95 is able to reproduce, in most cases, the experimental trend. Our experimental results were also compared with evaluated nuclear data from the ENDF/B-VIII.0, JENDL-4.0/HE, and PADF-2007 libraries as a function of proton energy, which reproduced the trend of the excitation functions of the experimental natFe (p, x) reaction cross-sections. These data expand our knowledge on the related excitation functions to confirm the existing trends and to give additional experimental values on a wider energy range.

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.

Measurement of very high threshold reactions using 252Cf source

Only neutron spectrum standard is 252Cf spontaneous fission neutron spectrum. However, the high energy tail of this spectrum is loaded with high uncertainty. To reduce this uncertainty, it is crucial to use validated cross sections with low uncertainty. The explored set of reactions covers 58Ni(n,X)57Co, 169Tm(n,3n)167Tm, 197Au(n,3n)195Au, 209Bi(n,3n)207Bi and 209Bi(n,4n)206Bi threshold reactions. Measurement of dosimetric 169Tm(n,3n)167Tm, 209Bi(n,3n)207Bi and 209Bi(n,4n)206Bi reactions spectral averaged cross sections (SACS) is included in NEA's High Priority Nuclear Data Request List. All these reactions SACS were measured for the first time. All SACS were derived from experimentally determined reaction rates by gamma spectrometry using the same high-purity germanium detector. In the case of 169Tm(n,3n)167Tm reaction, the difference between experimental and calculated value using the IRDFF-II library is only 1.45%. Concerning 197Au(n,3n)195Au reaction, the reasonable agreement is achieved only using the TENDL-2017 library. In the case of 209Bi(n,3n)207Bi reaction, agreement within uncertainty is not achieved with any library unlike 209Bi(n,4n)206Bi reaction where the agreement within uncertainty is achieved with IRDFF-II library. The best agreement for 58Ni(n,X)57Co reaction is achieved using ENDF/B-VIII library.

Constraining high energy tail of 235U(nth,f) prompt fission neutron spectrum

There is a lack of reliable experiments aiming at the prompt fission neutron spectrum of 235U for energies higher than 10 MeV. The presented experiment performed at the LVR-15 light water reactor aimed at the measurement of very high threshold reactions spectral averaged cross sections such as 55Mn (n,2n)54Mn, 197Au (n,2n)196Au, 197Au (n,3n)195Au, 209Bi(n,3n)207Bi, 209Bi(n,4n)206Bi. 209Bi(n,3n)207Bi and 209Bi(n,4n)206Bi reactions were measured for the first time. 58Ni(n,p)58Co reaction was used as a monitor reaction. The experimental spectral averaged cross sections are derived from reaction rates measured by means of high purity Germanium spectroscopy at the well defined detector. The experimental spectral averaged cross sections are compared with calculations using either ENDF/B-VIII.0 or JEFF-3.3 235U prompt fission neutron spectrum and IRDFF-II cross sections. The discrepancy is higher with higher mean response energy for JEFF-3.3 unlike ENDF/B-VIII.0, where the agreement is good within broad range of mean response energy. Moreover, due to the high thermal neutron flux in the reactor, the experimental reaction rate is compared with calculated 198Au (n,g)199Au reaction rate. The difference of −55.3% for double capture reaction was found in comparison with ROSFOND-2010 calculations.

Excitation functions of 58Ni(n, charged particle) from threshold to 20 MeV using NLD models

58Ni(n, p)58Co, 58Ni(n, 2p)57Fe, 58Ni(n, d)57Co, 58Ni(n, t)56Co and 58Ni(n, α)55Fe reactions are studied using different NLD models from threshold to 20 MeV. Five phenomenological and two microscopic NLD are employed using TALYS 1.9 and EMPIRE 3.2.2 nuclear reaction codes for theoretical calculations. Experimental data taken from EXFOR data library were compared with these. Statistical factors H, R and D have been used to identify the best fitted model. Level density parameters have also been adjusted for further fine-tuning with experimental data. CTFG model is appeared to be a good theoretical fabricator for the neutron-induced 58Ni reaction with newly adjusted level density parameters.

Measurement of natNi(γ, xn)57,56Ni and natNi(γ, pxn)58−55Co reaction cross sections in bremsstrahlung with end-point energies of 65 and 75 MeV

The cross sections of natNi(γ, xn)57,56Ni and natNi(γ, pxn)58−55Co reactions induced by bremsstrahlung end-point energies of 65 and 75 MeV were measured by using the method of activation along with off-line γ-ray spectrometric technique. The natNi(γ, xn)57,56Ni and natNi(γ, pxn)58−55Co reaction cross sections as a function of photon energy were also calculated by using TALYS 1.9 code. The flux-weighted average values at different end-point energies were obtained from the literature data, as well as from the theoretical values of TALYS and TENDL-2017 data library based on mono-energetic photons. Those were compared with the experimental data of present work and found to be in general agreement. It was also found that the experimental and theoretical cross-sections data increase with bremsstrahlung energy up to a certain value. After that the individual reaction cross sections slightly decrease with the increase of bremsstrahlung energy due to the opening of other reactions. As an example, the natNi(γ, xn)57Ni reaction cross section decreases when the natNi(γ, xn)56Ni reaction opens up. Similarly, the natNi(γ, pxn)58Co reaction cross section decreases when natNi(γ, pxn)57Co reaction opens up and so on. These observations indicate the role of excitation energy and its portion in different reaction channels.

58Ni(n,p)58Co and 58Ni(n,2n)57Ni reactions at the neutron energy of 14.54 MeV with covariance analysis

The 58 Ni(n,p) 58 Co and 58 Ni(n,2n) 57 Ni reactions cross sections have been estimated relative to 197 Au(n,2n) 196 Au monitor reaction at the incident neutron energy of 14.54±0.0024 MeV from the D-T fusion nuclear reaction using Purnima neutron generator carried through methods of activation and off-line γ-ray spectrometry. The uncertainty propagation and correlation for measured cross sections have been estimated using covariance analysis through considering the partial uncertainties in different attributes. The present measured reaction cross sections data have been analyzed by comparing with the literature data, with various libraries of evaluated data, like ENDF/B-VIII.0, JEFF-3.3, JENDL/AD-2017, ROSFOND-2010 and TALYS-1.9 theoretical calculations.

Qualitative Analysis of Long-Lived Residual Radioisotopes in 18 MeV Proton Bombarded Enriched Water Target

Residual radioisotope analysis as a result of cyclotron-based 18F production is of paramount importance since it relates to the radiation safety of patients as well as radiation workers. In this investigation, 18-MeV proton beams were employed to irradiate enriched water (H2 18O) target for 18F production while Talys Evaluated Nuclear Data Library (TENDL) 2017 were used to study the origins of the radionuclide impurities. Gamma rays emmitted by the residual radionuclides were detected using a gamma ray spectroscopic system following a month of decay while their origins were analyzed from the TENDL 2017 nuclear cross-section calculations. Experimental results indicated that several long-lived radionuclides such as 109Cd, 57Co, 57Ni, 58Co and 56Co were recorded by the gamma ray spectroscopic system. The long-lived residual radionuclides were presumably due to proton interactions with Havar window and Silver body. Using the TENDL 2017-calculated nuclear cross-sections, it was discovered that several nuclear reactions responsible for the residual radioisotopes include 109Ag(p,n)109Cd which corresponded to the generation of 109Cd radioisotope, 60Ni(p,α)57Co and 58Ni(p,2p)57Co reactions for the formation of 57Co, 58Ni(p,d)57Ni reaction for the production of 57Ni radioisotope, 58Fe(p,n)58Co reaction for the generation of 58Co, and 56Fe(p,n)56Co reaction for the formation of 56Co. This experimental result can be used as a reference for future production of 18F and other radioisotopes should Havar window and silver body are used in the target system.

Investigation of nuclear reaction mechanisms of Nickel isotopes at various energies induced by alpha particles

The excitation functions of 58Ni (α, n + 2p + α) 55Fe, 58Ni (α, n + 3p) 58Co, 58 Ni (α, n + p) 60Cu, 58Ni (α, n + p+α) 56Co, 58Ni (α, p) 61Cu, 58Ni (α, p+α) 57Co and58Ni (α, 2n+p + α )55Co reactions were studied for particle energies up to 70 MeV. The aim of this study is to investigate the reaction mechanisms of 58Ni isotopes induced by alpha particle using computer code COMPLET and EXFOR database. Calculated results of the excitation functions are discussed and compared with the experimental data taken from database. Comparisons of theoretical nuclear reaction cross-section calculations give remarkable agreements with the experimental data taken from EXFOR database.