Calculated Excitation Functions 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.

Investigation of the production routes of 81,82m,83,84 Rb isotopes through proton-induced nuclear reactions on 82,83,84,86 Kr

Investigations using nuclear reaction models are significant and have considerable consequences in terms of understanding nuclear reaction processes and their nature. The nuclear data on radionuclides created by the cyclotron find application in nuclear diagnostics and therapeutic treatments. The excitation function of proton-induced nuclear reactions on 82,83,84,86 Kr for the generation of medically beneficial short-lived radioisotopes 81,82m,83,84 Rb from threshold energy to 50 MeV has been investigated using Koning–Delaroche optical model potential with nuclear level density (NLD) from both the phenomenological and microscopic nuclear models incorporated in TALYS1.96 code. The phenomenological constant temperature + Fermi gas model, back-shifted Fermi gas model, generalised superfluid model, and microscopic NLD from the Skyrme–Hartree–Fock–Bogoliubov, Gogny–Hartree–Fock–Bogoliubov, and temperature-dependent Gogny–Hartree–Fock–Bogoliubov NLD tables have been used to calculate the excitation function. The calculated excitation functions are compared with the experimental data from EXFOR and the TALYS evaluated nuclear data library (TENDL2023). An analysis is carried out by estimating the mean deviation D-value between the theoretical and experimental cross-sections, and the NLD model corresponding to the best result is used for the estimation of activity and production yield for each reaction channel.

Production Cross Sections of Residual Nuclides from 93Zr + p at 27 MeV/Nucleon

Abstract Nuclear transmutation emerges as a promising approach for reprocessing high-level waste, specifically treating long-lived nuclides like 93Zr from spent fuel. It is essential to accumulate reaction data for these nuclei to advance this prominent treatment and to build a comprehensive understanding of reaction mechanisms. In this study, the residual production cross sections resulting from proton-induced reactions on 93Zr were measured at 27 MeV/nucleon in inverse kinematics. At the RI Beam Factory (RIBF) the OEDO beamline was used to deduce production cross sections for isotopes, 91 − 93Nb, 91, 92Zr, and 88, 89Y. Comparing the results from this study and prior research with calculated excitation functions, a moderate agreement is found with theoretical predictions derived from TALYS and CCONE. The measured cross sections offer valuable insights for future considerations in nuclear-waste treatment facilities. This is particularly relevant for facilities exploring innovative methods, such as accelerator-driven systems.

Coupled channels analysis of 8He+4He scattering and resonant behaviour

Previously measured elastic scattering and two-neutron transfer angular distributions for 8He scattered from a 4He target [Phys Lett. B 75, 58-62, 2017] are analysed using the coupled reaction channels (CRC) formalism and the effect of 1, 2 and 4-neutron transfers on both the elastic scattering and 6He + 6He channels is examined. The CRC calculations find that 1n and 2n transfers are the dominant processes in the production of 6He while the influence on the elastic scattering of 4n transfer between the 4He cores is small. Calculated excitation functions based on fits to both data sets suggest resonant-like behaviour centred at 12Be excitation energies of about 13 MeV and 14-16 MeV, both associated with the L=2 and 4 partial waves and consistent with molecular structures in the intermediate 12Be system.

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.

An investigation of the effects of optical model potentials and level density models on the calculation of excitation function for the production of medical isotopes $$^{68}Ge$$ and $$^{82}Sr$$ through alpha and proton induced nuclear reactions

An investigation of the effects of optical model potentials and level density models on the calculation of excitation function for the production of medical isotopes $$^{68}Ge$$ and $$^{82}Sr$$ through alpha and proton induced nuclear reactions

A Study of Excitation Functions in the Interaction of 4He + 59Co System at 4-9MeV/Nucleon

The excitation functions for six reactions produced in the interactions of 4He +59Co have been measured in the energy range up to 41MeV using the activation technique. The measured excitation functions are compared with theoretical calculations done using the computer program COMPLET. The effect of the variation of various program parameters on calculated excitation functions have been studied. The study signified that an admixture of equilibrium and pre-equilibrium emissions is required to reproduce the presently calculated excitation functions.An attempt was made to deduce the contribution coming from pre-equilibrium emission. It was found that the pre-equilibrium contribution increases with projectile energy. Further, the threshold of pre-equilibrium emission for different reaction channels is found to be different, depending on the associated Q-value. Furthermore, the present result revealed a strong correlation between pre-equilibrium contribution and particle multiplicity. DOI: 10.7176/APTA/86-01 Publication date: October 31 st 2022

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

Study of the production and decay properties of neutron-deficient nobelium isotopes

The new neutron-deficient isotope \(^{249}\)No was synthesized for the first time in the fusion-evaporation reaction \(^{204}\)Pb(\(^{48}\)Ca,3n)\(^{249}\)No. After separation, using the kinematic separator SHELS, the new isotope was identified with the GABRIELA detection system through genetic correlations with the known daughter and granddaughter nuclei \(^{245}\)Fm and \(^{241}\)Cf. The alpha-decay activity of \(^{249}\)No has an energy of 9129(22) keV and half-life 38.3(2.8) ms. An upper limit of 0.2% was measured for the fission branch of \(^{249}\)No. Based on the present data and recent information on the decay properties of \(^{253}\)Rf and aided by Geant4 simulations, the ground state of \(^{249}\)No is assigned the 5/2\(^+\)[622] neutron configuration and a partial decay scheme from \(^{253}\)Rf to \(^{245}\)Fm could be established. The production cross-section was found to be \(\sigma \)(3n)=0.47(4) nb at a mid-target beam energy of 225.4 MeV, which corresponds to the maximum of the calculated excitation function. Correlations of the \(^{249}\)No alpha activity with subsequent alpha decays of energy 7728(20) keV and half-life \(1.2_{-0.4}^{+1.0}\) min provided a firm measurement of the electron-capture or \(\beta ^{+}\) branch of \(^{245}\)Fm to \(^{245}\)Es. The excitation function for the 1n, 2n and 3n evaporation channels was measured. In the case of the 2n-evaporation channel \(^{250}\)No, a strong variation of the ground state and isomeric state populations as a function of bombarding energy could be evidenced.

New empirical formulae for (n, p) reaction cross sections on stable isotopes from Z= 21 to Z= 51 for energies up to 20 MeV

Neutron Induced reactions on different target nuclei have get impact on many nuclear basic sciences and applications. Due to the lack of literature available experimental data for many targets, empirical formulae for the (n, p) reactions cross section on different targets and different incident neutron energies are formulated. The formulae are used for calculation of excitation functions for target isotopes having atomic numbers in the range from 21 to 51 and neutron energies from 20 MeV down to respective threshold energy of each reaction. The results are compared to the existing experimental results as well as the TENDL-2019 database values.

Production Cross Sections and Induced Activity in Ge Isotopes by 30 MeV Proton Beam

The excitation functions of 70 Ge(p,n) 70 As, 72 Ge(p,n) 72 As, 74 Ge(p,n) 74 As and 76 Ge(p,n) 76 As reactions were studied from reaction threshold to 30 MeV by using EMPIRE-3.2 and TALYS-1.9 nuclear reaction model codes. This study is important because some isotopes produced are important for positron emission tomography (PET). Direct, pre-compound and compound nuclear reactions are considered as main nuclear reaction mechanisms in the codes. The calculated excitation functions have been compared with available experimental data and found to be in fair agreement. Furthermore, the contributions of various reaction mechanisms have been studied in total reaction cross-section that varies with the incident proton energy. The estimation of induced radio activity in thick Ge target due to the primary interaction is carried out for1μA, 30 MeV proton beam.

Measurements of formation cross-sections of short-lived nuclei around the 14 MeV neutron induced reactions on 180Hf and 90Zr and theoretical calculation of excitation functions

The cross sections of the 180Hf(n,p)180Lu and 90Zr(n,2n)89mZr reactions were measured around the neutron energies of 13.5–14.8 MeV by using the activation technique. The excitation functions of the above reactions in the neutron energies from the threshold to 20 MeV were calculated by using the nuclear theoretical model program system Talys-1.9 with the adjusted relevant parameters. The measured results were discussed and compared with previous experiments by other researchers and with the evaluated data of ENDF/B-VIII.0, CENDL-3.1, JEFF-3.3, JENDL-4.0u2, BROND-3.1 as well as the theoretical values based on Talys-1.9. The obtained experimental values at some neutron energies, within experimental error, are consistent with those of the fitting line of the results of previous experiments and are also consistent with those of theoretical excitation curve at the corresponding energies. The obtained theoretical excitation curves match well with most of the experimental data.

Measurements of neutron capture cross-sections for 187Re isotope around 14 MeV neutrons and theoretical calculations of excitation functions

The cross-sections of the 187Re(n,γ)188mRe and 187Re(n,γ)188gRe reactions were measured at the four neutron energies of 13.5, 14.1, 14.4 and 14.8 MeV through the activation method and using off-line γ-ray spectrometry. The previously developed formulas were used to subtract the effects of γ rays with close energies and the contribution from the excited state. A high-resolution γ-ray spectrometer with high-purity germanium detector was used to measure the induced γ activities. The simulation computations of the excitation functions concerning the above-mentioned two nuclear reactions were performed by adopting the nuclear theoretical model program system Talys-1.9. The theoretical excitation curves in the incident neutron energy range from 2.53 × 10−8 to 20 MeV were acquired. The fitting line of our results in the neutron energy range of 13.5–14.8 MeV, within experimental uncertainty, agrees very well with the theoretical excitation curve based on the computer code Talys-1.9.

Coupled channel analysis of fusion excitation function for 9Be+64Zn system at near and above barrier energies

We have calculated excitation functions of incomplete fusion, complete fusion and total fusion processes for [Formula: see text] system at near and above barrier energies. In particular, breakup effects of weakly bound projectile [Formula: see text], which has been considered as a two body system [Formula: see text] with a breakup threshold of 1.667 MeV, have been studied. The calculations are performed by using the code FRESCO, which is based on Continuum Discretized Coupled Channel (CDCC) approach. The present analysis of the total fusion excitation function for the system [Formula: see text] shows that it is suppressed at above barrier energies and enhanced at sub barrier energies when the breakup effects are taken into account. In addition, the comparison of the probabilities of incomplete fusion from neutron capture and that from alpha capture shows the dominance of former over later.

Excitation function calculations in proton-induced nuclear reactions on Zn and Cu upto 80 MeV

Nuclear reaction model codes like the EMPIRE-3.2, the ALICE-1991 and the TALYS-1.9 have been used to calculate the excitation functions of 63Cu(p,n)63Zn, 65Cu(p,n)65Zn, 66Zn(p,n)66Ga, 67Zn(p,n)67Ga, 67Zn(p,2n)66Ga, 68Zn(p,n)68Ga and 68Zn(p,2n)67Ga reactions for incident proton energy range of 1–80 MeV. These codes compute reaction cross section using the direct, the compound and the pre-equilibrium (PEQ) processes as major nuclear reaction mechanisms. The computed results have been analyzed and compared with the available experimentally measured data and with the evaluated nuclear data files. Good agreements have been found between theoretically calculated and measured data.

Newly developed semi-empirical formulas of nuclear excitation functions for (n,α) reactions at the energy range 12 ≤ En ≤ 20 MeV and mass number range 30 ≤ A ≤ 128

A new semi-empirical systematics of (n,α) reaction excitation functions for nuclei with mass number 30≤A≤128 at neutron induced energy range 12≤En≤20 MeV is obtained. It is based on the evaporation model and the pre-equilibrium exciton model. The Droplet model of Myers and Swiatecki was used to express the reaction energy Q. The Dostrovsky formula was introduced to formulate the expression of the inverse cross section channel.The systematics behavior of the different terms of the Droplet model involved in the reaction energy Q(n,α) was verified individually before choosing the relevant terms and setting up the formulae. By fitting these formulae to the existing cross-section data, the adjustable parameters have been determined and the systematics of the (n,α) reaction have been studied. The new semi-empirical formula has been verified for predictions of the excitation functions of nuclear reactions not used in the fitting. The calculated excitation functions were compared to the experimental data and EMPIRE-3.2 code calculations. A good agreement between excitation functions systematics and EXFOR data was observed for great number of (n,α) reactions.

Evaluation of the nuclear excitation functions of fast neutron-induced reactions on 52Cr and 56Fe isotopes

In this article, we present the nuclear excitation functions of the fast neutron-induced reactions 52Cr(n,p)52V, 52Cr(n,α)49Ti, 52Cr(n,2n)51Cr, 56Fe(n,p)56Mn, 56Fe(n,α)53Cr, and 56Fe(n,2n)55Fe, because these measurements are critical to estimate the level of the neutron activation for the fusion reactor structural materials. The theoretical computer codes TALYS-1.8 and EMPIRE-3.2.2 have been used for the calculation of the excitation functions. The theoretical calculations consider different nuclear reaction models, level density models and optical model potentials. The calculated excitation function results are compared with the existing experimental data obtained from the IAEA-EXFOR database, as well as with those available in the TENDL-2017 and ENDF/B-VIII.0-evaluated nuclear data libraries. The obtained results show the variation in excitation functions for different level density models. Moreover, we have studied the contribution from different reaction mechanisms in total reaction cross-section which varies with the incident neutron energy. These excitation function results can be useful to estimate the important parameters of nuclear reactors, such as nuclear heating, nuclear transmutation rates, and waste management etc. This kind of information can enhance the basic understanding of the mechanism of the fast neutron-induced nuclear reactions.

Proton-produced radionuclides for radiodiagnostic modalities in cancer studies

With increasing rates of cancer cases globally, scientists and technologists have proposed cancer diagnosis using radioisotope-labelled chemical compounds. In this paper, using the TALYS 2017 codes we calculated excitation functions of several (p,n), (p,α), (p, 2n) and (p,3n) nuclear reactions. The TALYS-calculated results indicated that a few radionuclides such as 18F, 11C, 64Cu, I24I could be produced at relatively low threshold energies ranging from as low as 2.7 MeV to 4 MeV, whereas other radionuclides such as 123I, 201Tl, 111In and 67Ga could only be generated with protons of over 10 MeV. While 18F, 15O, 64Cu and 124I radionuclides could be produced via (p,n) nuclear reactions, other radionuclides including 99mTc, 123I, 111In and 67Ga could be produced through (p,2n) nuclear reactions . In addition, (p,α) nuclear reaction was found to suit 11C and 13N radionuclide production, whereas (p,3n) fit 201Tl production. In general, most radionuclides used for Single Photon Computed Tomography (SPECT) modality requires higher proton incident energies compared to those for Positron Emission Tomography (PET) modality in nuclear medicine.

Measurements of activation cross sections for proton induced reactions on natural platinum targets leading to the formation of gold radioisotopes

Proton beam of energy 14.7 MeV have been used to study the reaction cross sections and the excitation functions of the possibly produced gold radioisotopes using stacked foil technique. Five Au radioisotopes namely, 193Au, 194Au, 195Au, 196Au and 198Au have been measured and discussed in the energy range from the proton reactions threshold up to 14.7 MeV. Theoretically calculated excitation functions were obtained using EMPIRE 3.2.2 and ALICE-IPPE codes, in addition to TENDL 2017 library. Integral yields were calculated and discussed.

Excitation function of the [formula omitted] reactions in the energy range 10–22 MeV

The excitation functions of the proton induced Anatg reactions were measured using the stack foil activation followed by the off-line γ-ray spectrometry. The present work was carried out at 14UD BARC-TIFR Pelletron accelerator, Mumbai, India. The proton beam of 22 MeV was used for the irradiation of the samples and was degraded along the stack of silver foils. The measured cross-section data were compared with the existing literature data available in EXFOR. The calculated excitation functions were also compared with the calculated values from TALYS-1.9 model code using a suitable input parameters for the pure compound nucleus (CN) and pre-equilibrium (PE) reaction cross-sections. ALICE-2014 code was also used to validate the present experimental findings as well as the TALYS-1.9 results.