4He Reaction Research Articles

Differential cross section measurements of the 7Li(3He, p0)9Be, 7Li(3He, p2)9Be, and 7Li(3He, d0)8Be reactions from 2 to 4 MeV

The use of lithium in plasma facing components (PFCs) for fusion reactors is increasingly more prominent due to its ability to enhance plasma performance and potential to protect the underlying high-Z PFCs. In order to use nuclear reaction analysis (NRA) to investigate lithium depth profiles in fusion relevant experiments such as hydrogen retention in lithiated PFCs, there is a need for experimental measurements of the cross section of the reactions of interest over a wide range of energies and in a scattering angle in which the differential cross sections of other relevant species, such as deuterium and oxygen, have been measured. In this paper we report the differential cross sections of the 7Li(3He, p0)9Be, 7Li(3He, p2)9Be, and 7Li(3He, d0)8Be reactions from 2 to 3.919 MeV at a measurement angle of 135°. The measurements were performed on a lithium fluoride film target with the 7Li areal density determined using the 7Li(p, α)4He reaction at 2 MeV and 150°.

Determination of electron screening potential of 6Li(p, [formula omitted])3He reaction using Multi Layer Perceptron based neural network

Understanding nuclear reactions between light-charged nuclei in the sub-Coulomb energy region is crucial for several astrophysical processes. Accurate determination of the reaction cross-section within the astrophysically important Gamow range is challenging due to electron screening. Various methods, including polynomial fits, R-Matrix, and the indirect Trojan Horse Method (THM), have estimated electron screening energies that exceed the adiabatic limit. This study aims to derive the bare astrophysical S-factor for the reaction 6Li(p,α)3He and to extract electron screening energies using Multi-Layer Perceptron-based Artificial Neural Network (ANN) analysis. Experimental S-factors for 6Li(p,α)3He, obtained from the literature, are reanalyzed with the ANN algorithm to determine the energy-dependent S-factor. The bare astrophysical S-factor is calculated from data above 60 keV, where electron screening is negligible. The electron screening potential is then derived by comparing the shielded S-factor with the bare S-factor. The ANN-based analysis yields an electron screening potential of 220 eV, suggesting that ANN could be a viable tool for estimating electron screening potentials in light nuclei reactions.

Measurements of the 128Te(n, 2n)127m,gTe reaction cross sections and isomeric cross section ratio of 127m,gTe at the neutron energy of 14 MeV* *Supported by the National Natural Science Foundation of China (12165006, 12375295)

In this study, measurements of the 128Te(n, 2n)127m,gTe reaction cross sections and the computation of the isomeric cross section ratio were performed around the neutron energy of 13−15 MeV. We used a γ-ray spectrometric technique to conduct the measurements. The neutron energy was produced by the 3H(d,n)4He reaction. For the 128Te(n, 2n)127m,gTe reaction, the excited state, ground state, total cross section, and isomeric cross section ratio were determined using the TALYS-1.96 code, a theoretical nuclear model that allows for variations in density options. The initial experimental data, assessed nuclear data, and theoretical calculations based on the TALYS-1.96 algorithm were compared with the measurement results. The new data produced by this study are essential for validating nuclear models and establishing parameters for nuclear reactions.

Measurement of cross-section of the 6Li(d,α)4He, 6Li(d,p)7Li, 6Li(d,p)7Li*, 7Li(d,α)5He, and 7Li(d,nα)4He reactions at the deuteron energies from 0.3 MeV to 2.2 MeV

The interaction of a deuteron beam with lithium is characterized by a high yield of neutrons, high energy of neutrons and a large variety of reactions. The reliable data of the reactions cross-sections are important for many applications, including radiation testing of advanced materials and equipment. The experimental data on the cross-sections differ greatly from one author to another; for a number of reactions there is no data on the cross-section in the databases. Measurements of the reactions cross-sections were carried out at the accelerator-based neutron source VITA at Budker Institute of Nuclear Physics (Novosibirsk, Russia) using an α-spectrometer. The 6Li(d,α)4He, 6Li(d,p)7Li, 6Li(d,p)7Li*, 7Li(d,α)5He, and 7Li(d,nα)4He reactions cross-sections at deuteron energies from 0.3 MeV to 2.2 MeV have been measured. The obtained data are presented tabular form.

Compact Monoenergetic Proton Generator in MeV Region Using NANOGAN

For simple applications, such as the calibration of a charged particle detector, a multi-MeV proton generator may be preferable to cyclotrons or electrostatic accelerators such as Van de Graaff. Thus, a compact proton generating system, consisting of 10Ghz ECR ion source NANOGAN and a deuteron target, was developed at the Research Center for Nuclear Physics at Osaka University. A 3He2+ beam was generated by the NANOGAN with the acceleration voltage of 20∼45 kV in an experiment that utilized the fusion reaction 3He + deuteron (d) → proton(p) + 4He. The monochromatic protons with energies of 14.67 MeV were successfully obtained at the atmosphere side of the target in the experimental setup, when a novel target base with a thin metal foil and Polyimide film window are used.

The measurement of the 6Li(n, t)4He reaction cross-section in the energy range of 4.25–7.50 MeV

The measurement of the 6Li(n, t)4He reaction cross-section in the energy range of 4.25–7.50 MeV

Fast-ion orbit origin of neutron emission spectroscopy measurements in the JET DT campaign

In the JET DTE2 deuterium-tritium campaign, neutron diagnostics were employed to measure 14 MeV neutrons originating from D(T,n)4He reactions. In discharge 99965, a diamond matrix detector (KM14) and a magnetic proton recoil (MPRu) detector with a vertical and an oblique line-of-sight were used, respectively. At the timepoints of interest, a significant decrease in the expected diagnostic signals can be observed as electromagnetic wave heating in the ion cyclotron range of frequencies (ICRF) is switched off. Utilizing only TRANSP simulation data, the fast-ion distribution is found to have been likely composed mostly of trapped orbits. In contrast, analysis performed using orbit weight functions revealed that the majority of neutrons in the KM14 Ed=9.3 MeV and MPRu Xcm=33 cm measurement bins are to have originated from fast deuterium ions on co-passing orbits. This work explains the perhaps surprising results and shows that the relative signal decrease as ICRF heating is switched off is largest for counter-passing orbits. Finally, for the magnetic equilibria of interest, it is shown how stagnation orbits, corresponding to ∼1 % of the fast-ion distribution, were completely unobservable by the KM14 diagnostic.

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.

Determination of Tritium-Helium-3 differential cross-section in the energy range between 0.6 MeV and 3.3 MeV for tritium depth profiling in solids

The differential cross-section for the 3He+3H nuclear reaction was measured in a thin tritiated PdTi film that was deposited on a Si wafer. The sample was loaded with 3H2 gas at a temperature of 300 °C and at a pressure of 1.8 bar. The total activity of the sample, measured by the liquid scintillation technique, was found to be 395 MBq. Two peaks were observed in the spectrum of the thick Si detector, corresponding to the 3H(3He,d)4He and 3H(3He,p)5He reaction channels. The differential cross-section was determined for the energy range of the 3He beam from 0.6 to 3.4 MeV, at three scattering angles of 125, 135 and 155°. The differential cross-section for the first channel remained almost constant within the measured energy range, while the cross-section for the second channel increased with energy. In both cases, the cross-sections reached their maximum value at the lowest scattering angle measured. The differential cross-sections were verified using a thick solid tritiated tungsten target. For assessing the tritium depth profile, only the reaction channel 3H(3He,d)4He can be utilized.

Experimental study of 6He Coulomb breakup as an indirect measurement of 4He(2n,γ)6He reaction rate for the astrophysical r-process

In this work, we report the measurement of elastic and Coulomb break-up channels in 6He+208Pb collisions at Elab = 19.3 MeV, close to the Coulomb barrier of this system ∼ 19 MeV. In the context of the astrophysical r-process, the reaction 4He(2n,γ)6He has been proposed to be a key reaction in the path of synthesizing seed nuclei for the r-process, as 12C, in an environment composed mainly of alpha particles and neutrons. Based on a theoretical approach for treating three body reactions by means of which its reaction rate can be inferred, our experimental approach aims to obtain an indirect measurement of the reaction rate of 4He(2n,γ)6He by measuring the Coulomb breakup of 6He under the intense electric field produced by a 208Pb target nucleus. The experiment was carried out at the TriSol facility operated in the Nuclear Science Laboratory of the University of Notre Dame, USA, which delivered a 6He beam together with other contaminants. Particular care must be taken for the alpha particles produced in the production reaction.

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.

Continuous and pulsed fast neutron beams at the CNA HiSPANoS facility

The characteristics of the fast neutron beams produced in the HiSPANoS facility at Centro Nacional de Aceleradores (CNA) are presented. The neutrons are generated by deuteron beams from a 3 MV tandem accelerator in either continuous (5 μA) or pulsed (2 ns width, 500 kHz and 4% duty cycle) mode. In this work, the pulsed mode was used in a time-of-flight characterization of the produced neutron beams in terms of yield, flux, energy resolution, and background. The results were then validated through their comparison with previously published data.Quasi-monoenergetic neutron beams between 2 and 6 MeV are produced by means of the 2H(d,n)3He reaction, featuring a neutron yield of 106 n/sr/μC at the target, with an energy resolution of about 7% at 150 cm. Neutron beams with broad energy distributions are produced by deuteron irradiation of thick beryllium and lithium targets, resulting in maximum neutron energies of 10 and 20 MeV, respectively. In this case, the neutron yields are significantly higher, reaching 1010 n/sr/μC.On the basis of these results, we consider that the HiSPANoS facility is now fully operational for the usage of fast neutrons by internal and external users of CNA.

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.

On the accuracy of cross-section measurements of neutron-induced reactions using the activation technique with natural targets: The case of Ge at E[formula omitted] MeV

Several cross-section measurements of neutron-induced reactions on Ge found in literature, are performed utilizing natGe targets. The production of the same residual nucleus as the measured one might occur as a result of the unavoidable presence of neighboring isotopes in the same target, acting as a contamination. Corrections must be made based on theoretical calculations and models in order to resolve this problem. The accuracy and limits of a methodology for these “theoretical corrections” are investigated in this work using isotopically enriched targets, which can produce very accurate results without the need for such corrections. Experimental cross-section measurements have been made for the 76Ge(n,2n)75Ge, 72Ge(n,α)69mZn and 72Ge(n,p)72Ga reactions, via the activation technique, with the 27Al(n,α)24Na reaction used as reference, employing both a natGe and isotopically enriched Ge targets. The 3H(d,n)4He (D–T) reaction was used for producing the quasi-monoenergetic neutron beam in the 5.5 MV Tandem Accelerator Laboratory of the National Centre for Scientific Research “Demokritos” in Athens, Greece, at an incident deuteron beam energy of 2.9 MeV. Using HPGe detectors, γ-ray spectroscopy was applied to determine the induced γ-ray activity of the residual nuclei.

Anti-[formula omitted] transformations and complex non-Hermitian [formula omitted]-symmetric superpartners

We propose a new algebraic formalism for constructing complex non-Hermitian PT-symmetric superpartners by extending a conventional shape-invariant superpotential into the complex domain. The resulting potential is an unbroken super- and parity-time (PT)-symmetric shape-invariant potential with real energy eigenvalues, maintaining this property for all parameter values. In order to restore the probabilistic interpretation within a true quantum theory, a new inner product called the CPT-inner product is defined in PT-symmetric quantum mechanics, replacing the Dirac Hermitian inner product. In this work, we propose a new version of the inner product called the anti-PT (APT)-inner product, 〈A|B〉≡|A〉APT.|B〉, which replaces the previous versions without any additional considerations. This PT-supersymmetric quantum mechanics framework also allows for the unification of various areas of physics, including classical optics and quantum mechanics. To validate the theory, we present exact solutions for optical waveguides and the quantum tunneling probability, demonstrating excellent agreement with experimental data for the probability of crossing the potential barrier in the 3H(d,n)4He reaction.

Reactions induced by 30 MeV 3He beam on 9Be : cluster transfer reactions* *Supported by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (AP14870958)

An experiment was conducted for studying the cluster structure of Be induced by He ions at an energy of 30 MeV. As results of the nuclear reaction 3He + 9Be, the differential cross sections for the exit channels – elastic, inelastic, α + 8Be, 6He + 6Be, 6Li + 6Li, and 7Be + 5He – were measured. Elastic and inelastic scattering data were treated within both the optical model and coupled channel method. A new set of optical potentials was considered for the elastic scattering. The deformation parameter was established for the transition . Cluster transfer reactions were analyzed via the coupled reaction channel method. The nuclear reactions with the exit channels 6He + 6Be, 6Li + 6Li, and 7Be + 5He were complemented by two-step transfer mechanisms. The contribution of each reaction mechanism were shown and compared with the findings of other authors.

Development of A 14.8-MEV Mono-Energetic Neutron Field in Korea Research Institute of Standards and Science.

A standard irradiation field for 14.8-MeV neutrons is under development for mono-energetic neutron standards research in the Korea Research Institute of Standards and Science, Republic of Korea. We developed a target chamber with the associated alpha particle (AAP) system for 14.8-MeV mono-energetic neutrons by a T(d,n)4He reaction. We designed the target chamber and the AAP detector system using a two-body kinematic calculation. We conducted simulations of the T(d,n)4He reaction on a tritiated target to determine a specification of the target and the AAP detector. This paper will discuss the simulation and calculation results for the associated particle system design.

Investigating the Primordial Universe through nuclear physics

Big Bang Nucleosynthesis (BBN) requires several nuclear physics inputs and nuclear reaction rates. An up-to-date compilation of direct cross sections of is given, being these ones among the most uncertain bare-nucleus cross sections. A particular attention is devoted to recently indirectly measured cross-section which give important hints for the nuclear astrophysics community.In reality, a significant experimental effort has been made over the past 10 years to explore reactions important to the BBN and determine their astrophysical S(E)-factor using the Trojan Horse Method (THM). Then, numerical calculations are made in the relevant temperature ranges for BBN (0.01<T9 <10) to determine the reaction rates and the relative error for the four reactions of interest. The effects of these values on the calculated primordial abundances and isotopical composition for H, He, and Li were then assessed by using them as input physics for computations of primordial nucleosynthesis. Additionally, recent findings regarding the 7Be(n,alpha)4He reaction rate were taken into consideration. These were put up against estimates of primordial abundance derived from observation at various astrophysical places. Additionally, perspectives on reactions will be examined.

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.

Features of using Cs2LiYCl6:Ce based scintillation detector for time-of-flight application

A detailed study was made of the systematic uncertainties that arise when a constant fraction method is used for the timing analysis of the signals from a Cs2LiYCl 6:Ce-based detector. It is shown that there is a systematic difference in the rise time of the signals corresponding to the different types of particles. This difference leads to a systematic shift of the timestamp when the constant fraction algorithm is used for timing analysis. The value of the shift of the timestamps between signals corresponding to γ-rays and 6Li(n,t)4He reaction products reaches ∼3.6 ns at neutron energy of 0.6 MeV and ∼2.2 ns for neutron energy of 7.0 MeV. This shift can lead to a significant distortion of the measured results when the position of the prompt γ-rays peak is used to calibrate the time scale of the spectrometer. On the example of some previously obtained results it is shown that the data distortions can be explained by an uncompensated shift in the timestamp.