Triton Emission Research Articles

Theoretical analysis of double-differential cross sections of proton, deuteron, and triton emission in the p+Li7 reaction at 14 MeV

Based on the statistical theory of light nucleus reactions (STLN), the description of the complicated emission processes of proton and light composite charged particles are further improved through considering the effects of Coulomb barriers both in incident and different outgoing reaction channels. And the analysis of the reaction channels including the sequential and simultaneous emission processes for $p + ^7$Li reaction is performed in detail. So the partial spectra of all of outgoing particles are also obtained for different reaction processes. The calculated double differential cross sections of total outgoing proton, deuteron and triton at $E_p = 14$ MeV agree well with the available experimental data for different outgoing angles. The ENDF-6 formatted data, which includes all of the reaction cross sections, elastic angular distributions, double differential cross sections of nucleon and light composite charged particles for $p + ^7$Li reaction, are also obtained by PUNF code.

Analysis of nucleon and triton emissions from nucleon- Li7 collisions below 20 MeV

Analysis of nucleon and triton emissions from nucleon- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Li</mml:mi><mml:mprescripts /><mml:none /><mml:mn>7</mml:mn></mml:mmultiscripts></mml:math> collisions below 20 MeV

The cross sections and energy spectra of the particle emission in proton induced reaction on 204,206,207,208Pb and 209Bi

All cross sections of proton induced reactions, angular distributions, energy spectra and double differential cross sections of neutron, proton, deuteron, triton, helium and alpha-particle emissions for p+ 204,206,207,208 Pb, 209 Bi reactions are consistently calculated and analyzed at incident proton energies below 200 MeV. The optical model, the distorted wave Born approximation theory, the unified Hauser-Feshbach and exciton model which includes the improved Iwamoto-Harada model are used. Theoretically calculated results are compared with the existing experimental data.

Theoretical calculations and evaluations of n+23Na reaction

The data for neutron-induced reactions are indispensable in a lot of applications of nuclear science and technologies. All reaction cross sections, angular distributions, energy spectra, and double-differential cross sections of neutron, proton, deuteron, triton, and alpha-particle emissions are consistently calculated and analyzed for n+ $$^{23}$$ Na reactions at incident neutron energies below 200 MeV, based on nuclear theoretical models. The calculated results are compared with the experimental data and the evaluated data in the ENDF/B-VII, JENDL-4.0, and JEFF-3.2 libraries. In most cases, the calculated results describe the corresponding experimental data well. At the resonance energy region, evaluated experimental data are adopted to fit to the resonance structures.

Neutron-induced reaction on 233U

The 233U neutron-induced reaction cross sections, angular distributions, energy spectra and double differential cross sections of neutron, proton, deuteron, triton, helium and alpha-particle emission are obtained using the theoretical models in the energy range of En⩽200MeV. The theoretical results are compared with recent experimental data and the evaluated data from ENDF/B-VII and JENDL-4.

Calculation and Evaluation of Energy Spectra and Double-Differential Cross Sections for p+90Zr Reactions up to 200 MeV

All cross sections, energy spectra, and double-differential cross sections of six outgoing particles (neutron, proton, deuteron, triton, 3He, and alpha particle) for the p+90Zr reaction are consistently calculated and analyzed at incident proton energies below 200 MeV by using nuclear theoretical models. The optical model; distorted wave Born approximation theory; the intranuclear cascade model; the exciton model; Hauser-Feshbach theory and the evaporation model; and, especially, the improved Iwamoto-Harada model of light composite particle (deuteron, triton, 3He, and alpha-particle) emission have been included in the calculation, which is in good agreement with the experimental data.

Application of the Continuum Discretized Coupled Channels Method to Nucleon-induced Reactions on 6,7Li for Energies up to 150 MeV

Nucleon-induced reactions on 6,7Li are analyzed systematically over a wide range of incident energies up to 150 MeV by using three-body continuum discretized coupled channels method (CDCC) capable of treating the breakup of 6,7Li. The diagonal and coupling potentials in the CDCC equation are obtained by folding the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction with transition densities. The normalization factors of the complex effective interaction are determined so as to reproduce experimental data on neutron total and proton reaction cross sections. Triton emission from 7Li breakup channel and p(n)+Li7→t+Li⁎5(He⁎5) channel is analyzed by the sequential decay model and final state interaction model, respectively. In most cases, the calculated results are in good agreement with experimental data except for the nucleon production double differential cross sections (DDX) at relatively low emission energies.

Improved Simulation of the Pre-equilibrium Triton Emission in Nuclear Reactions Induced by Nucleons

A new approach is proposed for the calculation of non-equilibrium triton energy distributions in nuclear reactions induced by nucleons of intermediate energies. It combines models describing the nucleon pick-up, the coalescence and the triton knock-out processes. Emission and absorption rates for excited particles are represented by the pre-equilibrium hybrid model. The model of Sato, Iwamoto, Harada is used to describe the nucleon pick-up and the coalescence of nucleons from exciton configurations starting from (2p,1h) states. The contribution of the direct nucleon pick-up is described phenomenologically. Multiple pre-equilibrium emission of tritons is accounted for. The calculated triton energy distributions are compared with available experimental data.

Calculations of double-differential triton emission cross sections at 62-MeV proton-induced reactions

Double-differential cross sections (d2σ/dΩdɛ) have been calculated and analyzed for triton production in proton-induced reactions on 27Al, 54,56Fe, 197Au, and 208Pb target nuclei at incident energy of 62 MeV. Calculations of double-differential cross sections have been performed using nuclear models implemented in the TALYS 1.2 code. The calculated results of the double-differential cross sections for triton emission have been compared with the existing experimental data.

Calculations of Double-Differential Triton Emission Cross Sections at 62-MeV Proton-Induced Reactions

Calculations of Double-Differential Triton Emission Cross Sections at 62-MeV Proton-Induced Reactions

Electromagnetic Dissociation Cross Sections Using Weisskopf-Ewing Theory

It is important that accurate estimates of crew exposure to radiation are obtained for future long-term space missions. Presently, several space radiation transport codes, all of which take as input particle interaction cross sections that describe the nuclear interactions between the particles and the shielding material, exist to predict the radiation environment. The space radiation transport code HZETRN uses the nuclear fragmentation model NUCFRG2 to calculate electromagnetic dissociation (EMD) cross sections. Currently, NUCFRG2 employs energy-independent branching ratios to calculate these cross sections. Using Weisskopf-Ewing (WE) theory to calculate branching ratios for compound nucleus reactions, however, is more advantageous than the method currently employed in NUCFRG2. The WE theory can calculate not only neutron and proton emission, as in the energy-independent branching ratio formalism used in NUCFRG2, but also deuteron, triton, helion, and alpha-particle emission. These particles can contribute significantly to total exposure estimates. In this work, photonuclear cross sections are calculated using WE theory and the energy-independent branching ratios used in NUCFRG2 and then compared to experimental data. It is found that the WE theory gives comparable but mainly better agreement with data than the energy-independent branching ratio. Furthermore, EMD cross sections for single neutron removal are calculated using WE theory and an energy-independent branching ratio used in NUCFRG2 and compared to experimental data.

Ternary particle emission in spontaneous fission of 250Cf and 252Cf and in neutron induced fission of 249Cf and 251Cf

The emission probabilities and the energy distributions of tritons, α and 6He particles emitted in the spontaneous ternary fission (zero excitation energy) of 250Cf and 252Cf and in the cold neutron induced fission (excitation energy ≈ 6.5 MeV ) of 249Cf and 251Cf are determined. The particle identification was done with suited Δ E – E telescope detectors, at the IRMM (Geel, Belgium) for the spontaneous fission and at the ILL (Grenoble, France) for the neutron induced fission measurements. Hence particle emission characteristics of the fissioning systems 250Cf and 252Cf are obtained at zero and at about 6.5 MeV excitation energies. While the triton emission probability is hardly influenced by the excitation energy, the 4He and 6He emission probability in spontaneous fission is higher than for neutron induced fission. This can be explained by the strong influence of the cluster preformation probability on the ternary particle emission probability.

The Equilibrium and Pre-equilibrium Triton Emission Spectra of Some Target Nuclei for (n,xt) Reactions up to 45 MeV Energy

Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, working out the systematics of (n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, (n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

Triton Emission Spectra in Some Target Nuclei Irradiated by Ultra-Fast Neutrons

High-current proton accelerator technologies make use of spallation neutrons produced in (p,xn) and (n,xn) nuclear reactions on high-Z targets. The produced neutrons are moderated by heavy water. These moderated neutrons are subsequently captured on 3He to produce tritium via the (n,p) reaction. Tritium self-sufficiency must be maintained for a commercial power plant. So, working out the systematics of (n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, triton emission spectra by using ultra-fast neutrons (incident neutron energy >50 MeV), the (n,xt) reactions for some target nuclei as 16O, 27Al, 56Fe, 59Co, 208Pb and 209Bi have been investigated. In the calculations, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

Double-Differential Cross Sections of the Particle Emission in Neutron-Induced Reactions on 209Bi

All cross sections of neutron-induced reactions, including energy spectra and double-differential cross sections for neutron, proton, deuteron, triton, helium, and alpha-particle emissions, are consistently calculated for the 209Bi nucleus at incident neutron energies below 200 MeV. The results are compared with existing experimental data.

Measurement of the parity-violating asymmetry in the reactions of cold polarized neutrons and light nuclei 6Li, 10B

We present two measurements of parity-violating secondary particle emission asymmetry in the reactions of polarized cold neutrons and light nuclei. We aim at studies of the neutral weak currents in nucleon-nucleon interaction. First, we describe the triton emission asymmetry in the L i 6 ( n , α ) H 3 reaction. It is equal to α P − o d d 6 L i = − ( 8.8 ± 2.1 ) ⋅ 10 − 8 . Second, we present the γ-rays emission asymmetry in the nuclear reaction B 10 ( n , α ) L i ∗ 7 → γ → L i 7 ( g . s . ) . The result is α P − o d d 10 B = + ( 0.8 ± 3.9 ) ⋅ 10 − 8 . Using these values, we constrain the weak neutral current constant in framework of the cluster model f π 6 L i ⩽ 1.1 ⋅ 10 − 7 and f π 10 B ⩽ 2.4 ⋅ 10 − 7 (at 90% c.i.). Both these constrains contradict to “the best” DDH value of f π D D H = 4.6 ⋅ 10 − 7 .

Theoretical Calculations and Analysis for the n + 59Co Reaction up to 20 MeV

All cross sections of neutron-induced reactions, angular distributions, double-differential cross sections, and energy spectra for neutron, proton, deuteron, triton, helium, and alpha-particle emissions are consistently calculated and analyzed for 59Co with incident neutron energies below 20 MeV by using nuclear theoretical models, which are the optical model, preequilibrium and equilibrium reaction theories, and the distorted wave Born approximation theory. Theoretical calculated results are compared with existing experimental data and with evaluated data from ENDF/B-VII and JENDL-3.3.

Ternary α and triton emission in the spontaneous fission of 244Cm, 246Cm and 248Cm and in the neutron induced fission of 243Cm, 245Cm and 247Cm

The emission probabilities and the energy distributions of tritons and α particles emitted in the spontaneous ternary fission (zero excitation energy) of 244Cm, 246Cm and 248Cm and in the cold neutron induced fission (excitation energy ≈ 6.5 MeV ) of 243Cm, 245Cm and 247Cm are determined. The particle identification was done with suited Δ E − E telescope detectors, at the IRMM (Geel, Belgium) for the spontaneous fission and at the ILL (Grenoble, France) for the neutron induced fission measurements. Hence particle emission characteristics of the fissioning systems 244Cm, 246Cm and 248Cm are obtained at zero excitation energy and at an excitation energy around 6.5 MeV. Whilst the triton emission probability is hardly influenced by the excitation energy, the 4He emission probability in spontaneous fission is about 20% higher than for neutron induced fission. This could be explained by the influence of the cluster preformation probability on the ternary α emission.

Measurement of the parity-violating triton emission asymmetry in the reactionLi6(n,α)H3with polarized cold neutrons

We describe measurements of the parity-violating ($P\text{\ensuremath{-}}\mathrm{odd}$) triton emission asymmetry coefficient ${a}_{P\text{\ensuremath{-}}\mathrm{odd}}$ in the $^{6}\mathrm{Li}$$(n,\ensuremath{\alpha})$$^{3}\mathrm{H}$ reaction with polarized cold neutrons. Experiments were carried out at the Petersburg Nuclear Physics Institute (Gatchina, Russia) and at the Institut Laue-Langevin (Grenoble, France). We employed an ionisation chamber in a configuration allowing us to suppress the left-right asymmetry well below ${10}^{\ensuremath{-}8}$. An additional test for a false asymmetry due to eventual target impurities (``zero test'') resulted in ${a}_{0\text{\ensuremath{-}}\mathrm{test}}=(0.0\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$. As final result of this series of experiments we obtained ${a}_{P\text{\ensuremath{-}}\mathrm{odd}}=(\ensuremath{-}8.8\ifmmode\pm\else\textpm\fi{}2.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$.

Calculation and Analysis of n + 180,182,183,184,186,natW Reactions in the En ≤ 250 MeV Energy Range

According to the experimental data of total, nonelastic scattering cross sections and elastic scattering angular distributions of tungsten and its isotopes, a set of neutron optical model potential parameters is obtained. All of the reaction cross sections, angular distributions, energy spectra, γ-ray production cross sections, γ-ray production energy spectra, and the double-differential cross section for neutron, proton, deuteron, triton, helium, and alpha emission are calculated and analyzed for n + 180,182,183,184,186,natW at incident neutron energies from 0.1 to 250 MeV based on the nuclear model theory, which combines the optical model, the unified Hauser-Feshbach theory and exciton model, and the coupled channel theory. Theoretical calculations are compared with existing experimental data and other evaluated data from ENDF/B6.8 and JENDL-3.3.