Cross Sections of 14 MeV Neutron Induced Reactions on Wolfram Isotopes

Introduction The importance of nuclear data for fusion power reactor design has been acknowledged, in particular for safety, environment reasons and economics. The 14 MeV neutron activation cross sections are the key nuclear data for environmental impact, material recycling, waste handling. Due to the large number of materials and traces of alloy elements and contamination, there are requirements for a complete database covering large number of nuclides. Problems still exist for some reactions, for example, for ~(182)W(n,n′α)~(178m2)Hf reaction only one measurement was published,     

Theoretical Calculation of Neutron Cross Sections for ~(176)Hf

Neutron activation cross sections calculation for ~(176)Hf in the neutron energy below 20 MeV is carried out with UNF code. The calculated cross sections for (n,γ), (n,p), (n,α), (n,d), (n,t), (n,2n) and (n,3n) reaction are given. The results of the calculation are compared with the available experimental data and a good agreement is obtained. The calculation is also compared with the relevant evaluation data.     

Calculation of Neutron Monitor Reaction Cross Sections of ~(90)Zr in Energy Region up to 100 MeV

The activation products ~(89)Zr (half life is 78.41 h) and ~(88)Zr(half life is 83.4 d) can be produced from n ~(90)Zr reaction through (n,2n) and (n,3n) reactions, respectively. ~(88)Y(half life is 106.65 d) can be produced through(n,2np), (n,nd), and(n,t)reactions; ~(87)Y(half life is 79.8 h)through(n,3np), (n,2nd), and(n,nt)reactions; ~(86)Y(half life is 14.74 h) through(n,4np), (n,3nd), and (n,2nt) reactions.     

Evaluation of Neutron Induced Helium Production and Activation Cross Sections for Some Nuclei

The activation characters of chosen fusion materials are important in determining proper reactor technologies. In order to meet these requirements for fusion design studies, not only all activation cross sections for the fusion materials themselves have to be know, but also those for all possible impurities require to be considered if they lead to long-lived activities.     

A Simultaneous Evaluation of Neutron Induced Reaction Cross Sections for ~(56)Fe at E_n=14.1 MeV

A simultaneous evaluation of neutron induced reaction (i. e., (n,total),(n,n), (n,non), (n,n′), (n,2n), (n,nα), (n,np), (n,γ), (n,p), (n,d), (n,α), (n,n-em), (n,p-em), (n,d-em) and (n,α-em) reaction) cross sections on ~(56)Fe at E_n=14.1 MeV is carried out. The evaluated cross sections are compared with the corre-sponding measured values and the evaluations for CENDL-2, ENDF/B-6, JEF-2.2, JENDL-3 and BROND-2.     

The Small Angle Scattering Cross Sections of 14.7 MeV Neutron for ~(238)U

This work is the continuation and the development of the previous researchwork.The main detector is a position sensitive neutron detector whichconsists of a long cylindric liquid scintillation tube and two photomultipliers atboth ends of the tube.The position imformation of the incident neutron isextracted by the time difference between the signals from the two photomultipliers.Recently the measurement have been done on the Cockcroft accelerator in Tsing-hua University.Special attention has been paid to the improvement of the relia-bility and the precision in the measurements.     

Progress on Calculation of Direct Inelastic Scattering Cross Section of Neutron

For n ~(238)U inelastic scattering cross section, there exist discrepancies among the available evaluations in various libraries. This is partly due to the difference of Direct Inelastic Scattering(D.I.S.) cross section calculated with Coupled Channel Optical Model(CCOM). So some research work on this problem has been done in 1995.     

Evaluation of H Total Neutron Cross Section from 20 MeV to 2 GeV

Introduction The nuclear data in intermediate and high energy region have been widely used in various fields for last ten years, such as radioactive waste processing, radio therapy for cancer etc. So the measurements and evaluations of these data become more and more, these require the standard cross section in this energy region, just like already did in low energy region (≤20 MeV). In this work, the H total neutron cross section was evaluated from 20 MeV to 2 GeV, the purpose is to provide a cross section standard.     

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

In this study, double differential deuteron emission cross sections for ²⁷Al, ^54,56Fe, ¹⁹⁷Au, ²⁰⁸Pb and ²⁰⁹Bi target nuclei have been calculated by the TALYS code at 62 MeV proton energy. The use of TALYS involved calculations by the pre-equilibrium exciton model and the Hauser–Feshbach model. The calculated double differential cross sections have been compared with the experimental data taken from the literature.     

Theoretical Analysis of Neutron Double-Differential Cross Section of n＋^14N at 14.2 MeV

By using a new reaction model for light nuclei, the double-differential cross section of n＋^14N reactions at En=14.2 MeV have been analyzed. In the case of n＋^14N reactions, the reaction mechanism is very complex, there are over one hundred opened partial reaction channels even at incident energy     

Neutron Total Cross Sections of 239Pu from Transmission Measurements in the Energy Range of 1–500keV

The average neutron total cross sections of ²³⁹Pu were obtained in the energy range of 1~500 keV from the high resolution transmission measurements performed by Harvey et al. at the Oak Ridge Electron Linear Accelerator (ORELA). In the energy range of 1~10 keV, the average effective cross sections of three samples were extrapolated to the total cross section for zero sample thickness. Above 10 keV the resonance self-shielding corrections to the effective cross sections of the thick sample were calculated by simulation of the cross sections from the resonance parameters. The results are given with 2% to 4% accuracy in the energy range of 1~10 keV and with better than 1% accuracy in the energy range above 10 keV. They are particularly useful to meet the needs of accurate experimental data in the energy range of 1~50 keV.     

Progress on 14 MeV Neutron Activation Cross Section Measurement at Lanzhou University

Radioactivity in fusion reactors is primarily induced by D-T neutrons and depends entirely on the materials chosen for constructing the reactor components. A lot of work on measurement and evaluation of activation cross sections for 14 MeV neutrons has been done recently. The development of a comprehensive activation data library for fusion applications is also being developed. The needs for activation cross sections leading to the production of     

Theoretical Analysis of Neutron Double-Differential Cross Section of n ~(14)N at 14.2 MeV

By using a new reaction model for light nuclei, the double-differential cross section of n 14N reactions at En=14.2 MeV have been analyzed. In the case of n 14N reactions, the reaction mechanism is very complex, there are over one hundred opened partial r…     

Theoretical Analysis of Neutron Double-Differential Cross Section of n ~(19)F at 14.2 MeV

A new reaction model for light nuclei of 1p shell is expanded to 19F with 2s-1d shell nucleus. The double-differential cross sections of total outgoing neutron for n 19F reactions at En = 14.2 MeV are calculated and analyzed, and the calculated results ag…     

Neutron Emission Spectra of Some Structural Fusion Materials at 26.8 and 45.2 MeV Alpha Incident Energies

In this study, neutron-emission spectra produced by (α,xn) reactions for some structural fusion materials such as ²⁷Al, ⁵³Cr, ⁵⁶Fe and ^58,60,62Ni have been investigated. Hybrid model, geometry dependent hybrid model and full exciton model have been used to calculate the pre-equilibrium neutron-emission spectra. For the reaction equilibrium component, Weisskopf–Ewing model calculations have been preferred. The mean free path parameter’s effect for (α,xn) neutron-emission spectra has been examined. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.     

Calculation of Cross Sections for n ~(63)Cu Reaction

Based on the relevant experimental data, and optical model, evaporation model, Jπ-dependent exciton model, and the pick-up mechanism of cluster pre-formation, neutron induced reaction cross sections, the energy spectrum, angular distribution, double differential cross section and γ-production data were calculated for ~(63)Cu at incident neutron energies below 20 MeV. The calculated results were compared with experimental data.     

Alpha Production Cross Sections for Some Target Fusion Structural Materials up to 35 MeV

In the next century, because of the worldwide energy shortage, human life will badly be affected. Nuclear fusion energy is the remarkable solution to the rising energy challenges because it has the great potential for sustainability, economic and reliability. There have been many research and development studies to get energy from fusion. Moreover, the neutron induced reaction cross section data around 14–15 MeV are need to the design and development of nuclear fusion reactors. Thus, the working out the systematics of (n,α) reaction cross sections is very important and necessary for the definition of the excitation curves at around 14–15 MeV energy. In this study, neutron induced reaction cross sections for structural fusion materials such as Sc (Scandium), Co (Cobalt), Ni (Nickel), Cu (Copper), Y (Yttrium), Mo (Molybdenum), Zr (Zirconium) and Nb (Niobium) have been investigated for the (n,α) reactions. The new calculations on the excitation functions of ⁴⁵ Sc(n,a) ⁴² K, ⁵⁹ Co (n,a) ⁵⁶ Mn, ⁶² Ni(n,a) ⁵⁹ Fe, ⁶³ Cu(n,a) ⁶⁰ Co, ⁶⁵ Cu(n,a) ⁶² Co, ⁸⁹ Y(n,a) ⁸⁶ Rb, ⁹² Mo(n,a) ⁸⁹ Zr, ⁹⁸ Mo(n,a) ⁹⁵ Zr, ⁹² Zr(n,a) ⁸⁹ Sr, ⁹⁴ Zr(n,a) ⁹¹ Sr and ⁹³ Nb(n,a) ⁹⁰ Y reactions have been carried out up to 35 MeV incident neutron energies. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. The equilibrium effects of the excitation functions for the investigated reactions are calculated according to the Weisskopf-Ewing model. Additionaly, in the present work, the (n,α) reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14–15 MeV energy. The calculated results have been discussed and compared with the available experimental data taken from EXFOR database.     

Further Analysis of Neutron Double-Differential Cross Section of n＋^16O at 14.1 and 18 MeV

By using a new reaction model for light nuclei, the double-differential cross section of total outgoing neutron with LUNF code for n＋^16O reactions at En=14.1 MeV and 18 MeV have been calculated and analyzed. The opened reaction channels, which have contribution to emit the neutrons, are listed in detail. To improve the fitting results the direct inelastic scattering mechanism is involved. The calculated results agree fairly well with the experimental data at En= 14.1 MeV and the deviation from calculated results and     

Cross Section Measurement in Neutron Energy Range of 6～12 MeV

Introduction The cross section measurements in neutron energy range from 6 to 12 MeV for the reactions with low threshold are very important to obtain a whole excitation function and to make datum eveluation. But in this energy range, purely monoenergitic neutron source is not available, which make the measured data very few. And there is a serious effect of low energy neutrons on the activation cross section measurement. The correction for the effect of the low energy neutrons are not sufficient for some available data, which cause the published data largely discrepant.