scholarly journals Our Future Nuclear Data Needs

2019 ◽  
Vol 69 (1) ◽  
pp. 109-136 ◽  
Author(s):  
Lee A. Bernstein ◽  
David A. Brown ◽  
Arjan J. Koning ◽  
Bradley T. Rearden ◽  
Catherine E. Romano ◽  
...  
Keyword(s):  
Cross Sections ◽  
Evaluation Process ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Fission Reaction ◽  
Nuclear Science ◽  
Evaluation Methodologies ◽  
Decay Properties ◽  
Future Challenges ◽  
Reaction Cross Sections

A well-established knowledge of nuclear phenomena including fission, reaction cross sections, and structure/decay properties is critical for applications ranging from the design of new reactors to nonproliferation to the production of radioisotopes for the diagnosis and treatment of illness. However, the lack of a well-quantified, predictive theoretical capability means that most nuclear observables must be measured directly and used to calibrate empirical models, which in turn provide the data needed for these applications. In many cases, either there is a lack of data needed to guide the models or the results of the different measurements are discrepant, leading to the development of evaluation methodologies to provide recommended values and uncertainties. In this review, we describe the nuclear data evaluation process and the international community that carries it out. We then discuss new measurements and improved theory and/or modeling needed to address future challenges in applied nuclear science.

scholarly journals Critical review of CIELO evaluations of n+ 235U, 238U using differential experiments

2018 ◽  
Vol 4 ◽  
pp. 27 ◽  
Author(s):  
Roberto Capote ◽  
Andrej Trkov
Keyword(s):  
Cross Sections ◽  
Critical Review ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Reaction Models ◽  
Reaction Channels ◽  
Data Files ◽  
Integral Data ◽  
Evaluated Nuclear Data ◽  
Reaction Cross Sections

Key reactions have been selected to compare JEFF-3.3 (CIELO 2) and IAEA CIELO (CIELO 1) evaluated nuclear data files for neutron induced reactions on 235U and 238U targets. IAEA CIELO evaluation uses reaction models to construct the evaluation prior, but strongly relied on differential data including all reaction cross sections fitted within the IAEA Neutron Standards project. The JEFF-3.3 evaluation relied on a mix of differential and integral data with strong contribution from nuclear reaction modelling. Differences in evaluations are discussed; a better reproduction of differential data for the IAEA CIELO evaluation is shown for key reaction channels.

scholarly journals Theoretical calculation and evaluation of neutron inducedreactions on Pu isotopes

2020 ◽  
Vol 239 ◽  
pp. 03008
Author(s):  
Hairui Guo ◽  
Yinlu Han ◽  
Tao Ye ◽  
Weili Sun ◽  
Wendi Chen
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Driven Systems ◽  
Intranuclear Cascade ◽  
Pu Isotopes ◽  
Design Requirements ◽  
Accelerator Driven Systems ◽  
Reaction Cross Sections

The nuclear data on n+239,240,242,244Pu reactions for the incident energy up to 200 MeV are consistently calculated and evaluated in order to meet the design requirements of Generation-IV reactors and accelerator driven systems. The optical model, the distorted wave Born approximation theory, the Hauser-Feshbach theory, the fission model, the evaporation model, the exciton model and the intranuclear cascade model are used in the calculation, and new experimental data are taken into account. Our data are compared with experimental data and the evaluated data from JENDL-4/HE and TENDL. In addition, the variation tendency of reaction cross sections related to the target mass numbers is obtained, which is very important for the prediction of nuclear data on neutron-actinides reactions because the experimental data are lacking.

New empirical formula for calculating (n,p) reaction cross-sections at 14.5MeV neutrons

2020 ◽  
Vol 29 (08) ◽  
pp. 2050052
Author(s):  
Dashty T. Akrawy ◽  
Ali H. Ahmed ◽  
E. Tel ◽  
A. Aydin ◽  
L. Sihver
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Empirical Formula ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Section Data ◽  
Nuclear Data Library ◽  
Number Formula ◽  
New Formula ◽  
Reaction Cross Sections

An empirical formula to calculate the ([Formula: see text], [Formula: see text] reaction cross-sections for 14.5[Formula: see text]MeV neutrons for 183 target nuclei in the range [Formula: see text] is presented. Evaluated cross-section data from TENDL nuclear data library were used to test and benchmark the formula. In this new formula, the nonelastic cross-section term is replaced by the atomic number [Formula: see text], while the asymmetry parameter-dependent exponential term has been retained. The calculated results are presented in comparison with the seven previously published formulae. We show that the new formula is significantly in better agreement with the measured values compared to previously published formulae.

Systematics of (n,p) reaction cross-sections for light element target nuclei at 14.5MeV neutrons

2018 ◽  
Vol 27 (10) ◽  
pp. 1850079 ◽  
Author(s):  
Ali Hassan Ahmed
Keyword(s):  
Cross Sections ◽  
Empirical Formula ◽  
Light Element ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Incident Neutron ◽  
Number Range ◽  
Proton Separation Energy ◽  
Nuclear Data Library ◽  
Reaction Cross Sections

The systematics of neutron-induced reactions at 14.5[Formula: see text]MeV are of great importance to describe the excitation of nuclei for the [Formula: see text] reactions. In this study, a new empirical formula is obtained by introducing the proton separation energy to the principal empirical formula for estimating the [Formula: see text] reaction cross-sections for 77 nuclei in the light element mass number range [Formula: see text] at the incident neutron energy of 14.5[Formula: see text]MeV. The calculated results are compared with the evaluated data declared by the TENDL nuclear data library. The predictions of our formula reveal better agreement with the experimental data than the results obtained from the previous suggested formulae.

scholarly journals NDPlot - A plotting tool for nuclear data

2020 ◽  
Vol 239 ◽  
pp. 10004
Author(s):  
Yongli Jin ◽  
Xi Tao ◽  
Jimin Wang ◽  
Nengchuan Shu ◽  
Jing Qian ◽  
...  
Keyword(s):  
Cross Sections ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Angular Distributions ◽  
Current Version ◽  
Energy Distributions ◽  
Application System ◽  
Secondary Particles ◽  
Beta Version ◽  
Reaction Cross Sections

NDPlot is an efficient plotting tool for nuclear data. It is not only a plotting tool, but also an integrated application system. The first beta version of NDPlot was released in October 2018. The current version is 0.94 beta. NDPlot can plot experimental and evaluated data of reaction cross sections, angular distributions of secondary particles, energy distributions of secondary particles and product energy-angle distributions etc. It also provides data processing functions such as curve summation capability to meet user’s requirements.

scholarly journals Measurement of (n, xnγ) reaction Cross-sections on natural lead using in-beam gamma-Ray spectroscopy

2003 ◽  
Vol 18 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Mila Pandurovic ◽  
Strahinja Lukic ◽  
Paule Baumann ◽  
Stpehane Hilaire ◽  
Jasmina Jeknic ◽  
...  
Keyword(s):  
Cross Sections ◽  
Nuclear Reactor ◽  
Gamma Ray ◽  
Nuclear Data ◽  
High Energy ◽  
Reaction Cross ◽  
Universal Method ◽  
Reactor Technology ◽  
Starting Point ◽  
Reaction Cross Sections

New concepts in nuclear reactor technology require precise neutron reaction data in the intermediate and high energy range. At present, experimental and evaluated nuclear data, particularly for (n, xn) reactions, are very scarce. Moreover, real discrepancies exist between different databases. The lack of experimental data is essentially due to the difficulty of measuring (n, xn) reactions. No universal method applicable to all isotopes exists. One of the possible methods is the in-beam y-ray spectroscopy and neutron time of flight technique on white neutron beams. In this way one actually directly measures (n, xny) reaction cross-sections. These serve as a starting point in the subsequent derivation of (n, xn) reaction cross-sections using nuclear models. This method was applied with a natural lead sample at me GELLNA white neutron beam facility in Geel, Belgium.

Measurement and covariance analysis of 59Co(n, 2n)58Co reaction cross sections at the effective neutron energies of 11.98 and 15.75 MeV

2018 ◽  
Vol 106 (11) ◽  
pp. 877-884 ◽  
Author(s):  
Santhi Sheela Yerraguntla ◽  
Haladhara Naik ◽  
Manjunatha Karantha ◽  
Srinivasan Ganesan ◽  
Suryanarayana Venkata Saraswatula ◽  
...  
Keyword(s):  
Cross Sections ◽  
Present Experiment ◽  
Nuclear Data ◽  
Reaction Cross ◽  
Correlation Technique ◽  
Effective Neutron ◽  
Data Libraries ◽  
Nuclear Data Libraries ◽  
Evaluated Nuclear Data ◽  
Reaction Cross Sections

Abstract The 59Co(n, 2n)58Co reaction cross sections relative to the cross sections of the 115In(n, n′)115mIn reaction have been measured at the effective neutron energies of 11.98 and 15.75 MeV by using activation and off-line γ-ray spectrometric technique. Neutron beam used in the present experiment was generated from the 7Li(p, n)7Be reaction with the proton energies of 14 and 18 MeV at the 14UD BARC-TIFR Pelletron facility, Mumbai. We also present the covariance information by taking into account the sources of error and the correlations between the attributes influencing the measurements. The 59Co(n, 2n)58Co reaction cross sections from the present work are then compared with the values from different evaluated nuclear data libraries. The micro-correlation technique suggested by Smith was modified to generate the covariance matrix for the measurements of reaction cross sections as the efficiencies of detector for the sample and monitor are correlated.

Formation of α clusters in dilute neutron-rich matter

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 260-264 ◽  
Author(s):  
Junki Tanaka ◽  
Zaihong Yang ◽  
Stefan Typel ◽  
Satoshi Adachi ◽  
Shiwei Bai ◽  
...  
Keyword(s):  
Cross Sections ◽  
Cluster Formation ◽  
Reaction Cross ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Heavy Nuclei ◽  
Α Decay ◽  
Neutron Skin Thickness ◽  
Reaction Cross Sections ◽  
Α Particles

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

scholarly journals 7Be and 8B reaction dynamics at Coulomb barrier energies

2018 ◽  
Vol 184 ◽  
pp. 02015
Author(s):  
E. Strano ◽  
M. Mazzocco ◽  
A. Boiano ◽  
C. Boiano ◽  
M. La Commara ◽  
...  
Keyword(s):  
Cross Sections ◽  
Coulomb Barrier ◽  
Reaction Cross Section ◽  
Optical Model ◽  
Reaction Dynamics ◽  
Reaction Cross ◽  
Total Reaction Cross Section ◽  
Weakly Bound ◽  
Total Reaction ◽  
Reaction Cross Sections

We investigated the reaction dynamics induced by the 7Be,8B+208Pb collisions at energies around the Coulomb barrier. Charged particles originated by both the col- lisions were detected by means of 6 ΔE-Eres telescopes of a newly developed detector array. Experimental data were analysed within the framework of the Optical Model and the total reaction cross-sections were compared together and with the 6,7Li+208Pb colli-sion data. According to the preliminary results, 7Be nucleus reactivity is rather similar to the 7Li one whereas the 8B+208Pb total reaction cross section appears to be much larger than those measured for reactions induced by the other weakly-bound projectiles on the same target.

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