scholarly journals In search of the best nuclear data file for proton induced reactions: Varying both models and their parameters

2020 ◽  
Vol 239 ◽  
pp. 13005
Author(s):  
E. Alhassan ◽  
D. Rochman ◽  
A. Vasiliev ◽  
R.M. Bergmann ◽  
M. Wohlmuther ◽  
...  
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Goodness Of Fit ◽  
Research Work ◽  
Nuclear Data ◽  
Fine Tuning ◽  
Model Parameters ◽  
Large Set ◽  
Model Calculations ◽  
Proton Induced Reactions

A lot of research work has been carried out in fine tuning model parameters to reproduce experimental data for neutron induced reactions. This however is not the case for proton induced reactions where large deviations still exist between model calculations and experiments for some cross sections. In this work, we present a method for searching both the model and model parameter space in order to identify the ’best’ nuclear reaction models with their parameter sets that reproduces carefully selected experimental data. Three sets of experimental data from EXFOR are used in this work: (1) cross sections of the target nucleus (2) cross sections of the residual nuclei and (3) angular distributions. Selected models and their parameters were varied simultaneously to produce a large set of random nuclear data files. The goodness of fit between our adjustments and experimental data was achieved by computing a global reduced chi square which took into consideration the above listed experimental data. The method has been applied for the adjustment of proton induced reactions on 59Co between 1 to 100 MeV. The adjusted files obtained are compared with available experimental data and evaluations from other nuclear data libraries.

scholarly journals Statistical-model calculations for α-capture reactions relevant to the p process

2019 ◽  
Vol 26 ◽  
pp. 228
Author(s):  
C. Fakiola ◽  
I. Karakasis ◽  
I. Sideris ◽  
A. Khaliel ◽  
T. J. Mertzimekis
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Reaction Network ◽  
Reaction Cross ◽  
Model Parameters ◽  
Model Calculations ◽  
Reaction Channels ◽  
Reaction Cross Sections

About 35 nuclides which lie on the neutron deficient side of the isotopic chart cannot be created by the two basic nucleosynthetic processes, the sand the rprocess. Due to scarce experimental data and the vast complexity of the reaction network involved, cross sections and reactions are estimated theoretically, using the Hauser–Feshbach statistical model. In the present work, theoretical calculations of cross sections of radiative α-capture reactions on the neutron–deficient Erbium and Xenon isotopes are presented in an attempt to make predictions inside the astrophysically relevant energy window (Gamow). The particular reactions are predicted to be sensitive branchings in the γprocess path.The most recent versions of TALYS (v1.9) and Fresco codes were employed for all calculations, initially focusing on investigating the influence of the default eight (8) α–nucleus optical potential models of TALYS on reaction cross sections. The theoretical results of both codes are compared and for the reactions where experimental data exist in literature, the optical model parameters were adjusted appropriately to best describe the data and were subsequently used for estimating (α,γ) reaction cross sections. Predictions for the (α,n) reaction channels have also been calculated and studied.

scholarly journals Differential and integral cross sections for electron elastic scattering by ammonia for incident energies ranging from 10 eV to 20 keV

2018 ◽  
Vol 64 (5) ◽  
pp. 498
Author(s):  
Hocine Aouchiche
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Optical Potential ◽  
Large Set ◽  
Quantum Calculation ◽  
Hartree Fock ◽  
Spherical Complex ◽  
Static Part ◽  
Model Point

Differential and integral cross sections for elastic scattering of electron by NH3 molecule are investigated for the energy ranging from 10 eV to 20 keV.  The calculations are carried out in the framework of partial wave formalism describing the target molecule by means of one center molecular Hartree-Fock functions.  A spherical complex optical potential used includes a static part – obtained here numerically from quantum calculation – and fine effects like correlation, polarization and exchange potentials. The results obtained in this model point out clearly the role played by the exchange and the correlation-polarization contributions in particular at lower scattering angles and lower incident energies. Both differential and integral cross sections obtained are compared with a large set of experimental data available in the literature and well agreement is found throughout the scattering angles and whole energy range investigated here.

Colorisation of archival aerial imagery using deep learning

2021 ◽  
Author(s):  
Ryusei Ishii ◽  
Patrice Carbonneau ◽  
Hitoshi Miyamoto
Keyword(s):  
Deep Learning ◽  
Urban Expansion ◽  
Research Work ◽  
Fine Tuning ◽  
Aerial Images ◽  
Model Parameters ◽  
Style Transfer ◽  
Freeze Layer ◽  
Rgb Images ◽  
Japanese Rivers

<p>Archival imagery dating back to the mid-twentieth century holds information that pre-dates urban expansion and the worst impacts of climate change.  In this research, we examine deep learning colorisation methods applied to historical aerial images in Japan.  Specifically, we attempt to colorize monochrome images of river basins by applying the method of Neural Style Transfer (NST).    First, we created RGB orthomosaics (1m) for reaches of 3 Japanese rivers, the Kurobe, Ishikari, and Kinu rivers.  From the orthomosaics, we extract 60 thousand image tiles of `100 x100` pixels in order to train the CNN used in NST.  The Image tiles were classified into 6 classes: urban, river, forest, tree, grass, and paddy field.  Second, we use the VGG16 model pre-trained on ImageNet data in a transfer learning approach where we freeze a variable number of layers.  We fine-tuned the training epochs, learning rate, and frozen layers in VGG16 in order to derive the optimal CNN used in NST.  The fine tuning resulted in the F-measure accuracy of 0.961, 0.947, and 0.917 for the freeze layer in 7,11,15, respectively.  Third, we colorize monochrome aerial images by the NST with the retrained model weights.  Here used RGB images for 7 Japanese rivers and the corresponding grayscale versions to evaluate the present NST colorization performance.  The RMSE between the RGB and resultant colorized images showed the best performance with the model parameters of lower content layer (6), shallower freeze layer (7), and larger style/content weighting ratio (1.0 x10⁵).  The NST hyperparameter analysis indicated that the colorized images became rougher when the content layer selected deeper in the VGG model.  This is because the deeper the layer, the more features were extracted from the original image.  It was also confirmed that the Kurobe and Ishikari rivers indicated higher accuracy in colorisation.  It might come from the fact that the training dataset of the fine tuning was extracted from these river images.  Finally, we colorized historical monochrome images of Kurobe river with the best NST parameters, resulting in quality high enough compared with the RGB images.  The result indicated that the fine tuning of the NST model could achieve high performance to proceed further land cover classification in future research work.</p>

Evaluation of Optical Model Potential Using Neutron Induced Cross Section Reaction for Spherical Uranium-238 Isotope up to 20MeV

2015 ◽  
Vol 59 ◽  
pp. 26-34
Author(s):  
Iman Tarik Al-Alawy ◽  
Ronak Ikram Ali
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Optical Model ◽  
Threshold Energy ◽  
Model Potential ◽  
Model Parameters ◽  
Incident Neutron ◽  
Optical Model Potential

The evaluation are based on mainly on the calculations of the nuclear optical model potential and relevant parameters are collected and selected from References Input Parameter Library (RIPL) which is being developed under the international project coordinated by the International Atomic Energy Agency (IAEA). The analyzing of a complete energy range has done starting from threshold energy for each reaction. The cross sections are reproduced in fine steps of incident neutron energy with 0.01MeV intervals with their corresponding errors. The recommended cross sections for available experimental data taken from EXFOR library have been calculated for all the considered neutron induced reactions for U-238 isotopes. The calculated results are analyzed and compared with the experimental data. The optimized optical potential model parameters give a very good agreement with the experimental data over the energy range 0.001-20MeV for neutron induced cross section reactions (n,f), (n,tot), (n,el), (n,inl), (n,2n), (n,3n), and (n,γ) for spherical U-238 target elements.

Comparative study on the production of 68Ga from proton induced reactions on different targets: Evaluation of experimental data and model calculations

2015 ◽  
Vol 103 (2) ◽  
Author(s):  
A. Azzam ◽  
M. Al-abyad ◽  
A. H. M. Solieman
Keyword(s):  
Experimental Data ◽  
Comparative Study ◽  
Model Calculations ◽  
Proton Induced Reactions

AbstractDifferent routes can be used to produce the PET isotope

scholarly journals Statistical model calculations of the 7Li +11 Β reaction

2019 ◽  
Vol 10 ◽  
pp. 165
Author(s):  
C. Tsabaris ◽  
C. T. Papadopoulos ◽  
R. Vlastou ◽  
A. A. Pakou ◽  
P. A. Assimakopoulos ◽  
...  
Keyword(s):  
Experimental Data ◽  
Statistical Model ◽  
Energy Range ◽  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Coulomb Barrier ◽  
Reaction Channel ◽  
Model Calculations ◽  
The Individual

The 7Li + 11 Β reaction has been studied in the energy range from a little below to about three times the Coulomb barrier by measuring the cross section of the 7- ray transitions in the residual nuclei produced. Statistical compound nucleus calculations have been performed in order to interpret the experimental data as well as to extract cross sections of the individual exit channels. The statistical compound nucleus theory can reproduce rather well the absolute j - ray and the various reaction channel excitation functions.

scholarly journals Thermonuclear Reaction Rates for Reactions Leading to N = 28 Nuclei

1995 ◽  
Vol 48 (1) ◽  
pp. 125
Author(s):  
A.J Morton ◽  
DG Sargood
Keyword(s):  
Statistical Model ◽  
Nuclear Reaction ◽  
Cross Sections ◽  
Optical Model ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Model Parameters ◽  
Thermonuclear Reaction ◽  
Model Calculations ◽  
Reaction Cross Sections

Nuclear reaction cross sections derived from statistical-model calculations have been used in the calculation of thermonuclear reaction rates for 36 nuclei at temperatures that are representative of the interiors of evolving stars and supernovae as nucleosynthesis approaches the production of nuclei with N = 28. The statistical-model calculations used optical-model parameters in the particle channels which had been selected to give the best overall agreement between theoretical and experimental cross sections for reactions on stable target nuclei in the mass and energy ranges of importance for the stellar conditions of interest. The optical-model parameters used, and the stellar reaction rates obtained, are tabulated. Comparisons are made between these stellar rates and those from other statistical-model calculations in the literature.

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.

scholarly journals Optical Model Potential Using CINDA Library for Neutron Induced Cross Section Reactions for Spherical Uranium-235,238 Isotopes

2015 ◽  
Vol 60 ◽  
pp. 66-73
Author(s):  
Iman Tarik Al-Alawy ◽  
Ronak Ikram Ali
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Optical Model ◽  
Threshold Energy ◽  
Model Potential ◽  
Model Parameters ◽  
Incident Neutron ◽  
Optical Model Potential

The calculation are based mainly on the nuclear optical model potential and relevant parameters are collected and selected from References Input Parameter Library (RIPL) which is being developed under the international project coordinated by the International Atomic Energy Agency (IAEA). The analyzing of a complete energy range has done starting from threshold energy for each reaction. The cross sections are reproduced in fine steps of incident neutron energy with 0.01MeV intervals with their corresponding errors. The recommended cross sections for available experimental data taken from CINDA library have been calculated for all the considered neutron induced reactions for spherical U-235 and U-238 isotopes. The calculated results are analyzed and compared with the experimental data. The optimized optical potential model parameters give a very good agreement with the experimental data over the energy range 0.001-20MeV for neutron induced cross section reactions (n,f), (n,tot), (n,el), (n,inl), (n,2n), (n,3n), and (n,γ) for spherical U-235 and U-238 target elements.

scholarly journals Strategic Framework for Parameterization of Cell Culture Models

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 174
Author(s):  
Pavlos Kotidis ◽  
Cleo Kontoravdi
Keyword(s):  
Experimental Data ◽  
Cell Culture ◽  
Sensitivity Analysis ◽  
Goodness Of Fit ◽  
Sampling Methods ◽  
Model Parameters ◽  
Sensitivity Index ◽  
Cho Cell ◽  
Culture Models ◽  
Cell Culture Models

Global Sensitivity Analysis (GSA) is a technique that numerically evaluates the significance of model parameters with the aim of reducing the number of parameters that need to be estimated accurately from experimental data. In the work presented herein, we explore different methods and criteria in the sensitivity analysis of a recently developed mathematical model to describe Chinese hamster ovary (CHO) cell metabolism in order to establish a strategic, transferable framework for parameterizing mechanistic cell culture models. For that reason, several types of GSA employing different sampling methods (Sobol’, Pseudo-random and Scrambled-Sobol’), parameter deviations (10%, 30% and 50%) and sensitivity index significance thresholds (0.05, 0.1 and 0.2) were examined. The results were evaluated according to the goodness of fit between the simulation results and experimental data from fed-batch CHO cell cultures. Then, the predictive capability of the model was tested against four different feeding experiments. Parameter value deviation levels proved not to have a significant effect on the results of the sensitivity analysis, while the Sobol’ and Scrambled-Sobol’ sampling methods and a 0.1 significance threshold were found to be the optimum settings. The resulting framework was finally used to calibrate the model for another CHO cell line, resulting in a good overall fit. The results of this work set the basis for the use of a single mechanistic metabolic model that can be easily adapted through the proposed sensitivity analysis method to the behavior of different cell lines and therefore minimize the experimental cost of model development.

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