Modelling of the Dissolution of Silicate Glasses by a Monte-Carlo Code (ETCH)

1986 ◽  
Vol 84 ◽  
Author(s):  
J-C. Dran ◽  
Y. Langevin ◽  
E. Doorhyee ◽  
J-C. Petit
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Chemical Composition ◽  
Percolation Threshold ◽  
Linear Combination ◽  
Solid Solutions ◽  
Etch Rate ◽  
Silicate Glasses ◽  
Monte Carlo Code ◽  
Different Types

AbstractA Monte-Carlo code has been developed to infer dissolution rates of silicate glasses from their chemical composition. The glasses are considered as solid solutions of oxides and silicates, being divided into elementary cells of network formers, in which network modifiers can be incorporated. The different types of cells are randomly distributed and a resistance capacity to dissolution is assigned to each cell. We have tested the case where each cell is removed in a constant time as soon as it is in contact with the solution and a second one where each cell is dissolved in a time depending on the number of already dissolved neighbor cells. The first hypothesis leads to a percolation threshold when the proportion of fast etching cells reaches 25 %. Above, the dissolution front progresses via contiguous channels of fast etching cells. In the second hypothesis the variations of the etch rate with the proportions of each component are much closer to a linear combination of individual etch rates. These predictions have been successfully compared to experimental data on different series of silicate glasses of increasing complexity. Such a treatment could be straightforwardly extended to nuclear glasses.

scholarly journals Determination of 14C, 55Fe, 63Ni and gamma emitters in activated RPV steel samples: a comparison between calculations and experimental analysis

2019 ◽  
Vol 323 (1) ◽  
pp. 399-413 ◽  
Author(s):  
Anumaija Leskinen ◽  
Susanna Salminen-Paatero ◽  
Antti Räty ◽  
Merja Tanhua-Tyrkkö ◽  
Taneli Iso-Markku ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Experimental Analysis ◽  
Monte Carlo Code ◽  
Rpv Steel ◽  
Hpge Detectors ◽  
Standard Geometry ◽  
Different Types ◽  
Radioanalytical Procedures ◽  
Reactor Pressure

AbstractDetermination of 14C, 55Fe, 63Ni and gamma emitters in two different types of activated reactor pressure vessel (RPV) steel samples were carried out. The gamma emitters were analysed using HPGe detectors with ISOCS and standard geometry calibrations. Two radioanalytical procedures for the 14C, 55Fe, 63Ni analysis were developed using inactive samples and activated samples were analysed using modified procedures. A Monte Carlo code was used for the modelling of the activation results. The obtained measured and calculated results were comparable.

ATMOCOSMICS: A GEANT 4 CODE FOR COMPUTING THE INTERACTION OF COSMIC RAYS WITH THE EARTH'S ATMOSPHERE

2005 ◽  
Vol 20 (29) ◽  
pp. 6802-6804 ◽  
Author(s):  
L. DESORGHER ◽  
E. O. FLÜCKIGER ◽  
M. GURTNER ◽  
M. R. MOSER ◽  
R. BÜTIKOFER
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Monte Carlo Code ◽  
Earth’S Atmosphere ◽  
Simulation Results ◽  
Earth's Atmosphere

We have developed a new Monte Carlo code called ATMOCOSMICS based on GEANT 4 that simulates the interaction of cosmic rays with the Earth's atmosphere. The code allows to compute the flux of secondaries (e-, e+, protons, neutrons, gammas, muons, pions, …) at user-defined atmospheric depths and/or altitudes. Profiles of the energy deposited by atmospheric shower particles into the atmosphere vs depth and/or altitude can be calculated. We present examples of simulation results obtained with the code, and compare them with experimental data.

Monte Carlo calculations for transport due to MHD modes

1990 ◽  
Vol 44 (3) ◽  
pp. 405-430 ◽  
Author(s):  
Alkesh Punjabi ◽  
Allen Boozer ◽  
Maria Lam ◽  
Myung-Hee Kim ◽  
Kathy Burke
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Monte Carlo ◽  
Spatial Variation ◽  
Diffusion Coefficients ◽  
Equations Of Motion ◽  
Transport Coefficients ◽  
Particle Diffusion ◽  
Monte Carlo Code ◽  
Magnetic Surfaces

The three basic mechanisms that produce either classical or anomalous transport are spatial variation of magnetic field strength, spatial variation of electrostatic potential in magnetic surfaces, and loss of magnetic surfaces. A Monte Carlo code is written to study transport due to these three mechanisms interacting with collisional effects. The equations of motion are obtained from the canonical drift Hamiltonian, but non-canonical co-ordinates are used to simplify the integrations. The code is applied to the reversed-field-pinch ZT-40 and the Tokapole II. For ZT-40 the Bessel-function model is used to represent the magnetic field geometry. The effects of pitch-angle scattering, loop voltage and the break-up of magnetic surfaces resulting from resistive MHD perturbations on the drift particle trajectories are illustrated. The particle diffusion coefficients are obtained for varying amplitudes of resistive MHD perturbations. For Tokapole II the spectrum of both the ideal and resistive MHD perturbations is constructed from the experimental data. The drift trajectories for trapped and passing electrons in the presence of such perturbations are obtained. The particle diffusion coefficients for the neo-classical regime in Tokapole II are obtained for varying collision frequency. By comparing the transport coefficients for various groups of particles with the experimental data, we hope to obtain far more information on the transport mechanisms than can be obtained by the standard confinement time measurements. The various groups of particles that can be studied using the code include runaway electrons, thermal electrons, and both passing and trapped diagnostic beam ions.

Diffraction effects calculated for structural models of K-saturated montmorillonite containing different types of defects

Clay Minerals ◽  
1984 ◽  
Vol 19 (4) ◽  
pp. 541-561 ◽  
Author(s):  
V. A. D. Rits ◽  
A. Plançon ◽  
B. A. Sakharov ◽  
G. Besson ◽  
S. I. Tsipursky ◽  
...  
Keyword(s):  
Experimental Data ◽  
Chemical Composition ◽  
Structural Characteristics ◽  
Stacking Faults ◽  
Structural Models ◽  
Different Types ◽  
Diffraction Patterns ◽  
Diffraction Effects ◽  
The Relationship ◽  
Independent Parameters

AbstractThe general approach to the problem of the real structure of smectites requires an analysis based on the relationship between structural characteristics and diffraction patterns. This paper, which considers only the models corresponding to dioctahedral smectites saturated by K-cations and collapsed, includes: 1. Successive consideration of all models which are crystallochemically possible. These models may differ in (i) the structure and chemical composition of layers and interlayer spaces; (ii) the azimuthal orientations, translations and the mode of alternation of the layers; (iii) independent parameters which describe quantitatively the models (e.g. abundance of each type of layer, probability parameters defining the succession of layers, …). 2. Calculation, in all accessible domains of reciprocal space, of the distribution of intensities and profile variations, obtained by changing only one parameter at a time, that defines one type of structural feature (e.g. cation distribution in individual layers, stacking of the layers, nature of stacking faults, …). 3. A systematical analysis of the calculated diffraction patterns to establish the diffraction criteria which will help to interpret the experimental data explicitly.

FLUKA simulation yields in a comparison with theoretical and experimental yields relevant to 89Zr produced in the 89Y(p,n) reaction

2019 ◽  
Vol 107 (12) ◽  
pp. 1195-1201 ◽  
Author(s):  
Shaban Abd-Allah Kandil ◽  
Ulrich W. Scherer
Keyword(s):  
Monte Carlo ◽  
Simulated Data ◽  
Low Energy ◽  
Monte Carlo Code ◽  
Pencil Beam ◽  
High Importance ◽  
Energy Beam ◽  
Intermediate Energies ◽  
Experimental Parameters ◽  
Different Types

Abstract The high importance of zirconium-89 (T1/2 = 78.41 h) is related to its applications in medical imaging. It can be produced at low-energy cyclotrons by the reaction 89Y(p,n)89Zr. There exist several publications on its production at low and intermediate energies but there is discrepancy with simulated data. In this study we considered the experimental parameters for four different types of yttrium foil targets reported in literature. The experimental parameters considered were the target geometry, beam profile, and angle of the target relative to the beam during irradiation. The Monte-Carlo code FLUKA was used to calculate production yields. The resulting values obtained by FLUKA from pencil beam or spread energy beam were compared to the theoretical yields obtained from the excitation function and the experimental ones. The FLUKA prediction for 89Z-yield reached ≈50 MBq/μA · h which agrees to a high extent with experimental and theoretical yields reported for the different targets.

Sign in / Sign up

Export Citation Format

Share Document