A Monte Carlo model for low energy D–D neutron generators

Author(s):  
Alberto Milocco ◽  
Andrej Trkov ◽  
Mario Pillon
1997 ◽  
Vol 469 ◽  
Author(s):  
M.-J. Caturla ◽  
T. Diaz de la Rubia ◽  
J. Zhu ◽  
M. Johnson

ABSTRACTWe use a kinetic Monte Carlo model to simulate the implantation of low energy Boron in Silicon, from 0.5 to 1 keV, at high doses, 1015 ions/cm2. The damage produced by each ion is calculated using UT-Marlowe, based on a binary collision approximation. During implantation at room temperature,, silicon self-interstitials, vacancies and boron interstitials are allowed to migrate and interact. The diffusion kinetics of these defects and dopants has been obtained by ab initio calculations as well as Stillinger Weber molecular dynamics. Clustering of both self-interstitials, vacancies and boron atoms is included. We also model the diffusion of the implanted dopants after a high temperature annealing in order to understand the transient enhanced diffusion (TED) phenomenon. We observe two different stages of TED During the first stage vacancies are present in the lattice together with interstitials and the diffusion enhancement is small. The second stage starts after all the vacancies disappear and gives rise to most of the final TED.


2021 ◽  
Vol 9 ◽  
Author(s):  
Ning Su ◽  
Yuanyuan Liu ◽  
Li Wang ◽  
Bin Wu ◽  
Jianping Cheng

Cosmic-ray muons are a type of natural radiation with high energy and a strong penetration ability. The flux distribution of such particles at sea level is a key problem in many areas, especially in the field of muon imaging and low background experiments. This paper summarizes the existing models to describe sea-level muon flux distributions. According to different means used, four parametric analytical models and one Monte Carlo model, which is referred to as CRY, are selected as typical sea-level muon flux distribution models. Then, the theoretical values of sea-level muon fluxes given by these models are compared with the experimental sea-level muon differential flux data with kinetic energy values in the range of 1–1,000 GeV in the directions of zenith angles 0° and 75°. The goodness of fit of these models to the experimental data was quantitatively calculated by Pearson’s chi-square test. The results of the comparison show that the commonly used Gaisser model overestimates the muon flux in the low-energy region, while the muon flux given by the Monte Carlo model CRY at the large zenith angle of 75° is significantly lower than that of the experimental data. The muon flux distribution given by the other three parametric analytical models is consistent with the experimental data. The results indicate that the original Gaisser model is invalid in the low energy range, and CRY apparently deviates at large zenith angles. These two models can be substituted with the muon flux models given by Gaisser/Tang, Bugaev/Reyna, and Smith and Duller/Chatzidakis according to actual experimental conditions.


2021 ◽  
Vol 11 (4) ◽  
pp. 445-454
Author(s):  
Gian Marco Contessa ◽  
Nadia Cherubini ◽  
Giada Gandolfo ◽  
Luigi Lepore ◽  
Giuseppe A. Marzo ◽  
...  

Portable neutron generators are one of the most widespread sources of fast neutrons for different applications, from activation analysis to quantitative estimation of fissile and fertile materials in radioactive waste packages. New techniques based on these devices have been developed for homeland security, e.g. neutron interrogations of packages suspected of containing substances such as explosives. When using portable generators determination of radiation protection quantities is affected by a series of boundary conditions that could differ from an experimental set-up to another, and Radiation Protection Experts cannot assess operator exposure without the aid of time-expensive Monte Carlo simulations. As it is impossible to foresee all kind of scenarios involving such applications, and time is often a critical variable, safety assessment requires faster, even if less accurate, tools for exposure evaluation. In this article experimental measurements of dose rates in a real scenario involving a D-T neutron generator are considered, to validate the Monte Carlo model developed. Consequently, it was possible to demonstrate that the calibration factor at 14 MeV for a neutron dosimeter provides conservative dose estimates and to propose a stand-alone, fast, and easy-to-use calculation tool which is usable on field by the Radiation Protection Expert without full Monte Carlo calculations.


2014 ◽  
Vol 41 (6Part11) ◽  
pp. 234-234
Author(s):  
M Constantin ◽  
D Sawkey ◽  
S Johnsen ◽  
H Hsu

1977 ◽  
Vol 21 ◽  
pp. 207-215
Author(s):  
R. Hight ◽  
C. N. Inskeep

A Monte-Carlo model has been developed to calculate the effect entrance windows, or dead layers, have on the spectral shape and the counting efficiency of semiconductor detectors used in the low energy x-ray region (1 – 5 KeV).


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