Verification of an Efficient Monte Carlo Model that Interchanges the Geometric Shapes of Plane Source and Detector in Radiation Transport Calculation

A Monte Carlo model with special features for modeling of radiation transport through very thin layers has been presented. Over the decades traditional Monte Carlo model has been used to model highly scattering thin layers in skin and may inaccurately capture the effect of thin layers since their interfaces are not perfectly planar and thicknesses non-uniform. If the Monte Carlo model is implemented without special features then the results of the simulation would show no effect of the outer thin layer since the path length of most photons would be significantly larger than the layer thickness and the resulting predicted photon travel would simply not notice the presence of the layer. Examples of multi-layered media are considered where the effect of a very thin absorbing layers is systematically examined using both the traditional Monte Carlo and that with new features incorporated. The results have profound implications in the diagnostic and therapeutic applications of laser in biomedicine and surgery.

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Monte Carlo Simulation of Backscatter Signals Through Thin Scattering Layers for Biomedical Applications

Volume 3: Biomedical and Biotechnology Engineering ◽

10.1115/imece2014-36352 ◽

2014 ◽

Author(s):

R. Eze ◽

Y. Hassebo

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Path Length ◽

Biomedical Applications ◽

Radiation Transport ◽

Monte Carlo Model ◽

Thin Layers ◽

Radiative Properties ◽

Noninvasive Methods ◽

Space Applications

Monte Carlo simulation of photon transport is formulated to solve transient radiative transfer equation through thin multilayered scattering-absorbing media with inhomogeneous properties. Though thin layers might seem to be geometrically insignificant, contribution of their radiative properties is relevant in predicting the behavior of most bioengineering, biomedical and space applications. Most traditional Monte Carlo models often fail to capture the presence of thin layers and account for its radiative properties. If the Monte Carlo model is implemented without unique features then the results of the simulation would show incorrect effect of thin layers since the path length of most photons would be significantly larger than the layer thickness and the evaluated photon travel path length would simply not feel the existence of the layer. Numerical and algorithmic features for computation of radiation transport through thin scattering and absorbing layers using the traditional Monte Carlo and an enhanced Monte Carlo model with features specifically developed for thin layers is presented and implemented for the analysis of backscattered radiation. It is observed that while Monte Carlo without special features defines the radiative effect of the layers, the refined technique indicates that layers have a great impact on the backscattered light, especially if the layer properties are distinctly different from those of the contiguous layers. The results have significant implications in the study of diagnostic applications of laser in biomedical applications since backscattered light is one of the non-invasive techniques available for detection of diseases and complements other known methods. Analyses of backscattered signals have also found use in the noninvasive methods of medical use especially in skin diagnostics.

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The Use of the MCNP Code for Radiation Damage Calculations

Mathematical Physics and Computer Simulation ◽

10.15688/mpcm.jvolsu.2021.1.5 ◽

2021 ◽

pp. 70-77

Author(s):

Mohammad Hiwa ◽

Keyword(s):

Monte Carlo ◽

Radiation Damage ◽

Cross Section ◽

Neutron Energy ◽

Radiation Transport ◽

Mcnp Code ◽

Transport Calculation ◽

Energy Irradiation ◽

Basic Concepts ◽

The Impact

This work gives a detailed analysis of the result of Monte Carlo physics practical using MCNP. This paper describes basic concepts of the Monte Carlo theory of radiation transport calculation and also discusses the variance and the history method as used in Monte Carlo Problem solving. Therefore, in this exercise the MCNP code has been used to solve and estimate the number of neutron flux. The paper investigated the impact of the primary radiation damage in iron by the neutron energy irradiation. The established measurement of radiation damage is the displacements per atom (dpa) in matter as a function of neutron energy. The simulations were carried out to calculate the dpa cross section.

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EFFECT OF FISSION SOURCE SPECTRUM ON MONTE CARLO CALCULATION OF EX-CORE QUANTITIES

EPJ Web of Conferences ◽

10.1051/epjconf/202124702027 ◽

2021 ◽

Vol 247 ◽

pp. 02027

Author(s):

Eva E. Davidson ◽

Tara M. Pandya ◽

Katherine E. Royston ◽

Thomas M. Evans ◽

Andrew T. Godfrey ◽

...

Keyword(s):

Monte Carlo ◽

Neutron Source ◽

Radiation Transport ◽

Source Spectrum ◽

Detector Response ◽

Monte Carlo Code ◽

Sampling Schemes ◽

Transport Calculation ◽

Water Reactors ◽

Quantities Of Interest

The Consortium for Advanced Simulation of Light Water Reactors (CASL) Virtual Environment for Reactor Applications (VERA) offers unique capabilities to combine highfidelity in-core radiation transport with temperature feedback using MPACT and CTF with a follow-on fixed source transport calculation using the Shift Monte Carlo code to calculate ex-core quantities of interest. In these coupled calculations, MPACT provides a fission source to Shift for the follow-on radiation transport calculation. In past VERA releases, MPACT passed a spatially dependent source without the energy distribution to Shift. Shift then assumed a235U Watt spectrum to sample the neutron source energies. There were concerns that, in cases with burned or mixed oxide (MOX) fuel near the periphery of the core, the assumption of a235U Watt spectrum for the source neutron energies would not be accurate for studying ex-core quantities of interest, such as pressure vessel fluence or detector response. Therefore, two additional options were implemented in VERA for Shift to sample neutron source energies: (1) a nuclide-dependent Watt spectra for235U,238U,239Pu, and241Pu, and (2) to use the standard 51-energy group MPACT spectrum. Results show that the 51-group MPACT spectrum is not suitable for ex-core calculations because the groups have been fine-tuned for in-core calculations. Differences in relative detector response due to235U and nuclide-dependent Watt spectra sampling schemes were negligible; however, the use of nuclide-dependent Watt spectra for vessel fluence calculations was found to be important for fuel cycles with burned and fresh fuel.

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A Monte-Carlo model of xenon resonance radiation transport in a plasma display panel cell: Transition from optically thick to thin regimes

Journal of Applied Physics ◽

10.1063/1.372244 ◽

2000 ◽

Vol 87 (6) ◽

pp. 2700-2707 ◽

Cited By ~ 14

Author(s):

Trudy van der Straaten ◽

Mark J. Kushner

Keyword(s):

Monte Carlo ◽

Radiation Transport ◽

Monte Carlo Model ◽

Resonance Radiation ◽

Plasma Display Panel ◽

Plasma Display ◽

Cell Transition ◽

Panel Cell

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Transformation of a system consisting of plane isotropic source and unit sphere detector into a system consisting of point isotropic source and plane detector in Monte Carlo radiation transport calculation

Journal of Nuclear Science and Technology ◽

10.1080/00223131.2011.649079 ◽

2012 ◽

Vol 49 (2) ◽

pp. 167-172 ◽

Cited By ~ 21

Author(s):

Yoshihito Namito ◽

Hajime Nakamura ◽

Akihiro Toyoda ◽

Kazuhiko Iijima ◽

Hiroshi Iwase ◽

...

Keyword(s):

Monte Carlo ◽

Unit Sphere ◽

Radiation Transport ◽

Isotropic Source ◽

Plane Detector ◽

Transport Calculation

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The thermal-radiative wind in low-mass X-ray binary H1743−322 – II. Iron line predictions from Monte Carlo radiation transfer

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa961 ◽

2020 ◽

Vol 494 (3) ◽

pp. 3413-3421 ◽

Cited By ~ 1

Author(s):

Ryota Tomaru ◽

Chris Done ◽

Ken Ohsuga ◽

Hirokazu Odaka ◽

Tadayuki Takahashi

Keyword(s):

Monte Carlo ◽

Binary Systems ◽

Velocity Structure ◽

Initial Conditions ◽

Radiation Transport ◽

Iron Line ◽

X Ray ◽

Transport Calculation ◽

Small Disc ◽

Absorption Features

ABSTRACT We show the best current simulations of the absorption and emission features predicted from thermal-radiative winds produced from X-ray illumination of the outer accretion disc in binary systems. We use the density and velocity structure derived from a radiation hydrodynamic code as input to a Monte Carlo radiation transport calculation. The initial conditions are matched to those of the black hole binary system H1743−322 in its soft, disc dominated state, where wind features are seen in Chandra grating data. Our simulation fits well to the observed line profile, showing that these physical wind models can be the origin of the absorption features seen, rather than requiring a magnetically driven wind. We show how the velocity structure is the key observable discriminator between magnetic and thermal winds. Magnetic winds are faster at smaller radii, whereas thermal winds transition to a static atmosphere at smaller radii. New data from XRISM (due for launch 2022 January) will give an unprecedented view of the physics of the wind launch and acceleration processes, but the existence of static atmospheres in small disc systems already rules out magnetic winds which assume self-similar magnetic fields from the entire disc as the origin of the absorption features seen.

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