Photon transport

For optically thick samples, which is the more interesting case applicable to the majority of experiments, Eqs. (1) — (3) have to be combined with the photon-transport equation ... 

Multiple scatter by its very nature arises in several uncorrelated scatter interactions, and its amplitude is often insensitive to the precise composition of the object under investigation. Its spatial variation by the same token is often small [3], A position-independent multiple scatter component can be judiciously estimated from calibration measurements or from Monte Carlo photon transport simulation programs and subtracted as necessary from experimental profiles. 

Alexander, M., Corredig, M., and Dalgleish, D.G. (2006). Diffusing wave spectroscopy of gelling food systems the importance of the photon transport mean free path (I ). Food Hydrocolloids. 20, 325-331. 

Karawkow 1, Rogers DWO. (2003) The EGSnrc code system Monte Carlo simulation of electron and photon transport. NRC Report PIRS-701 (fomth printing). 

According to quantum theory, radiation consists of photons (= light particles), that move at the velocity of light and have no rest mass. They transfer energy, whereby each photon transports the energy quantum... 

Efficiency yields of re-absorption and re-emission processes have been studied as part of an attempt to understand the problem of photon transport in luminescent solar concentrators. The results suggest that the mean photon transport length is proportional to the square root of the surface area of the concentrator for all geometries. 

A. Fasso, A. Ferrari and P. R. Saia, Electron-photon transport in FLUKA status (eds A. Kling, F. Barao, M. Nakagawa, L. Tavora, P. Vaz), Proceedings of the Monte Carlo 2000 Conference, Lisbon, October 23-26 2000, Springer, Berlin, 2001, pp. 159-164. 

W. A. Rhoades and R. L. Childs, An Updated Version of the DOT-IV One- and Two-Dimensional Neutron/Photon Transport Code with Space Dependent Mesh and Quadrature," ORNL/5851,1982. 

Berger, M. J., and Seltzer, S. M., ETRAN Monte Carlo Code System for Electron and Photon Transport Through Extended Media, NBS-9836 and NBS-9837 (1968). 

The definition of how many atomic layers constitute the surface region depends on the surface phenomena under investigation. For example, one atomic or molecular layer can be responsible for most surface chemical properties, whereas almost 10 layers are required to investigate surface effects in electron or photon transport. 

The Photon Transport Problem and Self-Absorption LSC Gain and Efficiency... 

B riesmeister, J. F. 1990. MCNP-A general Monte Carlo code for neutron and photon transport. Version 4.2. Technical Report LA-7396-M, Los Alamos National Laboratory. 

In equation 6.23, s is measured along a chosen direction for photon transport in space (H). The spectral specific intensity must not be confused with radiation density fluxes. They are equal only for unidirectional irradiation, a case very distant from the general one. Radiation may be arriving at one point inside a photochemical reactor from all directions in space. For a photochemical reaction to occur, this radiation must be absorbed by an elementary reacting volume (a material point in space) thus, pencils of radiation coming from all directions must cross the whole elementary surface that bounds such an element of volume. Consequently, the important photochemical property is the spectral incident radiation (or spectral spherical irradiance) given by... 

Where [0i, 62] and [< i, ( 2] are the integration limits that define the space from which radiation arrives at the point of incidence. For each point of incidence, in practice, these limits are defined by the extension of the lamp (its diameter and its length). Thus, to evaluate the LVRPA we must know the spectral specific intensity at each point inside the reactor. Its value can be obtained from the photon transport equation (equation 6.23). 

Working photon transport equation. Going back to equation 6.28 one can neglect the transient term and substitute the different constitutive relationships. After defining a directional coordinate s along the ray path, from elementary calculus it can be written... 

Durian DJ Influence of boundary reflection and refiraction on diffusive photon transport, Phys Rev E 50 857-866, 1994. 

The interest in functional organic-inorganic nanocomposites has grown tremendously in the last two decades thanks to the development of nanotechnologies that allow the production of nanostructured components with unique physical properties and features such as superparamagnetism, ferromagnetism, size-dependent band-gap, and electron and photon transport. 

Compositional modification. As suggested by Eq.(2), the thermal conduction by phonon transport can be reduced by increasing the mean atom weight (M/m) of the material. The major trends in compositions for reducing and/or stabilising thermal conductivity are based on zirconia modified by rare-earth (lanthanide) oxide (REO), since they have a higher atom mass. These dopants, not only reduce the phonon transport, but also reduce the photon transport (radiative) by introducing vacancies [44],... 

DUANE, B.H., Neutron and Photon Transport, Plane-Cylinder-Sphere, G. E.-ANPD Program S, Variational Optimum. Formulation, General Electric Aircraft Nuclear Propulsion Department, XDC 59-9-118 (1959). 

LASL Group TD-6, MCNP-A General Monte Carlo Code for Neutron and Photon Transport, LA-7396-M, Los Alamos Scientific Lab. (July 1978). 

N. R. CANI LORE et id.. RCPOl-A Monte Carlo Program for Solving Neutron and Photon Transport Problems in Three-Dimensional Geometry with Detailed Ene y Description, WAPD-TM-1267, Bettis Atomic Power Lab. (Aug. 1978). 

The latest development is now to combine continuous photochemistry with microstmctured equipment. Only very recenfly photochemical conversions in microreactors have received a considerable amount of attention due to the problem often encountered in conventional photoreactors that the distribution of radiation is inhomogeneous in the reaction zone. During the scale-up process, such inhomogeneities often require intensive modeling and design considerations usually on the basis of photon transport models [66], and such models have been, for example, developed for biomedical and analytical purposes [67]. The problem of the intensity distribution in a reactor is illustrated in Figure 3.10. It is obvious that spatial restriction of the irradiation zone in a microphotoreactor to a... 

Reactor physical characteristics have also drawn much attention. The control rod worth, including the differential worth and integral worth, were calculated by the Monte Carlo code for neutron and photon transport (MCNP) for the 2 MW TMSR-SE (Zhou and Liu, 2013). The measurement of the neutron energy spectrum was also theoretically and experimentally studied (Zhou, 2013). Parametric study of the thorium-uranium conversion rate was conducted to optimize the core structure for the improvement of the economics of the TMSR using the standardized computer analyses for licensing evaluation (SCALE) code (Wang and Cai, 2013). 

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