摘要:

A solution is developed for the problem of determining the cross sections of a physical system by irradiating its outer boundary with a known neutron flux, measuring the exiting flux, and then making suitable use of the known incident and exiting boundary fluxes. Our solution requires the use of delta function (pencil beam) incident boundary fluxes, and detectors that are capable of measuring exiting angular fluxes which are weak delta functions of angle (arising from a line source) over an infinitesimal angular interval comprising the support of the delta function. Our approach, which is significantly different from previously published solutions of this problem, is applicable in general geometries with spatial inhomogeneities.

ISSN:0041-1450    

DOI:10.1080/00411458808230860

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The effects of the electron distribution in velocity, in time or in space (straggling effect) on some parameters as the range and the stopping power are analyzed. An analytical expression of the range and the stopping power is obtained by starting from Boltzmann equation.

ISSN:0041-1450    

DOI:10.1080/00411458808230861

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The subject of this paper is spatial finite-difference approximations to the discrete-ordinate equations for azimuthally symmetric transport of monoenergetic particles in plane-parallel geometry. In previous work it has been shown that almost allclosed linear one-cell functional(CLOF) methods are equivalent to a linear finite-difference method. Here it is shown that any such method that is consistent, in a certain natural sense, is equivalent to a consistent one-step finite-difference approximation to a linear two-point boundary-value problem, in the sense of earlier work of Keller and White. It follows, from observations in this same work, that for CLOF methods consistency impliesbothconvergence and stability.

ISSN:0041-1450    

DOI:10.1080/00411458808230862

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Relations for the elements of the scattering and phase matrices relevant to the single and multiple scattering of polarized light are given in some detail. After a Fourier decomposition of the phase matrix with respect to azimuth has been made, some details of the expansion coefficients are presented.

ISSN:0041-1450    

DOI:10.1080/00411458808230863

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We consider a slab nuclear reactor whose half-thickness a(t) depends on time because of temperature effects due to fission energy. Starting from the neutron transport equation and from the heat conduction equation, we derive a system of nonlinear ordinary differential equations for the average neutron density m(t) and for the half-thickness a(t).

ISSN:0041-1450    

DOI:10.1080/00411458808230864

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Explicit analytical solutions to a nonlinear spatially inhomogeneous model Boltzmann equation are presented for a physical situation of reference, characterized by constant collision frequencies and scattering probability distributions depending only on the velocity after collision. The results obtained are appropriately commented on physical grounds.

ISSN:0041-1450    

DOI:10.1080/00411458808230865

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We prove existence and uniqueness of a couple of nonnegative distributions for an evolution problem modelling the interactions of ions and neutral atoms with charge exchange. Some remarks on asymptotic behaviour are added.

ISSN:0041-1450    

DOI:10.1080/00411458808230866

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We study the initial-value problem for the linear Maxwell-Boltzmann equation in the whole space, by supposing that the collision frequency and the integral operator are unbounded (rigid spheres; pure scatterer). Using the theory of the linear semigroups, we show that this problem has one and only one strong solution for any suitable initial datum. We finally show that the solution is non-negative if the initial datum is non-negative and that mass conservation holds.

ISSN:0041-1450    

DOI:10.1080/00411458808230867

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The singular eigenfunction method for solving transport equations introduced by K. M. Case in 19601has become extremely popular, at least in some circles, because of its close analogy to the classical method of treating partial differential equations, i.e. eigenfunction expansions. Because of a perceived lack of rigor in Case's work, alternate methods were developed later which were supposed to retain most of the advantage that Case's method had over classical Fourier transform methods (Wiener-Hopfl—i.e., elegance—while dispensing with Case's heuristic arguments. These methods were the resolvent integration technique of Larsen-Habetler2and the Hilbert space approach of Rutger Hansel broek3

ISSN:0041-1450    

DOI:10.1080/00411458808230868

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

We show how the FNmethod for one speed neutron transport in finite slabs can be viewed as a transform of a problem on an infinite interval. This allows us to use an analysis based on the singular value decomposition to prove convergence of the method. Unlike previous work, the problem on the infinite interval is not the equation for the flux.

ISSN:0041-1450    

DOI:10.1080/00411458808230869

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor