A Monte Carlo study of back-scattered gamma radiation from a broad beam normally incident on an infinitely thick slab

Abstract

The method presented in this paper is an application of the Monte Carlo technique employed in calculating reflected radiation from a broad beam of gamma radiation normally incident on a plane and smooth surface. The reflecting medium is infinitely thick and homogeneous. It should be noted that the results of the calculation are almost 100 per cent accurate for thicknesses over 20 mean free paths ^† and for engineering purposes are useful between 10 and 20 mean free paths within a few per cent of accuracy.

The incident radiation considered here is mono-energetic. In case of a spectrum of energies of the incident radiation the beam first has to be lumped in discrete energy bins and for each bin the mean energy must be evaluated, after which each is used as a mono-energetic radiation.

In order to be able to reuse calculated values without repetition of the computer work it is planned to perform calculations for energies from 0.5 Mev to 10 Mev in 0.5 Mev energy increments and to print the results as a set of tables.

The purpose of this paper is to serve as a practical introduction into the Monte Carlo technique by use of a relatively simple geometry showing a way toward solution of more complicated problems.

* Gibbs and Hill Inc., New York, N.Y., USA.

“Mean free path” is the length of travel of a particle in a medium before it collides with a particle of the medium.

* Gibbs and Hill Inc., New York, N.Y., USA.

“Mean free path” is the length of travel of a particle in a medium before it collides with a particle of the medium.

Notes

* Gibbs and Hill Inc., New York, N.Y., USA.

“Mean free path” is the length of travel of a particle in a medium before it collides with a particle of the medium.