PASSAGE OF THERMAL NEUTRONS THROUGH A HOT SLAB OF MODERATING MATERIAL

Technical Report · Thu Sep 01 04:00:00 EDT 1960

OSTI ID:4102132

Carley, C M

The effect of scattering collisions on the distributions in speed and direction of thermal neutrons passing through a thin slab of moderating material is studied. The slab is assumed to be composed of a noncapturing monatomic gas, and it is further assumed that no neutron undergoes more than one collision in the slab. Equations are derived and evaluated for the angnlar current density and the speed distribution of the spatial density of neutrons emerging from one side of the slab when thermal neutrons impinge on the other side with an arbitrary current density. A P/sup 2/ approximation is used for the scattering kernel. In the cases studied, variations are made in the arbitrary incurrent and in the thickness of the slab and its temperature and the mass of its atoms. The results show that passage through the slab has very little effect on the distribution of the neutron's directions. The distribution of their speeds is changed very little in form; but, when the slab is hot, the distribution is shifted toward higher speeds. The results indicate that the concept of effective neutron temperature can be applied to the neutrons leaving the slab. A curve is obtained showing the effect of the temperature of the slab on the effective temperature of the neutrons emerging from it. (auth)

• Research Organization: Canadian Westinghouse Co., Ltd. Atomic Energy Div., Hamilton, Ont.
• NSA Number: NSA-15-005786
• OSTI ID: 4102132
• Report Number(s): CWAED-42; AECL-1082
• Country of Publication: Canada
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
COLLISIONS
CROSS SECTIONS
DENSITY
GASES
MASS
MODERATORS
NEUTRONS
PLATES
REACTOR TECHNOLOGY
SCATTERING
TEMPERATURE
THERMAL NEUTRONS
THICKNESS
VELOCITY