Published September 1986 | Version v1
Report Open

Methematical model of a neutron counting system used for the characteristics control of spontaneously fissioning material

Description

Methods are described for calculating the probabilities, p(m), of detection of m neutrons, inside a split millisecond counting gate, m varying from zero to some units. At the present stage, these methods suppose the source to be very small. Using the generating function concept, they concern both possible modes of the counting system, for opening gates, i.e.: 1) Trigger pulses randomly with regard to the emitted neutrons, 2) Trigger pulses from the detected neutrons themselves. Computed values are finally compared to the measured ones. This comparison seems to be very favourable, since the respective deviations are often lower than 1 %

Availability note (English)

MF available from INIS under the Report Number.

Abstract (French)

On decrit les methodes utilisees pour le calcul des probabilites, p(m), de detection, dans une fenetre de comptage d'une fraction de milliseconde, de m neutrons, m variant de 0 a quelques unites. Ces methodes, au stade actuel, supposent la source ponctuelle. Utilisant le concept de fonction generatrice, elles concernent les deux modes possibles de fonctionnement du dispositif de comptage: 1) declenchement des fenetres de facon aleatoire par rapport aux neutrons emis, 2) declenchement des fenetres par les neutrons detectes eux-memes. On compare finalement des valeurs calculees a celles mesurees: cette comparaison parait tres favorable, les ecarts etant souvent tres inferieurs a 1 %

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Additional details

Additional titles

Original title (French)
Modelisation d'un systeme de comptage neutronique utilise pour la verification des caracteristiques d'un milieu spontanement fissile

Publishing Information

Imprint Pagination
18 p.
Report number
CEA-R--5368