Neutron flux measurement channel utilizing the Campbell technique / Neutronenflußdichtemeßkanal mit Nutzung des Campbell Verfahrens

Abstract

The Campbell technique for the neutron flux measurement was investigated. This technique utilises the AC component (noise) of a neutron chamber signal rather then DC component, which is usually used. The Campbell theorem explains that the root mean square of the AC component of the chamber signal is proportional to the neutron flux (reactor power). Because of the quadratic dependence of the reactor power to the root mean square value, usually the whole current power range of the neutron flux measurement can be accomplished by one measurement channel. Furthermore, the large pulses of the response to neutrons are favoured over small pulses qf the response to gamma rays in the ratio of their mean square charge transfer. Due to this fact, the Campbell technique provides an excellent discrimination of the gamma rays in the current operational range qf a neutron chamber. The neutron flux measurement channel with usage of up to date components was developed, and linearity, accuracy, dynamic range, time response and gamma discrimination were tested on the experimental reactors VR-1 in Prague and Triga in Vienna.