Neutron flux measurement channel utilizing the Campbell technique

The Campbell technique for the neutron flux measurement was investigated Th is technique utilises the AC component (noise) of a neutron chamber signal rather then DC component, which is usually used. The Campbell theorem expla ins 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 accomplish ed by one measurement channel. Furthermore, the large pulses of the respons e to neutrons are favoured over small pulses of the response to gamma rays in the ratio of their mean square charge transfer. Due to this fact, the Ca mpbell technique provides an excellent discrimination of the gamma rays in the current operational range of a neutron chamber. The neutron flux measur ement channel with usage? of up to date components was developed and linear ity, accuracy, dynamic range, time response and gamma discrimination were r ested on the experimental reactors VR-I in Prague and Triga in Vienna.