On the fission chamber pulse charge acquisition and interpretation at MINERVE

Fission Chambers (FCs) are widely used as neutron detectors for online flux measurement. The FC current pulse charge is a key observable quantity which depends on specifications such as the filling gas pressure and the FC geometry. In order to study pulse charges, experimental data have been acquired at the Cadarache zero power reactor MINERVE. Two chambers with contrasting specifications have been used. The experimental pulse charge spectrum is interpreted by the mean of a modeling of fission products (FPs) energy deposition within the filling gas. The pulse charge spectrum peaks are found to correspond to FP emitted perpendicularly to the electrodes.