Neutron field characteristics of Ciemat´s Neutron Standards Laboratoy

Abstract

Monte Carlo calcultarions were carried out to characterized the neutron field produced by the calibration neutron sources of the Neutron Standards Laboratory at the Research Center for Energy, Environment and Technology (CIEMAT) in Spain. For 241 AmBe and 252 Cf neutron sources, the neutron spectra, the ambien dose equivalent rates and the total neutron fluence were estimated. In the calibration hall, there are everal itmes that modify the neutron field. To evaluate their effects different cases were used, front point-like source in vacuum upto the full model. Additionally, using the full model, the neutron spectra were estimated to different distances along the bench; with these spectra, the total neutron fluence and the ambient dose equivalent rates were calculated. The hall walls induce tha largest changes in the neutron spectra and the respective integral quantities. The free-field neutron spectrum is modified due the room return effect.