Monte carlo calculations and experimental results of bonner spheres systems with a new cylindrical helium-3 proportional counter
H.Muller, F.Fernández, L.Van Ryckeghem, P.Alexandre, T.Bouassoule, J-L.Pochat and M.Tomas
International Workshop on Neutron Field Spectrometry in science, technology and radiation protection, Pise 2000
inThe experimental results on neutron energy spectra, integral fluences and equivalent dose measurements performed by mean of a Bonner sphere system placed inside the containment building of the Vandellos II Nuclear Power Plant (Tarragona, Spain) are presented. The equivalent dose results obtained with this system are compared to those measured with different neutron area detectors (Berthold, Dineutron, Harwell). A realistic geometry model of the Bonner sphere system with a new cylindrical counter type “F” (0,5NH1/1KI – Eurisys Mesures) and with a set of 8 polyethylene moderating spheres is described in detail. The response function in fluence of this new device, to mono-energetic neutrons from thermal energy to 20 MeV, is calculated by the MCNP-4B code for each moderator sphere. The system has been calibrated at irsn Cadarache facility for ISO Am-Be calibrated source and thermal neutron field, then the response functions has been confirmed by measurements at PTB (Germany) for ISO recommended energies of mono-energetic neutrons and with the CANEL irsn facility which simulates realistic fields.
This work was done in collaboration with University of Barcelona (Spain).