Set-up of passive Bonner sphere system for neutron spectrometry at mixed fields with predominant photon component based on activation detectors
Congresss title :NEUDOS 10
Congress town :Uppsala
Congress date :12/06/2006
Journal title : Radiation Protection Dosimetry 126 issue 1-4 Pages 337-341
A passive Bonner sphere system (BSS), based on thermal neutron activation detectors, was developed to perform neutron spectrometry in pulsed and very intense (n-) fields with predominant photon component, as those produced by high energy (>10 MV) medical linear electron accelerators. In this paper, a description of the new system is presented together with an experimental characterisation of a portable Sodium Iodide (NaI) detector and a fixed high-purity Germanium one, both used to measure the induced -activity of the activated materials, respectively, in situ and in the laboratory. The choice of the activated materials is justified according to pre-established practical considerations and physical criteria. The response functions of the entire passive BSS were calculated using the MCNPX code. A preliminary experimental validation with a bare 252Cf source is given as well.