Set-up of a passive Bonner sphere system for neutron spectrometry at mixed fields with predominant photon component based on activation detector.
A passive Bonner sphere system (BSS), based on thermal neutron activation detectors, was developed to perform neutron spectrometry in pulsed and very intense (n-gamma) 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 gamma-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 (252)Cf source is given as well.
Amgarou
K
K
Institut de Radioprotection et de Sûreté Nucléaire, BP 3, 13115 Saint-Paul-lez-Durance Cedex, France. khalil.amgarou@irsn.fr
Lacoste
V
V
Muller
H
H
Fernández
F
F
D004867:Equipment Design; D019544:Equipment Failure Analysis; D009502:Neutrons; D017785:Photons; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation*; D014159:Transducers