Investigation of some industrial samples based on neutron scattering and absorption / Gamal Mesbah Mohamed Taha ; Supervised Saher Mohamed Darwish , Abdelghani Aly Elabd , Ali Yahya Ellithi

Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Physics

A method was proposed for measuring macroscopic absorption and scattering cross-sections for thermal neutrons. It is based on a Pu-Be neutron source and He-3 neutron detectors assembly. A beam of neutrons was obtained from the source imbedded in a water tank. The macroscopic absorption and scattering cross-sections for thermal neutrons for liquid and solid standard samples characterized with different volumes were calculated.The 3He detectors oriented inside the sample and at 1800 and 00 with respect to the incident neutron beam were used to register neutrons after interaction with the samples.A semi-empirical model was proposed to fit the results. It describes the relative detector responses in terms of a dimensionless variable which depends on the geometrical parameters and cross section of the standard samples used.The model successfully fitted the results obtained.The proposed method was extended and used for correcting thermal neutron self-shielding in large sample neutron activation analysis and prompt gamma ray neutron activation analysis.The results obtained showed that the thermal neutron self-shielding factors collapse to master curves in terms of dimensionless variable lambing the physical, geometrical and nuclear properties of the samples.The method proposed is easy to implement in short time

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