title: MCNP simulation to optimise in-pile and shielding parts of the Portuguese SANS instrument.
abstract: A Small Angle Neutron Scattering instrument is being installed at one end of the tangential beam tube of the Portuguese Research Reactor. The instrument is fed using a neutron scatterer positioned in the middle of the beam tube. The scatterer consists of circulating H2O contained in a hollow disc of Al. The in-pile shielding components and the shielding installed around the neutron selector have been the object of an MCNP simulation study. The quantities calculated were the neutron and gamma-ray fluxes in different positions, the energy deposited in the material by the neutron and gamma-ray fields, the material activation resulting from the neutron field and radiation doses at the exit wall of the shutter and around the shielding. The MCNP results are presented and compared with results of an analytical approach and with experimental data collected after installation.
authors.affiliation: Instituto Tecnológico e Nuclear, Est. Nac. 10, Apartado 21, 2686-953 Sacavém, Portugal. ifg@itn.mces.pt
authors.forename: I F
authors.initials: IF
authors.lastname: Gonçalves
authors.forename: J
authors.initials: J
authors.lastname: Salgado
authors.forename: A
authors.initials: A
authors.lastname: Falcão
authors.forename: F M A
authors.initials: FM
authors.lastname: Margaça
authors.forename: F G
authors.initials: FG
authors.lastname: Carvalho
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005720:Gamma Rays; D015233:Models, Statistical; D009010:Monte Carlo Method; D033363:Neutron Diffraction / Q000295:instrumentation*; D009502:Neutrons; D011174:Portugal; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods*; D011874:Radiometry / Q000379:methods*