TY - GEN
T1 - Neutron guide shielding for the BIFROST spectrometer at ESS
AU - Mantulnikovs, Konstantins
AU - Bertelsen, Mads
AU - Cooper-jensen, C.p.
AU - Lefmann, Kim
AU - Klinkby, Esben Bryndt
PY - 2016/10/10
Y1 - 2016/10/10
N2 - We report on the study of fast-neutron background for the BIFROST spectrometer at ESS. We investigate the effect of background radiation induced by the interaction of fast neutrons from the source with the material of the neutron guide and devise a reasonable fast, thermal/cold neutron shielding solution for the current guide geometry using McStas and MCNPX. We investigate the effectiveness of the steel shielding around the guide by running simulations with three different steel thicknesses. The same approach is used to study the efficiencies of the steel wall a flat cylinder pierced by the guide in the middle and the polyethylene layer. The final model presented here has a 3 cm thick steel shielding around the guide, 30 cm of polyethylene around the shielding, two 5 mm thick B4C layers and a steel wall at position Z = 38 m, being 1 m thick and 10 m in radius. The final model finally proves that it is sufficient to bring the background level below the cosmic neutron rate, which defines an order of magnitude of the lowest obtainable background in the instruments.
AB - We report on the study of fast-neutron background for the BIFROST spectrometer at ESS. We investigate the effect of background radiation induced by the interaction of fast neutrons from the source with the material of the neutron guide and devise a reasonable fast, thermal/cold neutron shielding solution for the current guide geometry using McStas and MCNPX. We investigate the effectiveness of the steel shielding around the guide by running simulations with three different steel thicknesses. The same approach is used to study the efficiencies of the steel wall a flat cylinder pierced by the guide in the middle and the polyethylene layer. The final model presented here has a 3 cm thick steel shielding around the guide, 30 cm of polyethylene around the shielding, two 5 mm thick B4C layers and a steel wall at position Z = 38 m, being 1 m thick and 10 m in radius. The final model finally proves that it is sufficient to bring the background level below the cosmic neutron rate, which defines an order of magnitude of the lowest obtainable background in the instruments.
U2 - 10.1088/1742-6596/746/1/012027
DO - 10.1088/1742-6596/746/1/012027
M3 - Conference article
SN - 1742-6588
VL - 746
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - 1
M1 - 012027
ER -