Diagram of the treatment room illustrating photon incidence on a laminated barrier, as showed by the MCNP geometry plotter. Dimensions are given in centimeters.
Comparison of measured and calculated neutron spectra due to the incidence of 13.27 MeV gamma rays on lead. Measurements data are taken from Cardman (Ref. 15).
Mesh tally depiction of the neutron fluence density around the treatment room, normalized per starting photon.
Neutron fluence beyond barriers of various thicknesses of lead, for 10 and 15 MeV incident photons.
Total, elastic, and inelastic neutron cross sections for natural lead (ENDF/B-6.4).
Simulated photoneutron angular distribution for the 10 MV spectrum impinging on lead.
Simulated photoneutron spectrum in the patient plane.
Transmission curves for the neutron ambient dose equivalent normalized to 1 Gy of photon absorbed dose at the isocenter beyond a laminated barrier containing 1 tenth value layer of lead, for varying thicknesses of neutron shielding.
Threshold energy for photoneutron emission in metals.
Elemental densities of the materials considered in the simulations.
Neutron ambient dose equivalents outside the accelerator room, normalized to 1 Gy of photon absorbed dose at the isocenter for three thicknesses of lead positioned in one of three locations.
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