A. Bañuelos-Frías, C. Borja-Hernández, K. Guzmán-García, C. Valero-Luna, V. Hernández-Dávila, and H. Vega-Carrillo., Neutron spectra and H*(10) of photoneutrons inside the vault room of an 18 MV LINAC, Rev. Mex. Fís. 58, (2012).