Neutron H*(10) estimation and measurements around 18Â MV linac

•H*(10) measurements in three points were carried out around 18 MV linac.•NCRP 151 equations allowed to estimate the dose at the door and the source strength.•A MCNPX model of the linac head was developed to calculate H*(10) due to photoneutrons.•The measurements and MCNPX calculation were compared.

Thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the dose of neutron radiation in a treatment room with a linear electron accelerator of 18 MV. Measurements were carried out through neutron ambient dose monitors which include pairs of thermoluminescent dosimeters TLD 600 (6LiF: Mg, Ti) and TLD 700 (7LiF: Mg, Ti), which were placed inside a paraffin spheres. The measurements has allowed to use NCRP 151 equations, these expressions are useful to find relevant dosimetric quantities. In addition, photoneutrons produced by linac head were calculated through MCNPX code taking into account the geometry and composition of the linac head principal parts.