Comparison of Photonuclear Data Files Used in Shielding Calculation of a Medical Linac Room

It is necessary to consider the effect of photoneutrons produced by photonuclear reactions in the shielding calculation of a medical linac room with incident electron greater than 10 MeV. For copper and tungsten used as the target materials of linac, we compared the experimental data with the eval-uated data in four photonuclear reaction files of photoneutron production cross sections. We also com pared the calculated results using four photonuclear files with experimental results on the angular distributions of photoneutrons emitted from targets bombarded by 18 and 28 MeV electrons. Conse-quently, we found that the shielding calculations by LA150 and JENDL / PD - 2016.1 gave the dose rates within a factor of 1.5 of accuracy in the electron energy of less than 28 MeV.