title: Definition of source for head shielding requirements in linear accelerators may affect room shielding design.
abstract: Siemens Corporation defines the source of the Mevatron 20 linear accelerator as a line source approximately 2 m in length. Calculations for secondary barriers for leakage radiation are generally based on 0.1% of the useful beam 1 m from the target. The difference in source terms can lead to calculating thinner barriers than are required. The placement of a 30 X 10 X 10-cm block of lead behind the head was required to achieve acceptable radiation levels.
mesh_terms: D002140:California; D006257:Head; D006744:Hospital Bed Capacity, 100 to 299; D006748:Hospital Departments; D006801:Humans; D010315:Particle Accelerators / Q000592:standards*; D011835:Radiation Protection / Q000592:standards*; D011872:Radiology Department, Hospital