title: Electron contamination of large cobalt 60 photon beams.
abstract: Experimental results are presented of the electron contamination of cobalt 60 gamma photon beams from the Mobaltron MS80, over a range of SSD's from 60 cm to 3.5 m. In the absence of an electron filter, the skin dose can exceed the dose at 4 mm depth by up to 1.6 times due to the high level of electron emission from the depleted uranium collimators. 4 mm of perspex effectively removes these electrons, and in the filtered beam, the skin dose cannot exceed the 4 mm dose. The electron contamination of a 6 MV X-ray beam is compared.
mesh_terms: D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D004583:Electrons; D004601:Elementary Particles; D005374:Filtration; D006801:Humans; D011829:Radiation Dosage; D011867:Radioisotope Teletherapy; D012542:Scattering, Radiation; D012867:Skin / Q000528:radiation effects*
chemical_list: D003037:Cobalt Radioisotopes