Dose mapping of the cobalt-60 source facility at the Secondary Standard Dosimetry Laboratory of Philippine Nuclear Research Institute

Abstract

Dose assessment of the facility containing the Co-60 teletherapy machine located at the Secondary Standard Dosimetry Laboratory (SSDL) of Philippine Nuclear Research Institute (PNRI) was made. From the measurements, a dose map was created and utilized to determine the required shielding requirement. When the unit is off, all doses measured were below the dose limitations for radiation workers and the public. A maximum dose rate of 10.70 μSv/h was recorded when the machine is OFF while a maximum dose rate of 29.90 μSv/h was obtained when the machine is ON. The wall thickness appropriate for the facility was calculated to be equal to 0.63 m. Results indicate that when the machine is OFF, it is not considered a threat to radiation workers and the public.