Cerberus Nuclear provided support to the preliminary bulk shielding design of a new cyclotron facility intended for activation of radium targets for medical purposes. This work required a multi-stage process, utilising PHITS to generate neutron and gamma source terms for the proton beam from the cyclotron, both directly impacting a concrete shield wall and hitting the copper backed radium target.
MCNP was utilised to perform a number of shielding calculations to determine the appropriate concrete shield wall thicknesses in order to meet regulatory requirements. The proton beam was assessed impacting both the wall directly and the copper backed radium target. Additionally, the shielding requirements for the activated radium target were determined for concrete, steel and lead glass, to represent a number of processing steps that these targets will undergo after activation. PHITS was utilised to provide an independent cross-check of these shielding calculations.