title: Source terms, shielding calculations and soil activation for a medical cyclotron.
abstract: Calculations of the shielding and estimates of soil activation for a medical cyclotron are presented in this work. Based on the neutron source term from the18O(p,n)18F reaction produced by a 28 MeV proton beam, neutron and gamma dose rates outside the building were estimated with the Monte Carlo code MCNP6 (Goorley et al 2012 Nucl. Technol. 180 298-315). The neutron source term was calculated with the MCNP6 code and FLUKA (Ferrari et al 2005 INFN/TC_05/11, SLAC-R-773) code as well as with supplied data by the manufacturer. MCNP and FLUKA calculations yielded comparable results, while the neutron yield obtained using the manufacturer-supplied information is about a factor of 5 smaller. The difference is attributed to the missing channels in the manufacturer-supplied neutron source terms which considers only the18O(p,n)18F reaction, whereas the MCNP and FLUKA calculations include additional neutron reaction channels. Soil activation was performed using the FLUKA code. The estimated dose rate based on MCNP6 calculations in the public area is about 0.035 µSv h-1and thus significantly below the reference value of 0.5 µSv h-1(2011 Strahlenschutzverordnung, 9 Auflage vom 01.11.2011, Bundesanzeiger Verlag). After 5 years of continuous beam operation and a subsequent decay time of 30 d, the activity concentration of the soil is about 0.34 Bq g-1.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Postfach 510119, 01314 Dresden, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Konheiser
authors.forename: B
authors.initials: B
authors.lastname: Naumann
authors.forename: A
authors.initials: A
authors.lastname: Ferrari
authors.forename: C
authors.initials: C
authors.lastname: Brachem
authors.forename: S E
authors.initials: SE
authors.lastname: Müller
mesh_terms: D017357:Cyclotrons; D006801:Humans; D009010:Monte Carlo Method; D009502:Neutrons; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D019275:Radiopharmaceuticals; D012987:Soil
chemical_list: D019275:Radiopharmaceuticals; D012987:Soil