title: Monte Carlo study of a 60Co calibration field of the Dosimetry Laboratory Seibersdorf.
abstract: The gamma radiation fields of the reference irradiation facility of the Dosimetry Laboratory Seibersdorf with collimated beam geometry are used for calibrating radiation protection dosemeters. A close-to-reality simulation model of the facility including the complex geometry of a 60Co source was set up using the Monte Carlo code MCNP. The goal of this study is to characterise the radionuclide gamma calibration field and resulting air-kerma distributions inside the measurement hall with a total of 20 m in length. For the whole range of source-detector-distances (SDD) along the central beam axis, simulated and measured relative air-kerma values are within +/-0.6%. Influences on the accuracy of the simulation results are investigated, including e.g., source mass density effects or detector volume dependencies. A constant scatter contribution from the lead ring-collimator of approximately 1% and an increasing scatter contribution from the concrete floor for distances above 7 m are identified, resulting in a total air-kerma scatter contribution below 5%, which is in accordance to the ISO 4037-1 recommendations.
authors.affiliation: Health Physics Division, ARC Seibersdorf research GmbH 2444 Seibersdorf, Austria. christian.hranitzky@arcs.ac.at
authors.forename: C
authors.initials: C
authors.lastname: Hranitzky
authors.forename: H
authors.initials: H
authors.lastname: Stadtmann
mesh_terms: D000465:Algorithms; D001317:Austria; D001822:Body Burden; D002138:Calibration; D003037:Cobalt Radioisotopes / Q000032:analysis* / Q000592:standards*; D003198:Computer Simulation; D038622:Internationality; D007753:Laboratories; D008954:Models, Biological; D015233:Models, Statistical; D009010:Monte Carlo Method; D016273:Occupational Exposure / Q000032:analysis* / Q000517:prevention & control; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D011835:Radiation Protection / Q000379:methods / Q000592:standards; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012680:Sensitivity and Specificity; D012984:Software
chemical_list: D003037:Cobalt Radioisotopes