title: Calibration of monitors used for surveillance of radioactivity in effluent water from CERN's accelerator installations.
abstract: Water released into the environment from CERN's accelerator installations may contain both long-lived (7Be, 22Na) and short-lived (11C, 13N, 24Na) gamma radioactivity. Each potential release point is equipped with an on-line monitor for short-lived radionuclides, which consists of a scintillation probe immersed in a tank filled with monitored water. Whilst calibration standards are available for long-lived radioactivity, computer simulations are the only feasible way to determine the monitor efficiency for the short-lived radionuclides. The paper describes computer simulations using the Monte Carlo code GEANT 3.21. An excellent agreement between measured and computed efficiencies was obtained for the long-lived radionuclides, validating the computer model. A calibration method is proposed for light positron emitters, which combines an experimental calibration for 7Be and correction factors obtained in the simulations.
authors.affiliation: CERN, European Organization for Nuclear Research, TIS Division, Geneva, Switzerland. pavol.vojtyla@cern.ch
authors.forename: P
authors.initials: P
authors.lastname: Vojtyla
mesh_terms: D000465:Algorithms; D001608:Beryllium / Q000032:analysis; D002250:Carbon Radioisotopes / Q000032:analysis; D003198:Computer Simulation; D004787:Environmental Pollution / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis; D011834:Radiation Monitoring / Q000379:methods*; D011847:Radioactive Fallout / Q000032:analysis*; D011868:Radioisotopes / Q000032:analysis*; D012964:Sodium / Q000032:analysis; D013057:Spectrum Analysis; D014867:Water / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002250:Carbon Radioisotopes; D011847:Radioactive Fallout; D011868:Radioisotopes; D014875:Water Pollutants, Radioactive; D014867:Water; D012964:Sodium; D009584:Nitrogen; D001608:Beryllium