Measurement and modelling of radioxenon plumes in the Ottawa Valley

North Korean nuclear test of October 9th, 2006: The utilization of health Canada’s radionuclide monitoring network and environment Canada’s atmospheric transport and dispersion modelling

“…RPB's responsibilities include nuclear verification, incident monitoring, and an active role as a member of the Comprehensive nuclear-Test-Ban Treaty (CTBT). To facilitate these roles, Health Canada maintains radiation detector networks across Canada, one of which consists of NaI(Tl) detectors [1] that measure the pulse height of gamma rays from radioactive noble gases and then converts these spectra into measured values for air KERMA rate. The operation and calibration of these detectors have been described by Grasty [2,3].…”

Monte Carlo simulations of semi-infinite clouds of radioactive noble gases

“…RPB's responsibilities include nuclear verification, incident monitoring, and an active role as a member of the Comprehensive nuclear-Test-Ban Treaty (CTBT). To facilitate these roles, Health Canada maintains radiation detector networks across Canada, one of which consists of NaI(Tl) detectors [1] that measure the pulse height of gamma rays from radioactive noble gases and then converts these spectra into measured values for air KERMA rate. The operation and calibration of these detectors have been described by Grasty [5,6].…”

“…This apparent discrepancy has been resolved [4] and our techniques have been used to simulate other interesting radioactive noble gases ( 131 Xe, 133m Xe, 85 Kr, 85m Kr, 135 Xe). Greater accuracy in the air KERMA rate to activity concentration conversion value will assist meteorological modellers in verifying their atmospheric transport models [1]. In the event of an emergency, Environment Canada and other meteorological modelers will be able to model the movement of a radioactive cloud from the air KERMA value measured by Health Canada's NaI(Tl) network.…”

“…Health Canada maintains detector networks across Canada. One of these networks consists of NaI(Tl) detectors that measure air KERMA [1]. Located beside the NaI(Tl) detector in Ottawa is a radioxenon analyzer [2] that measures the activity concentration of 131m,133m,133,135 Xe directly.…”

“…However, on various dates, the two detectors in Ottawa reported a conversion value of 2.6 ± 0.2 pGy/hr per Bq/m 3 ; we have resolved this discrepancy [4] and have expanded on the study of other isotopes by focusing on the NaI(Tl) detector. Greater accuracy in the conversion value between the air KERMA and activity concentration will assist meteorological modellers in verifying their models [1]. Two Monte Carlo methods were used in this investigation.…”