PEDESTRIAN RADIATION PORTAL MONITOR
The PPM pedestrian radiation portal monitor has been designed to monitor persons passing through the device for detection of smuggled radioactive sources or possible contamination.
The system features a portal mechanical structure, with two columns on the sides of the measuring zone, each containing one plastic scintillator detector with a large sensitive area.
Both detectors are lead shielded in order to reduce the contribution from the environmental background radiation.
The measurement starts when the camera detects the passage of a person through the portal. The monitor measures the radioactivity level, subtracts the background contribution and compares the net result with a pre-set alarm threshold. All measured data and information about alarm and failure statuses are displayed by the software.
The background level is automatically determined by the monitor when no passage through the portal is occurring.
The acoustic-luminous beacon installed on the top of the portal indicates the status of the portal. An output is available to control external interlock devices, e.g. to forbid the passage in case of alarms.
All alarm and failure events are archived, including the event date/time, the measurement data and the current alarm threshold setting.