As proficiency training for the Remote Sensing Laboratory's (RSL) Aerial Measuring System (AMS) radiological mapping mission, a survey team from RSL-Nellis conducted aerial radiological surveys of the Las Vegas Strip and adjacent areas on four separate occasions. The dates of the surveys were: December 11, 2006; December 26, 2007; December 31, 2007; and July 1, 2008. The AMS operation and appropriate law enforcement agencies selected the survey area as an appropriate urban location in which to exercise the AMS capability for mapping environmental radiation and searching for man-made radioactive sources. The surveys covered approximately 11 square miles. Each survey required a 2.5 hour-long flight, performed at an altitude of 300 ft above ground level (AGL), at a line spacing of 600 ft. Water line and test line flights were conducted over the Lake Mead and Government Wash areas in order to quantify the non-terrestrial background contributed by the aircraft, radon, and cosmic activity, and in order to determine the altitude-dependent air mass correction. The gamma data was collected by the AMS data acquisition system (REDAR V) using an array of twelve 2-inch x 4-inch x 16-inch sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. One second gamma-energy spectral data were recorded continuously while in flight. This spectral data allows the system to distinguish between natural terrestrial background contributions and man-made radioisotope contributions. Spectral data can also be used to identify specific man-made radioactive isotopes. Data geo-locations were determined with a Real-Time Differential Global Positioning System (RDGPS).
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