An Aerial Radiological Survey of Selected Areas of the City of North Las Vegas

Wasiolek, Piotr

National Security Technologies, LLC

关键词: Ground Level;    Global Positioning System;    Sodium Iodides;    Remote Sensing;    Energy Spectra;   

DOI  :  10.2172/933029
RP-ID  :  DOE/NV/25946--489
RP-ID  :  DE-AC52-06NA25946
RP-ID  :  933029

美国|英语

来源: UNT Digital Library

【 摘 要 】

As part of the proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory-Nellis (RSL-Nellis) conducted an aerial radiological survey of selected areas of the city of North Las Vegas for the purpose of mapping natural radiation background and locating any man-made radioactive sources. Survey areas were selected in collaboration with the City Manager's office and included four separate areas: (1) Las Vegas Motor Speedway (10.6 square miles); (2) North Las Vegas Downtown Area (9.2 square miles); (3) I-15 Industrial Corridor (7.4 square miles); and (4) Future site of University of Nevada Las Vegas campus (17.4 square miles). The survey was conducted in three phases: Phase 1 on December 11-12, 2007 (Areas 1 and 2), Phase 2 on February 28, 2008 (Area 3), and Phase 3 on March 19, 2008 (Area 4). The total completed survey covered a total of 44.6 square miles. The flight lines (without the turns) over the surveyed areas are presented in Figures 1, 2, 3, and 4. A total of eight 2.5-hour-long flights were performed at an altitude of 150 ft above ground level (AGL) with 300 feet of flight-line spacing. Water line and test line flights were conducted over the Lake Mead and Government Wash areas to ensure quality control of the data. The data were 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. Data, in the form of gamma energy spectra, were collected continually (every second) over the course of the survey and were geo-referenced using a differential Global Positioning System. Collection of spectral data allows the system to distinguish between ordinary fluctuations in natural background radiation levels and the signature produced by man-made radioisotopes. Spectral data can also be used to identify specific radioactive isotopes. As a courtesy service, with the approval of the U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office, RSL-Nellis is providing this summary to the office of the Mayor of the City of North Las Vegas along with the gross-count-based exposure rate and man-made count contour maps and GIS shape files in electronic format on a compact disk.