title: Scan MDCs for GPS-Based Gamma Radiation Surveys.
abstract: A method for estimating the minimum detectable concentration of a contaminant radionuclide in soil when scanning with gamma radiation detectors (known as the "scan MDC") is described in the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM). This paper presents an alternate method for estimating scan MDCs for GPS-based gamma surveys based on detector efficiencies modeled with the probabilistic Monte Carlo N-Particle Extended (MCNPX) Transport simulation code. Results are compared to those provided in MARSSIM. An extensive database of MCNPX-based detection efficiencies has been developed to represent a variety of gamma survey applications and potential scanning configurations (detector size, scan height, size of contaminated soil volume, etc.), and an associated web-based user interface has been developed to provide survey designers and regulators with access to a reasonably wide range of calculated scan MDC values for survey planning purposes.
authors.affiliation: *Environmental Restoration Group, Inc. (ERG), 8809 Washington St. NE, Suite 150, Albuquerque, NM 87113.
authors.forename: Tyler
authors.initials: T
authors.lastname: Alecksen
authors.forename: Randy
authors.initials: R
authors.lastname: Whicker
mesh_terms: D003198:Computer Simulation; D004784:Environmental Monitoring / Q000379:methods*; D005720:Gamma Rays; D040362:Geographic Information Systems; D015233:Models, Statistical; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods*; D011868:Radioisotopes / Q000032:analysis* / Q000145:classification; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive