title: Gis predictive mapping of terrestrial gamma radiation in the Northern State, Sudan.
abstract: This study presents the evaluation of absorbed dose in air due to gamma-emitting nuclides from (238)U and (232)Th series, (40)K and (137)Cs and the corresponding geographical information system (GIS) predictive mapping for the Northern State. Activity concentration of (238)U, (232)Th , (40)K and (137)Cs in soil samples collected from different locations have been measured using high-resolution gamma spectrometry. On  average, activity concentrations were 19±4 ((238)U), 47±11 ((232)Th), 317±65 ((40)K) and 2.26 Bq kg(-1) for (137)Cs. Absorbed dose rate in air at a height of 1 m above ground surface was calculated using seven sets of dose rate conversion factors (DRCFs) and the corresponding annual effective dose was estimated. On average, the values obtained fall within a narrow range of 44 and 53 nGy h(-1), indicating that the variation in absorbed dose rate is insignificant for different DRCFs. The corresponding annual effective dose ranged from 53 to 65 µSv y(-1). Using GIS, prediction maps for concentrations of (238)U, (232)Th, (40)K and (137)Cs were produced. Also, a map for absorbed dose rate in air at a height of 1 m above the ground level was produced, which showed a trend of increasing from the west towards south-east of the State.
authors.affiliation: Sudan Atomic Energy Commission, PO Box 3001, Khartoum, Sudan. enashamed@yahoo.com
authors.forename: E
authors.initials: E
authors.lastname: Hamed Bashier
authors.forename: I
authors.initials: I
authors.lastname: Salih
authors.forename: A
authors.initials: A
authors.lastname: Khatir Sam
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D001417:Background Radiation; D002588:Cesium Radioisotopes / Q000032:analysis; D005720:Gamma Rays; D040362:Geographic Information Systems; D011197:Potassium Radioisotopes / Q000032:analysis; D011834:Radiation Monitoring; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013397:Sudan; D013910:Thorium / Q000032:analysis; D014501:Uranium / Q000032:analysis
chemical_list: D000396:Air Pollutants, Radioactive; D002588:Cesium Radioisotopes; D011197:Potassium Radioisotopes; D012990:Soil Pollutants, Radioactive; D014501:Uranium; D013910:Thorium