title: The air-kerma rate constant: application to air-kerma measurements for homeland security.
abstract: Air-kerma rate measurements from 57Co, 60Co, and 137Cs radioactive sources were performed. These measurements were motivated by the development of new sources at the National Institute of Standards and Technology (NIST) for radiological testing of equipment for homeland security applications. The testing of radiation detection equipment relies on knowing the values of the air-kerma rate for the radioactive sources at a fixed distance from the source. The air-kerma rate can be measured or alternatively estimated by using published values of the air-kerma rate constant. Although there are a large number of published values of the air-kerma rate constant for radionuclide sources based on theoretical calculations, strong disagreement is observed throughout the literature. Furthermore, most of the published values have no uncertainties assigned, and therefore their use for testing radiological equipment is limited. In this work we report experimentally-measured values of the air-kerma rate for three radionuclides with well defined source geometries and activities. The results are compared to estimates based on published values of the air-kerma rate constant. Such values are easily found in the literature from the last three decades and are used commonly by the scientific community.
authors.affiliation: National Institute of Standards and Technology, 100 Bureau Drive, Stop 8462, Gaithersburg, MD 20899-8462, USA. leticia.pibida@nist.gov
authors.forename: L
authors.initials: L
authors.lastname: Pibida
authors.forename: R
authors.initials: R
authors.lastname: Minniti
authors.forename: L
authors.initials: L
authors.lastname: Lucas
authors.forename: S M
authors.initials: SM
authors.lastname: Seltzer
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D002588:Cesium Radioisotopes / Q000032:analysis; D003037:Cobalt Radioisotopes / Q000032:analysis; D006207:Half-Life; D006801:Humans; D011835:Radiation Protection; D011868:Radioisotopes / Q000032:analysis*; D012637:Security Measures; D012680:Sensitivity and Specificity; D014481:United States
chemical_list: D000396:Air Pollutants, Radioactive; D002588:Cesium Radioisotopes; D003037:Cobalt Radioisotopes; D011868:Radioisotopes