title: Shielded and unshielded geometries in the search for orphan sources.
abstract: A car-borne NaI(Tl) spectrometric system was used together with a 137Cs source to obtain realistic data in the search for unshielded and semi-shielded orphan sources. The potassium-stripped counts (PSC) method was used to estimate the influence by the shielding on the detection ability. A reduction of about 5% in the critical distance was obtained for the semi-shielded source. A curve fitting method was also developed and evaluated. Results from the curve fitting method showed inferior ability to find the source compared to the PSC method. However, it can be a useful complementary tool, for characterisation of the source shielding, and estimation of the distance from the road.
authors.affiliation: Department of Medical Radiation Physics, Clinical Sciences, Lund, Lund University, University Hospital, SE-221 85 Lund, Sweden. Thomas.Hjerpe@sroy.fi
authors.forename: Thomas
authors.initials: T
authors.lastname: Hjerpe
authors.forename: Christer
authors.initials: C
authors.lastname: Samuelsson
mesh_terms: D002588:Cesium Radioisotopes / Q000737:chemistry; D011834:Radiation Monitoring / Q000379:methods*; D011848:Radioactive Pollutants / Q000032:analysis*; D012044:Regression Analysis; D013051:Spectrometry, Gamma / Q000379:methods*
chemical_list: D002588:Cesium Radioisotopes; D011848:Radioactive Pollutants