title: First participation by the NMISA in a low-level comparison: CCRI(II)-S9 exercise.
abstract: The NMISA Radioactivity Standards Laboratory participated in the CCRI(II)-S9 inter-comparison of the measurement of the activity concentration of (137)Cs and (40)K in rice material, piloted by the KRISS. The paper describes the equipment used, the measurement set-up and data analysis. The efficiency of the detector for (137)Cs and (40)K was determined by comparison against a spiked standard solution, and Monte Carlo simulations performed to estimate the difference in γ-ray escape probability between the solution standard and starch (as an approximation for milled rice) due to attenuation disparities. The uncertainty budget was estimated rather conservatively, since these were the first low-level measurements performed by the NMISA using an HPGe detector.
authors.affiliation: National Metrology Institute of South Africa, 15 Lower Hope Road, Rosebank, 7700 Cape Town, South Africa. fvwyngaardt@nmisa.org
authors.forename: W M
authors.initials: WM
authors.lastname: van Wyngaardt
authors.forename: M J
authors.initials: MJ
authors.lastname: van Staden
authors.forename: J
authors.initials: J
authors.lastname: Lubbe
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis* / Q000592:standards; D012275:Oryza / Q000737:chemistry*; D011197:Potassium Radioisotopes / Q000032:analysis* / Q000592:standards; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000592:standards*; D011848:Radioactive Pollutants / Q000032:analysis* / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013019:South Africa
chemical_list: D002588:Cesium Radioisotopes; D011197:Potassium Radioisotopes; D011848:Radioactive Pollutants
keywords: Cs-137; Inter-comparison; K-40; Low-level; Rice reference material