Yeltepe, EminŞahin, Namık KemalAslan, NazifeHult, MikaelÖzçayan, GültenWershofen, HerbertYücel, Ülkü2018-03-282018-03-282018-04Yeltepe, E., Şahin, N.K., Aslan, N., Hult, M, Özçayan, G., Wershofen, H. ve Yücel, Ü. (2017). Applied Radiation and Isotopes. Volume 134, April 2018, pages 40-44.0969-8043http://kurumsalarsiv.tenmak.gov.tr/handle/20.500.12878/633A proficiency test amongst 15 Turkish laboratories with participation of 5 non-Turkish laboratories was organized to determine the 137Cs, 40K and 90Sr massic activities in black tea powder samples. The bulk material, consisting of tea produced in 2014, was mixed with contaminated tea that was withdrawn from the market after the Chernobyl accident. Nineteen laboratories reported 41 results. The evaluation of the results was based on the accuracy and precision criteria adopted by the IAEA Proficiency Testing Group and resulted in 49% acceptable results, 19% acceptable with warning and 32% were found to be not acceptable.enginfo:eu-repo/semantics/embargoedAccessRadioactivity in tea powderÇay tozunda radyoaktiviteEnvironmental gamma ray spectrometryGama spektrometriRadioactivity proficiency testRadyoaktivite yeterlilik testi226Ra, 40K, 90Sr measurements226Ra, 40K, 90Sr ölçümleriarticle1344044