Strontium-90 measurement after the Chernobyl accident in Romanian samples without chemical separation

This paper presents a method for measuring 90Sr from soil and sediments without a preliminary chemical separation of strontium from samples. The measurements were done using a Geiger–Müller proportional radiation detector of VA-Z-520 type, an RFT-20026 monochannel analyser and aluminium plates of two thicknesses determined in this way to select the 1500–2281-keV energy range for the 90Y measurement and to avoid the 106Rh interference. The results obtained with this method were compared with those using chemical separation. This method was used to determine the strontium content in four samples, which were collected in Cluj-Napoca and three other Romanian towns (Transylvania region) after the Chernobyl disaster. The obtained values for these samples are in the 40–75-Bq/g range for 90Sr. The 90Sr/137Cs ratio is approximately 1:8, close to the ratio 1:10 determined in samples from Bucharest area and Japanese samples measured during 1988.