Calibration of Marinelli vessels for measurement of radioactive environmental samples

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 385; no. 2; pp. 376 - 380
• Main Authors: Lavi, N., Alfassi, Z.B., Drndarski, N.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 21.01.1997
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(96)01042-X

In order to measure low-activity radioactive environmental samples, both in liquid and solid phases, the use of Marinelli (reentrant) beakers is recommended. Standards were prepared by mixing of standardized radioactive solutions with CaCO 3 of density 1.1 to 1.3 g cm −3, similar to densities of environmental samples. Measurements of calibrated Marinelli comparator standards on detector surface showed that the dependence of log Eff vs. log E is almost linear in the 120 keV to 1500 keV range. The data can be fitted more accurately by assuming a parabolic correlation (log Eff vs. log E). The validity of these standards was checked by determining the concentration of radio-europium, radio-cesium and 226Ra in three certified reference standard materials. The results obtained agreed well with the published certified data. The limit of detection for the determination of radio-cesium by γ-ray spectrometry under the prevailing experimental conditions is 0.1 Bq (2.7 pCi), for 0.5 kg of environmental samples.