A probabilistic description of radioactive contamination: a multivariate model

• Published in: Applied radiation and isotopes Vol. 54; no. 2; pp. 355 - 363
• Main Authors: Nikulin, M.S., Novak, M.M., Smirnov, T.I., Voinov, V.G., Krasnov, G.I.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2001
• Subjects: Environmental radioactive pollution; Gamma Rays - adverse effects; Gamma-ray spectrometry; Humans; Kazakhstan; Maximum likelihood and unbiased estimators; Models, Statistical; Multivariate Analysis; Multivariate discrete probability distributions; Nuclear Warfare; Radioactive Fallout - adverse effects; Radioactive Fallout - analysis; Safety; Spectrometry, Gamma; Kazakhstan; Multivariate discrete probability distributions; Gamma-ray spectrometry; Maximum likelihood and unbiased estimators; Environmental radioactive pollution
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/S0969-8043(00)00191-3

A multivariate discrete probability model is used to facilitate the description of gamma-ray spectroscopic data obtained from radioactively contaminated territory, east of the former Semipalatinsk nuclear test site in Kazakhstan. Two possible estimators of probabilities of interest have been considered: maximum likelihood and unbiased estimators. We show that unbiased estimators are much easier to compute. The model was used in two variants: (i) several radionuclides in spatially independent measurements, (ii) a single radionuclide in spatially dependent measurements. We show that, in both cases, it is important to take into account the correlation for the accurate evaluation of probabilities of interest.