Correlation relations for estimating the content of plutonium isotopes in fallout due to the Chernobyl accident

The possibility of determining the total alpha activity A(Pu-239,Pu-240) of Pu-239 + Pu-240 according to the gamma radiation of Ru-103 and Ru-106 is examined. The statistical properties of the experimental ratios of the activities rho = A(Ru-106)/A(Ru-103) are investigated. The distribution of the experimental ratios is similar to the theoretical ratios for fuel and close to a Gaussian distribution with average value < p > = 0.22 and standard deviation Delta similar to 0.06. This ratio is used to obtain a relation for estimating A(Pu-239,Pu-240) from the gamma activity A(Ru-103). A theoretical analysis is made of the experimental data for the southern raions of Gomel oblast. It is shown that given a good statistical sample of measurements of the gamma activity of Ru-103 it is possible to estimate the average value of the gamma activity A(Pu-239,Pu-240) and with probability 0.95 the interval of the possible values of this activity.