Why are negative results reported for radiochemical measurements?
Measurements of radiochemical samples require that analytical or instrumental backgrounds be subtracted to obtain net values. Thus, the net values are sometimes obtained that are lower than the minimum detection limit of the analytical technique. Consequently, individual measurements can result in values of positive and negative numbers. Although a negative value does not represent a physical reality, a valid long-term average of many measurements can be only be obtained if the very small and negative numbers are included in the population calculations.
