Neutron activation logging for fluorine (NAL - N16)

The main points of logging for fluorine based on the P-19(n,a)N-16 reaction are considered. From the results of model and in-situ borehole measurements the effects of changes in the element content and moisture of rocks and ores have been estimated. It is shown that the effect of element content can be neglected; an increase in volume moisture in a 100-mm-diam dry borehole by 10% results in a decrease in the gamma radiation intensity of N-16 (Isub(N-16)) by at most 4-5%. With the density variations of 2.75+-0.25 g/cm3 observed in fluorine beating ore deposits, Isub(N-16) varies by at most 7.5%. Its value depends most essentially on the diameter of the borehole. Isub(N-16) dependence diagrams are given for various borehole conditions and detector dimensions