Application of Tagged Neutron Method for Element Analysis of Phosphorus Ore

Abstract

The results of testing of AGP-F analyser based on the tagged neutron method on the phosphorus ores of the Kovdor deposit are presented. The tagged neutron method (TNM) consists in irradiating the ore with fast neutrons with energy of 14 MeV and recording the characteristic radiation of gamma quanta from reactions of inelastic neutron scattering in certain time intervals between the emission of a neutron and the arrival of a signal from a gamma quantum. Unique possibility of TNM is information about time between signals from α- and γ-detectors. It allows selecting γ-rays coming only form the object under study. Using TNM allows increasing signal/background ratio by factor 200. Another advantage of TNM in comparison with other methods of ore express analysis is high penetration ability of 14 MeV neutrons. The experimental setup consists of neutron generator with 9 α-channels and 12 γ-detectors. It allows determining the elemental composition of ore in the field conditions without any sample preparation. The tests show that for moisture of the sample up to 20% the difference between results of dry and wet sample analysis does not exceed the reproducibility limit. The reason is the possibility to determine concentration of oxygen that is provided by TNM. It is possible to measure the large samples of 1-2 kg with accuracy, reasonable for the field measurements, in 10-15 minutes.