PROMPT GAMMA NEUTRON ACTIVATION PROBE The neutron activation probe uses a source of neutrons instead of a gamma ray source and this gives greater depths of penetration than the gamma-gamma tool. It is a powerful tool which can provide specific information in a wide range of applications. The probe is useful for the following applications: delineation of ore body contacts coal ash determination ore grade Examples of specific information: percentage iron in iron ore ash content, percentage aluminum, percentage silica, percentage iron, and density in coal seams.