Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources {and detecting secondary Y-rays as well as reflected or back-scattered neutrons}
Prospecting or detecting by the use of nuclear radiation, e.g. of natural or induced radioactivity specially adapted for well-logging using primary nuclear radiation sources or X-rays using neutron sources {and detecting secondary Y-rays as well as reflected or back-scattered neutrons}