High-sensitive radioactivity logging borehole instrument

The design of a well device in which the high sensitivity to the measured gamma radiation is achieved due to the efficient utilization of the useful internal volume is described; it permits to use standard scintillators of a larger size without changing the outer diameter of the instrument. The container of the scintillator is removed; white nitroenamel, which covers the surface of the scintillator , fulfils the function of a diffusive reflector. The protecting casing of the well device is designed in such a way that it can be shifted to the direction of the logging cable when it is necessary to open the electronic circuit. This well device was tested as one of the elements of the logging gamma-spectrometer at an uranium-thorium ore object and in a phlogopite deposit