Nuclear or nucleonic level measurement devices can be employed in both point and continuous level detection applications. They are usually applied in fields where all other level measurement techniques fail to work owing to their capability of working with hazardous situations. In this method, energy needed for level measurement is emitted arbitrarily by radio isotopes in the form of bursts.
The major source utilized in nucleonic level controls includes gamma radiations. These are electromagnetic radiations which exhibit almost identical behavior to that of microwaves and light waves. However, they have comparatively higher energy and shorter wavelength owing to which these radiations are competent enough to break through the walls of process vessel and material.
The field strength of these gamma radiations is determined by a sensor mounted on the other end of the vessel, which ultimately detects the level of process material in the vessel. “Different radioisotopes are used, based on the penetrating power needed to “see” the process within the vessel. With single point gauges the radiation provides a simple on/off switching function, whereas with continuous level measurement the percentage of transmission decreases as the level increases.”