Neutron gauges for acid concentration measurements in industrial installations

The principle of operation and more important parameters of neutron gauges for measuring acid concentration of sulphuric acid proved to be reliable and satisfactory during a few years operation in industrial installations. Their utilization to measure concentration of other acids such as hydrofluoric acid and boric acid, as well as to measure concentration of chlorine in water solutions was checked in laboratory or in experimental installations. The measuring heads of the gauges employ transmission geometry or immersed geometry of measurement. The gauges in transmission geometry are bolted onto the pipe containing the measured acid. In submersion geometry, the measuring head consists of a flow tank inside of which fast neutron source and thermal neutron detector are placed. The gauges can also be used to measure concentration of other acids, anywhere variation of acid concentration is accompanied by variation of concentration of hydrogen atoms in the solution. They can also be used to measure content of elements strongly absorbing thermal neutrons such as: Li, Cd, Rh, In, Gd and Pa and others. (author)