Abstract :
Methods for liquid-flow measurement based on the transit time of a positron active source are described, and the accuracy of each method is estimated. A microprocessor-based system and a TTL integrator for studying a positron active flow is constructed. The theoretical and experimental studies show that the velocity of a point source, 111 kBq (3¿Ci) Na22-isotope (¿ 1 mm) inside a metal pipe (¿ 42 mm) can be measured using annihilation coincidence detection (detector pairs 1 m apart) and microprocessor electronics with inaccuracies of 0.2, 0.5, 0.7 percent for velocities 0.1, 0.5, and 1.0 m/s, respectively, at the 95 percent level of significance. Greater accuracy can be achieved by increasing the activity of the source.
