Investigation of a density measurement technique using positron radiation

A density measurement technique, appropriate for the determination of average densities ranging from 10 to 100 kg/m3, is described. It can be applied for determining the density of foams or the humidity of pressurized gases. The technique makes use of the density dependent positron range in the measured matter. The used coincidence detection technique known from positron emission tomography, benefits from the back to back emitted annihilation quanta to determine the region of emission. A tailored detector system was checked in experiments with solid foam blocks and is ready for applications now.