Detection of positive ions in an air cylindrical detector with a negatively charged wire

A new method for detecting positive ions in ambient air was developed. A cylindrical ionization detector with a negatively charged wire, operating in the limited gas amplification mode, was used. The distributions of electric-pulse heights due to positive ions were measured at various voltages between the electrodes. The physical processes inside the detector were studied. The method was used to measure the positive-ion concentration in ambient air. The experimental model of the instrument made it possible to determine the concentrations of positive ions with 1–10−3-cm2/(V·s) mobilities in a range of 102–104 cm−3. Other possible applications of the single-ion detection technique were considered.