A single-ion monitor based on coincident measurement of secondary electrons for single event effect research

Single-ion monitoring is a key requirement for many energetic heavy-ion experiments, e.g., the laboratory simulation of the single event effect of semiconductor devices under heavy ion bombardments. We have developed a two-dimensional position-sensitive and timing monitor of individual ions. It is composed of a thin aluminum foil, a pair of microchannel plate detectors, and electrostatic and magnetic fields. When energetic heavy ions pass through the aluminum foil, secondary electrons generated on each side of the foil are guided by the fields to the corresponding detector. Both the hitting position and the arrival time of the secondary electrons on corresponding detectors are measured in coincidence. A test with an ²⁴¹Am α source shows that the present monitor is capable of discriminating true events from heavy background radiations. A position resolution of 1.0 mm and a recording time resolution of 50 ns have been realized in the test.