Development of a compact single ion microprobe

A compact single ion microprobe has been developed for the examination of the microscopic characteristics of sensors, particle detectors and other devices used for fusion diagnostic systems. The microprobe has been constructed by use of commercially available standard components and can be easily recomposed according to beam requirements for various irradiation experiments. The beam size and position were successfully measured by use of a beam sensor with a quadrant-type electrode. Furthermore, the automatic beam control and adjustment were accomplished by a feedback system in obedience to a computer program based on a modified SIMPLEX iterative method. Some experiments for the examination of the performance of the microprobe were done by use of several elaborate beam detectors and indicated that a beam of a single ion (one ion in one pulse), 1 ns in pulse width and 2.5 μm in diameter could be successfully produced by the present microprobe.