New counting system for detection of charged particles: application to ions generated by a pulsed laser beam

A new counting system for charged particles, which is suitable for the counting of pulse trains arriving in a short time, was constructed. The system is composed of a microchannel-plate intensifier, a CCD camera, a frame buffer, a particle counter, and a personal computer. Ion (or electron) pulses incident on the microchannel plate are amplified and then converted to photoradiating spots on a fluorescent screen. The image of the bright spots on the screen is taken by the camera and stored in the frame buffer. The computer processes the stored data and counts the number of bright spots. The performance of the system was examined by applying it to the detection of ions generated by a pulse laser. More than 300 photoions generated by one laser pulse (pulse width: 30 ns) were successfully counted, indicating that the peak counting rate of the system exceeds 10¹⁰ cps.