A time‐resolved measurement of an impulsive ion source has been carried out by developing a detector consisting of a magnetic energy analyzer and a microchannel plate (MCP) with multianodes. A method to calibrate the electron multiplication factor of the MCP for charged particles using a solid‐state nuclear track detector (SSNTD) is presented. The method has been successfully used for the energy analysis of the deuteron beam produced by the plasma focus. The method is applicable not only for deuterons but also for any other energetic charged particles.