A multichannel mass and energy analyzer using crossed electric and magnetic fields for ion separation has been constructed to analyze plasmas produced in conjunction with a magnetic mirror machine. Ions are piped between the strong magnetic field of the mirror machine and the weaker magnetic field of the analyzer by auxiliary magnetic coils, and they enter the analyzer traveling in a direction nearly parallel to the magnetic field. There, the ions are accelerated by the electric field and assume cycloid‐like trajectories in the plane perpendicular to the magnetic field. The ions are collected by detectors located at the top of the cycloid. The amplitude of the cycloid is determined by thee/mof the ion; the distance traversed parallel to the magnetic field before collection is proportional to the velocity of the ion.