Abstract
Second order image aberrations are calculated for the famous double focusing mass spectrographs in the world. The influence of the fringing field is introduced as a transformation at the ideal field boundary. The focusing properties of the apparatus built at Minnesota, Manitoba, Osaka, Mainz, Argonne, Garching and Mattauch-Herzog instrument are discussed. The image aberrations due to the ion-beams of off median plane are found to be quite serious by the influence of the fringing field. The influence is also important if we want to correct the image defects. An example of the double focus ing mass spectrometer corrected for all six second order image defects is also shown.
