## The Leakage Field of Magnetic Deflectors. Shape of Magnetic Fronts, Correction of Aberrations; SUR LE CHAMP DE FUITE DES DEFLECTEURS MAGNETIQUES FORME DES FACES MAGNETIQUES, CORRECTION DES ABERRATIONS

The leakage fields of the extremities of the magnetic deflectors can be taken into account by defining an effective length d on the mean trajectory. In a magnet with pole pieces sufficiently large, the imaginary magnetic fronts of entry and outlet are planar in the useful zone because d is constant. However, the narrowing of the pole pieces causes the deformation of this front. in the case where the magnetic fronts are planar and normal to the direction of the mean trajectory, the magnetic fronts are curved and possess at each point two equal and opposed curvatures. Their section bymore »