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 by the median plane of the air gap is a convex curve towards the exterior. One can correct this curvature by giving to the mechanical face an equal and opposite curvature; the approximation obtained with the aid of plane faces is sufficient. When the correction of the aberration of the second order necessitates the use of curved mechanical faces, the parasite effect must be considered in the of the CERN, the double curvature of the face leads to troublesome aberrations much stronger than the abberrations of the second order. In the ease where the mechanical faces are inclined by an angle alpha /sub o/ on the direction of the same trajectory ("vertical" focusing), the magnetic fronts have a weaker average inclination. The "drag" DELTA alpha increases very rapidly with alpha /sub o/, and causes a distortion of the magnetic faces. The correcectors, and for a given magnet a method of correction can generally be perfected for all used values of alpha /sub 0/. (trauth)
- Research Organization:
- European Council for Nuclear Research, Geneva
- NSA Number:
- NSA-13-009071
- OSTI ID:
- 4292014
- Report Number(s):
- CERN-59-1
- Country of Publication:
- Switzerland
- Language:
- English
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