Open AccessA magnet model for a hybrid undulator assembly
Author(s) -
Ryynänen Matti
Publication year - 1998
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049597013034
Subject(s) - magnet , undulator , block (permutation group theory) , physics , flux (metallurgy) , optics , computational physics , materials science , geometry , mathematics , laser , quantum mechanics , metallurgy
A modelling method, in which a single magnet block is divided into several sub‐blocks, is described. It is assumed that each sub‐block is polarized homogeneously. The sub‐block polarizations are derived with a genetic algorithm, which analytically calculates the total magnet flux density values generated by all sub‐blocks and fits it to the values measured at the corresponding points in the vicinity of the magnet. The sub‐block modellings accomplished show notable improvement in predicting the magnet flux density within the undulator gap when compared with a model based on homogeneously polarized blocks. The sub‐block model can also be used when discarding bad magnets from a set. Finally, the results show that the inhomogeneities in individual magnets are one of the major reasons for poor predictability of the undulator field in hybrid devices.