Charts for estimating the axial shielding factors of open-ended cylindrical shields

摘要

Axial shielding factors of single and double-shell open-ended cylindrical magnetic shields are calculated numerically and represented by charts. It is assumed that the thickness of the shells is small (1%) compared to the largest diameter and the permeability is independent of magnetic induction. Dependencies of the axial shielding factors on the shields' geometry and permeability are calculated numerically and represented finally as logarithmic-scale contour plots. Single-shell shields are described by one chart only where the length-to-diameter ratio (1 to 10) and the permeability (10/sup 1/ to 10/sup 4/) normalized to the thickness-to-diameter ratio are variable parameters. Double-shell shields are described by a set of charts where the ratio of the shells' lengths (0 to 1) and the normalized permeability are variable parameters while the outer shell length to diameter ratio (3, 4, and 5) and the ratio of the shells' diameters (0.5, 0.6...0.9) are fixed parameters.