TY - JOUR

T1 - A new estimation of the axial shielding factors for multishell cylindrical shields

AU - Paperno, Eugene

AU - Koide, Hiroyuki

AU - Sasada, Ichiro

PY - 2000/5/1

Y1 - 2000/5/1

N2 - A new, more accurate formula describing double and multiple-shell axial magnetic shielding is obtained as a result of numerical verification of existing estimations. A standard ANSYS® software package was used. Parameters of the numerical model are as follows. Two concentric, closed cylinders of equal thickness and constant permeability are considered. The thickness-to-diameter ratio of the outer cylinder is t/D2 = 1/100, its length-to-diameter ratio varies as L2/D2 = 3, 4, and 5, the ratio of the cylinders' outer diameters varies as D1/D2 = 0.5, 0.6, 0.7, 0.8, and 0.9, a range of the ratio of the cylinders' lengths is L1/L2 = 0.1-0.9, and a range of the relative permeability is μ = 103-106. A significant disagreement between the existing estimations and between each of them and the numerical model is found. One of the examined algorithms is modified to improve its precision. A remarkable improvement in the accuracy of the new algorithm compared to both existing methods is achieved. On a basis of the new algorithm, a new formula describing multishell axial magnetic shielding is suggested.

AB - A new, more accurate formula describing double and multiple-shell axial magnetic shielding is obtained as a result of numerical verification of existing estimations. A standard ANSYS® software package was used. Parameters of the numerical model are as follows. Two concentric, closed cylinders of equal thickness and constant permeability are considered. The thickness-to-diameter ratio of the outer cylinder is t/D2 = 1/100, its length-to-diameter ratio varies as L2/D2 = 3, 4, and 5, the ratio of the cylinders' outer diameters varies as D1/D2 = 0.5, 0.6, 0.7, 0.8, and 0.9, a range of the ratio of the cylinders' lengths is L1/L2 = 0.1-0.9, and a range of the relative permeability is μ = 103-106. A significant disagreement between the existing estimations and between each of them and the numerical model is found. One of the examined algorithms is modified to improve its precision. A remarkable improvement in the accuracy of the new algorithm compared to both existing methods is achieved. On a basis of the new algorithm, a new formula describing multishell axial magnetic shielding is suggested.

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M3 - Article

AN - SCOPUS:0000920608

VL - 87

SP - 5959

EP - 5961

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 9 III

ER -