The current density for thin shields is shown in Figure 3. The current density
in thick shields is the same as for thin shields. A secondary reflection
occurs at the far side of the shield for all thicknesses. The only difference
with thin shields is that a large part of the re-reflected wave may appear on the front surface. This wave can add to or subtract from the primary reflected wave depending upon the
phase relationship between them. For this reason, a correction factor appears in the shielding calculations to account for reflections from the far surface of a thin shield.