A lamellar arrangement for shielding radiation acting on a fluid which flows through an interior of a device, comprises two or more lamellae aligned substantially parallel to one another and respectively defining an intermediate space between them, wherein at least one subset of the lamellae is respectively subdivided into at least three lamella sections comprising a first lamella section, a second lamella section next to the first lamella section and a third lamella section next to the second lamella section. The first lamella section and the second lamella section in this case enclose a first angle between them, and the second lamella section and the third lamella section enclose a second angle between them. The first angle has a magnitude in a range of from 20° to 45° and the second angle has a magnitude in a range of from 20° to 45°.