At both ends of the lens stack should be installed a pinhole (2D lenses) or a slit (1D lenses) in order to limit the incoming beam in its lateral extension and to reduce scattered radiation (Figure 1). The geometric aperture of the pinholes and the slits should be slightly smaller than the geometric aperture of the lenses. We offer suitable high-precision pinholes and slits for all lens types.
In Figure 2, the following notation is used: F thickness of the pinhole/slit, 2R0 width of the pinhole/slit, L length of the slit. A typical value for the thickness F is 1.2 mm for the pinholes and 2.4 mm for the slits. The length L of the slits usually is 2 mm.
Note that the slits consist of two components, allowing for an exactly rectangular cross section without rounded corners (Figure 2 right).