Agar Scientific has a wide range of high quality disc apertures and thin foil apertures for use in electron microscopes, and Focus Ion Beam, microprobe and X-ray systems. Disc apertures are manufactured to tight tolerances with precision drilled holes. They are usually made from a platinum/iridium alloy 95:5% or molybdenum, although tantalum can be supplied for some applications. Platinum apertures can be made with hole sizes down to 5μm diameter whereas the smallest size for molybdenum is 10μm. Agar thin film apertures are frequently used in the objective lenses of high resolution and electron beam lithography instruments. These apertures have the advantage that they heat up in the beam and are effectively self-cleaning. Agar apertures are made to exceptionally high standards and are only accepted after examination in the TEM to check the perfection of the edge of the hole, its roundness and absence of pin holes in the vicinity. We maintain a stock of all the regularly used aperture sizes with disc diameters and thicknesses to suit all current EM systems. We also have apertures for systems which are no longer manufactured but are still in use.