Agar Scientific offers a large range of scanning electron microscope calibration standards. Some of these calibration standards are discussed in detail below.
Examples of Calibration Standards
Calibration standards offered by Agar Scientific include:
Gold on carbon AGS168 - resolution test specimen -This specimen has a particle size range from approximately 5 - 150nm. Each specimen has a square grid pattern with large crystals in the centre of each grid square and very fine crystals at the edges of each grid (as illustrated). Medium and high resolution point separation tests may be performed on the same specimen. In addition, the larger crystals show facets which allow an assessment of the grey level reproduction available at high resolution
Gold on carbon AGS1969 - high resolution test specimen-This specimen is particularly suitable for assessing the image quality of high resolution SEMs, such as those fitted with a field emission electron source. A magnification of at least x80,000 is required to clearly resolve the gold particles. Particle sizes range from <3 - 50nm.
Tin on carbon AGS1967 - resolution test specimen-An alternative test specimen for medium resolution evaluation and for the day-to-day visual checking of instrument performance is a tin on carbon specimen. This consists of a dispersion of tin spheres,within the size range 10 - 100nm, on a carbon substrate. Ideal for astigmatism correction, it is also recommended for use in SEMs employed in the semiconductor industry, where the usual gold on carbon sample cannot be used because of the risk of gold poisoning.
Tin on carbon AGS1988 - low voltage resolution test specimen- Similar to the AGS168Z specimen, this tin on carbon specimen with larger spheres is easier to use in low kV imaging mode and where gold on carbon may not be appropriate. The spherical nature of the balls makes them ideal for astigmatism assessment. Particle size range is from approximately <20 - 400nm.