SPI Line Grating Replica for TEM Magnification Calibration, on 3 mm Copper Grid
The SPI Supplies brand waffle and parallel line style resolution checker samples are useful for high magnification calibration of any TEM or STEM. We offer two types of grating replicas: (a) line spacing, and (b) waffle (cross line) spacing. Both types have a spacing of 2160 lines per mm (54,800 lines per inch). The carbon replicas are gold/palladium shadowed for enhanced contrast. Both samples are supplied supported on a 3.05mm diameter 300 mesh copper grid. For the ultimate TEM calibration sample, consider the Mag*I*Cal™ TEM Calibration Test Sample.
Line Grating Replica
Some other considerations when using this sample:
It surely would seem that most things involving electron microscopy are a bit more complicated than they at first appear. When doing TEM magnifications calibrations, one must be aware of hysteresis effects. But this is not the only concern one must have when using this type of calibration grid: We are talking about grid "sag", that is the tendency of the replica film (or any TEM sample for that matter) to "sag" as it is stretched across the grid opening. This sag becomes more pronounced as the hole size becomes larger (e.g. smaller number of the grid mesh size). One can minimize the grid sag by requesting a calibration grating on a higher grid mesh (e.g. smaller hole size). One can also increase the accuracy of their spatial measurements by mounting their samples on grids of smaller hole size. The ultimate grid of this type would be the SPI Silicon Nitride Membrane Window grids, because in that case, there is zero grid sag and one would have the best possibilities of achieving both the highest accuracy and precision in their measurements.