SPI Supplies Brand TEM Grids Asbestos Index 200 Mesh Copper Emicron Design Vial of 100 Grids
Diameter: 3 mm
Thickness: 0.4 mils / 10 µm
Grid Bar Widths:
Thick: 35 µm ± 5%
Thin : 21 µm ± 5%
Index Grid, Copper, "200 Mesh"
Vial (100 Grids)
This highly popular EMicron™ Brand TEM Asbestos Index Grid, featuring a "thick/thin" grid bar design, is in use in many of the world's busiest asbestos testing laboratories world wide. In this case the indexing is directly adjacent to each grid square but in that case, the total number of grid squares available for analysis, relative to the SPI Asbestos Index Grid, is cut roughly in half.
We do want to stress that this is the original EMicron asbestos index grid, with the perfectly smooth grid bars and the highly reproducible area, grid square to grid square.
Parallelism of the grid bars:
We can not measure any deviation at the low magnification light microscope level.
Dimension details about the pattern:
Width of the bars (e.g. lines) of the letters is roughly 14 µm, but it depends on the specific letter or number, and it does vary. But 14 µm is an "average" figure. Check out these features that have made these 200 mesh grids popular in my high volume TEM asbestos testing laboratories:
Alpha numeric indexing right next to the grid square being used:
Makes it even easier to identify and relocate specific grid squares for the mandated verification counting.
Grid squares are indeed square:
Consistent (almost imperceptible standard deviation) from square to square on all grids within a given batch. SPI uses its own SPI-Quant™ image analysis system to confirm that batch to batch, even grid to grid, variation is within our specifications.
Special "V" shaped notch on the rim:
Helps ensure that you always reinsert (for verification counting) the grid into the microscope using the same identical orientation. However this does not show you whether you have inserted the grid right side up. This is determined by the dull vs shinny side discrimination. If this is not sufficient for your own personal preferences, then we would recommend instead the SPI Asbestos Index Grid which has the asymmetric "SPI" in the rim.
Select from copper or nickel. For normal kinds of work, we would recommend copper although some analysts have expressed a preference for the stiffer physical properties of nickel.
Standard deviation of the area, square to squarer:
While not guaranteed, virtually all batches run better than 5%.