Beryllium has long been recognized as the ideal material for grids for
analytical electron microscopy. The low atomic number of beryllium assures
the microscopist of EDS spectra which are both free from annoying
characteristic x-ray peaks and low in Bremsstrahlung background radiation.
SPI Supplies has switched to a new, higher purity beryllium metal than
previously for beryllium grid production, characteristic x-ray peaks from
impurities in the metal are virtually absent from grid bar control spectra.
These grids, which are all 25µm thick area available as both square mesh
and slot designs. Beryllium metal is difficult to etch, and these grids do
not have grid bars that are thin and smooth, or the large open areas of our
other grids made by electro deposited techniques.
Important note: Not all beryllium TEM grids are the same.
Because of the uniqueness of beryllium, and the safety concerns when the
metal is processed, there is not a large number of firms offering beryllium.
Indeed the number of such firms processing and refining beryllium metal in
the world could be counted on half the fingers of one hand. The leading
firm is, by far,
Brush Wellman Electrofusion.
Most beryllium fabricators use as their starting material high purity beryllium
rod, strip or foil that has been produced by Brush Wellman. We do have
available beryllium starting material from sources outside of the USA,
however the claimed purity is never as high as is claimed, and in any case,
fall far short of the purity specifications of the Brush Wellman supplied
material. The TEM grids being offered by SPI Supplies have been fabricated
from the highest purity available from Brush Wellman. We want to make that
point because there is just no comparison between these fine outstanding
grids produced from Brush Wellman starting material and grids produced from
material of alternative origins.
We would recommend anyone contemplating the use of beryllium should be
familiar with some basic concepts about beryllium and
the use of beryllium in the electron microscope laboratory.
All SPI Beryllium grids are 25µm thick. Packaged in a green dial-a-grid box.
SPI Supplies can now offer
"beryllium half grids".
The
SPI Supplies brand of silicon nitride membrane window grids
might be a better option for those wanting to do analytical TEM work without getting interference from the grid itself.
The silicon nitride (or silicon oxide) membrane is just too thin for any of the elements in the
membrane to be detected by EDS. In most TEMs, one sees only a faint
hint of Si probably from
the silicon frame of the grid.
* Available while supplies last