TEM-EDX Calibration Specimens

FOR THE TEM-EDX CALIBRATION SPECIMENS PLEASE ASK THE OFFER FOR YOUR PARTICULAR CHOICE (SEE TABLES BELOW)

Many Transmission Electron Microscopes and Scanning Transmission Electron Microscopes are interfaced to energy dispersive X-ray (EDX) detectors and are used routinely to carry out quantitative and qualitative microanalysis.
MAC now have available uniformly thin (~600°A) Cu films which are carbon coated on both sides mounted on Al grids: they give consistent K:L ratios over the whole specimen.
Typical data taken from different specimen regions is shown in the table for a specific EDX system. Cu Ka and Cu La intensities and their ratios are given, and it can be seen that the ratio is sensibly constant. The spectra can be obtained without fully focusing the electron probe so the risk of contaminating the sample is small. The carbon coating limits the rate of oxidation of the samples and they can be kept for many months in a vacuum desiccator. The ratio of Cu K:Cu L has also been measured on specimens made at very different times and the values lie within the range shown in the table. The absolute value will of course be different for different EDX systems.
The calculated influence on the Cu K/Cu L ratio, of contamination (taken to be carbon) on the Be window, is modelled, together with the change in detector efficiency for the Cu K and Cu L, which is given for a particular EDX system. The calculated change in the Cu K:Cu L ratio originates totally from absorption of the Cu L in the C. It can be seen from the figure that the ratio increases very significantly if a few hundred nanometres of C are deposited on the window. While the Cu K detection efficiency is constant, the Cu L detection efficiency falls away. This reflects the manner in which the softer (lower energy) signal is absorbed.
By actually measuring the Cu K and Cu L peaks using the MAC test specimen, data similar to that shown in the table can be obtained to monitor the detector performance.

Available to order as:
TEM-CAL— Cu foil mounted on a 3.05mm Ø Al TEM Grid

FOIL1 standards

Thin foil standards for STEM are available from the following materials:

These are high purity metal foils, each measuring 3mm diameter x 0.1mm thick which fit into TEM grid holders for use in the STEM mode.

FOIL25 standards

Sets of 25 standards for STEM are made of the same materials mentioned above available for FOIL1 standards.

FILM1 Thin Films Standards - Single

These standards are supplied as fine powders dispersed onto holey carbon films and are selected from a range of certified materials and synthetic compounds. They are supplied on 3.05mm grids.

Normally the holey carbon films are supported by 400 mesh copper grids although alternative grid materials can be specified.

Available materials:

FILM25 Thin Films Standards Set of 25 - Universal

These standards are supplied as fine powders dispersed onto holey carbon films and are selected from a range of certified materials and synthetic compounds. They are supplied on 3.05mm grids.

Normally the holey carbon films are supported by 400 mesh copper grids although alternative grid materials can be specified.

Available materials:

FILM14 Thin Films Standards Set of 14 - Rare Earth

These standards are supplied as fine powders dispersed onto holey carbon films and are selected from a range of certified materials and synthetic compounds. They are supplied on 3.05mm grids.

Normally the holey carbon films are supported by 400 mesh copper grids although alternative grid materials can be specified.

Available materials: