X-Ray Fluorescence Analysis
Comparison between EDXRF and WDXRF
The principal difference between ED and WDXRF techniques lies in the achievable energy (spectral) resolution. WDXRF systems can routinely provide working resolutions between 5 eV and 20 eV, depending on their set up, whereas EDXRF systems typically provide resolutions ranging from 150 eV to 300 eV or more, depending on the type of detector used.
The higher resolution of WDXRF provides advantages in reduced spectral overlaps, so that complex samples can be more accurately characterized. In addition, with high resolution backgrounds are reduced, providing improved detection limits and sensitivity.
However, the additional optical components of a WDXRF system (eg, diffracting crystal and collimators) means that it suffers from greatly reduced efficiency. Typically this is compensated for by high powered X-Ray sources, which can have a significant impact on cost and ease of use. The additional optical components of WDXRF also effect the cost, and make for a relatively expensive instrument.
The final difference lies in spectral acquisition. With an EDXRF system such as one of the XGT systems an entire spectrum is acquired virtually simultaneously, so that elements from across most of the periodic table can be detected within a few seconds. With WDXRF spectrum acquisition is either made in a point by point fashion (which is extremely time consuming), or else has a very limited number of simultaneous detectors (which is an expensive option).