Non-destructive SEM-based EDS analyses of (naturally) non-conductive life science samples can be very challenging due to charging effects and electron beam damage. In addition, topograph and resulting shadowing effects impact the quality of results. The Bruker XFlash® FlatQUAD is specifically designed to overcome such limitations, as demonstrated in the present example of a sea urchin (Paracentrotus Lividus) from the Aegean Sea near Athens, Greece.
Fig. 1-3 show SEM-based EDS maps of various details of a sea urchin. In Fig. 1, spine tubercles are visible on the right in turquoise, while the green and turquoise spade-like structures on the left are minuscule spines. In the center of the micrograph individual sand grains are discernable in red. This map was acquired without any sample preparation (i.e. no carbon coating nor polishing) under high vacuum conditions at 6 kV acceleration voltage and low beam current using an annular SDD (XFlash® FlatQUAD).
This unique annular EDS detector is placed above the sample, like a BSE detector would be. The XFlash® FlatQUAD has an extremely high sensitivity for low X-ray yield, minimizing any shadowing effects and hence is a perfect tool for mapping rough surface, beam sensitive samples like for some life science applications.