Imaging conditions and methods in the latest ultra-high resolution FEG-SEMs for investigating the morphology and structure of the smallest nano-materials and layers utilises very low kV, minimum beam current and short working distance. These conditions are incompatible with current conventional EDS detectors due to limits to sensitivity and geometry. A new design approach for EDS detectors, ‘X-Max Extreme’ specifically provides elemental characterisation under these imaging conditions. The detector front end has been re-designed to minimise sample to crystal distance and operating working distance. The electron trap volume has been significantly reduced to stop low kV backscatter electrons to minimise footprint. A windowless approach is used to maximise the sensitivity to low energy X-rays. Improvements in sensitivity of 10 times for sub 1000eV X-rays have been achieved over conventional large area SDD. This detector is used with accelerating voltages in the range 500eV to 3kV to maximise spatial resolution.