New X-ray microprobe system for trace heavy element analysis using ultraprecise X-ray mirror optics of long working distance

A new X-ray microprobe system for trace heavy element analysis using ultraprecise X-ray mirror optics of 300 mm long working distance has been developed at beamline 37XU of SPring-8. A focusing test has been performed in the X-ray energy range 20–37.7 keV. A focused beam size of 1.3 μm (V)×1.5 μm (H) has been achieved at an X-ray energy of 30 keV, and a total photon flux of the focused beam was about 2.7×1010 photons/s. Micro-X-ray fluorescence (μ-XRF) analysis of eggplant roots has been carried out using the developed microprobe. It is clearly observed in the XRF images that cadmium is highly accumulated in the endodermis, exodermis and epidermis of roots. This study demonstrates the potential of scanning microscopy for heavy elements analysis in the high-energy X-ray region.