2.7.2. Facility Conditions
Arsenic Content, Speciation, and Distribution in Wild Cordyceps sinensis
Evid Based Complement Alternat Med, Feb 19, 2021; DOI: 10.1155/2021/6651498

The distribution of As in C. sinensis samples was analyzed with μ-XRF at the beamline BL15U at the Shanghai Synchrotron Radiation Facility (SSRF, Shanghai, China). The continuous synchrotron X-rags were monochromatized by a Si(111) double-crystal monochromator. A monochromatic X-ray beam with photon energy of 13 keV was used to excite the samples. The cross section of the beam irradiation on the samples was adjusted to about 200 × 200 mm2 with an about 1011 phs/s photon flux. The sample was placed at a 45° angle to the incident X-ray beam, and X-ray fluorescence was detected with a 50 mm2 silicon drift detector (Vortex, USA) oriented at a 90° angle to the incident beam. A light microscope was coupled to a computer for sample viewing. The sample platform was moved by a motorized x-y mapping stage. The As distributions in the sections of different parts of the caterpillar were continuously scanned at a step of 125 μm for both x and y directions. Each spot was irradiated for 5 s.