Tornado m4 micro xrf system

Fossils specimens were photographed using a digital camera (D3X-Nikon with Nikon Micro-Nikkor 60 mm lens) and measured (lengths, distances, angles) from high-resolution digital images by using Image J, a public domain processing program. Polished and lithological thin sections were made using standard methods and observed under binocular stereo-microscope (Leica MZ125 and Leica DM750P). Elemental maps were acquired using a Tornado M4 micro-XRF system (Bruker, Germany) equipped with a silicon drift detector and a Rh source operating at 50 kV and 600 µA. A spot size of 40 µm was employed with dwell times of 7 ms/pixel, and mapping was performed under vacuum. Image processing included spectral deconvolution and 3-pixel averaging. Tomographic images of ROMIP 57013 were obtained via the same methods and with the same machine as in Kouraiss et al.^{69 (link)}.

Samples for analysis were prepared by transferring mineralised cell monolayers onto an aluminium foil covered glass slide and leaving to dry overnight at room temperature. Maps of calcium and phosphorous across dried cell culture media spot samples were acquired using a Tornado M4 micro-XRF system (Bruker Nano, Germany) fitted with a Rhodium micro focus X-Ray tube and a polycapillary lens, with the X-ray tube set to 50 kV voltage and 300 μA current. The chamber pressure was lowered to 20 mbar in order to maximise sensitivity to the phosphorus signal. The system was programmed to acquire a map of the whole slide containing all of the media spot samples by rastering the microfocus beam over the slide with a step size of 30 μm and a time per pixel of 30 ms. An XRF spectrum was collected at each pixel and elemental maps generated progressively in real time by gating around the phosphorous K_α1 (2.0137 keV) and calcium K_α1 (3.692 keV) X-Ray fluorescence peaks in the spectra, creating an image where pixel intensity represented X-Ray detector pulses per eV at each measurement point on the sample. Maximum pixel intensity for each element was normalised to the peak pulses/eV value for that element across the whole sample.