The X-ray diffraction and fluorescence tests of a Martian analogue rock carried out by the University of Leicester are presented. A simulation chamber consists of CCD, X-ray source, source collimator and sample table is designed and developed in support of the in situ mineralogical and chemical analysis instrument of the planetary surface exploration.

A reflection XRD geometry is selected for the benefit of wider two-theta angle coverage and easier sample preparation. In order to maximize the operation reliability of the in situ remote instrument, all parts are designed as the fixed components. So the 2-Dimension CCD would be a good candidate chosen for the detector, and both position and energy related X-ray events could be stored simultaneously. An array of CCDs in-line  could extend the two-theta angle coverage, therefore in our chamber, we simulated this by using an XMM EPIC CCD22 manufactured by e2v Technologies mounted on a motorized rotating arm. The source we used is a conventional X-ray tube with copper anode and with anode coated by the manganese powder. Both Cu-Ka and Mn-Ka characteristic X-rays are tested in our chamber. ⁵⁵Fe radioactive source will be the next one to choose in the test.

The Theo’s flow rock is from the Pyroxenite layer, 60 meter below the surface of Ontario Canada. It’s believed that the composition of the rock is similar to the Martian Nakhlites. The sample was prepared by crushing the rock and pressing the powder into a pellet disk. The results show the X-ray spectrum and diffractogram. By analyzing these results, the possible elemental and mineral composition could be carried out. Also the sample has been tested by a commercial XRD/XRF instrument from Department of Geology in University of Leicester. The comparison of the laboratory results and commercial ones suggests that the planetary surface XRD/XRF instrument implementation is feasible. Figure 1. Comparison of laboratory and commercial XRD instrument diffractogram of Theo’s flow rock Martian analogue sample.

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1. A Monte Carlo ray-tracing model for planetary applications of x-ray powder diffraction and fluorescence