MARSX : an autonomous Xray diffraction

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MARS-X an autonomous X-ray diffraction
fluorescence instrument for use on Mars
R. Delhez1, A.D. Holland2, I.B. Hutchinson2, N.H.
Nelms2, I.L. Ten Kate3, S.J. Van der Gaast4, A.A.
Wielders5, and F. Westall6 1 Laboratory of
Materials Science and Technology, Delft
University of Technology, Rotterdamseweg 137,
2628 AL Delft, The Netherlands 2 Space Research
Centre, Dept. Physics Astronomy, University of
Leicester, University Road, Leicester, LE1 7RH,
UK 3 Leiden Observatory, Leiden University, Niels
Bohrweg 2, 2333 CA Leiden, The Netherlands 4
Royal Netherlands Institute for Sea Research,
P.O. Box 59, 1790 AB Den Burg, The Netherlands 5
TNO-TPD Institute of Applied Physics,
Stieltjesweg 1, 2600 AD Delft, The Netherlands 6
Centre de Biophysique Moleculaire, Centre de
Biophysique Moleculaire, Rue Charles-Sadron 45071
Orleans cedex 2, France
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Goals

• Search for mineral deposits and structures that
  indicate formation by organisms
• Search for minerals that can host molecules of
  life on Mars
• Mineralogy of rocks, deposits and dust that helps
  interpretation of general geology of Mars

The mineralogy of the surface material of Mars
is the key to disclose its present and past life
and climates.
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The best tool is XRD/XRFWe propose Mars-X a
tandem XRD/XRF instrument

• Identification of a wide range minerals
• Semi-quantitative phase determination
• High resolution large spacings
• Preferred orientation of crystallites
• Lattice deformation lattice imperfection
• Crystallite sizes
• Average particle size
• Mars-X is better
• Mars-X is unique

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The Mars-X combines

• XRF
• information on chemical composition
• Transmission mode
• CCD-XRPD for quick and dirty analysis of
  powders
• Reflection mode
• accurate work on rocks and soils

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Diffraction grains

• Braggs law implies angle of incidence angle
  of reflection
• and therefore only few grains diffract
  simultaneously
• In different crystallites the same lattice
  planes have different orientations with
  respect to the specimen surface
• and therefore diffract at different
  specimen tilt angles y

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• Diffractometer
• Low power X-ray tube
• CCD detection system for transmission mode - and
  for XRF
• Parallelogram construction for reflection mode
• with solid state position sensitive
  detector and De Wolff slit
• Specimen preparation
• Sample acquisition and transportation robotic
  arm
• Specimen holders for transmission reflection
  mode
• Device for powder preparation
• Device for surface preparation for in-situ
  measurements
• Data
• Special data acquisition and evaluation software
• Selective storage and transmission of X-ray data
  / results
• Breadboard model (without robotic arm)
• Estimated total mass 5 kg with power
  consumption 5-20 Watt

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The Mars-X in conclusion

• Unique feature combination XRF dual XRD
• Instrument specimen preparation software
• Unique abilities
• Working prototype really portable instrument
• Ambitious design
• ESA requires co-operation with MAX

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Diffraction line broadening

• broadened line profiles reference line
  profile