How rusty is Mars?
Beagle 2's Mossbauer spectrometer produced by the University
of Mainz will provide information about the nature of iron
in mineral samples by measurement of the Doppler shift in
the velocity (or energy) of gamma rays emitted by a stationary
target bombarded by a source of gamma rays from the decay
of 57Co to 57Fe. The electronic environment
of atoms in a sample dictates the absorption characteristics
and thus they give spectra dependant on their valence state
and bonding. The strength of the signals is quantifiable and
thus the Mossbauer spectrometer can give valuable information
about the mineralogical make-up of the rocks and soils. The
ability to measure valence gives important information about
oxidation state and will be used to determine the degree to
which iron is in the oxidised form.
X-ray analysis
The X-ray detector which is carried on Beagle 2 will provide
elemental compositions from the energy spectrum of X-rays
produced by bombarding samples with radiation from either
109Cd or 55Fe sources. This will be
provided by the University of Leicester. A primary goal is
measurement of the potassium content for age dating purposes
(see Rock Ages under Mass Spectrometer). Quantifying major
elements Mg, Al, Si, S, Ca, Ti, Cr, Mn and Fe will help in
identifying rock types and aid the interpretation of Mossbauer
spectra.
