Soft X-ray Irradiation of Silicates: Implications on Dust Evolution in
  Protoplanetary Disks
  The processing of energetic photons on bare silicate grains was simulated
experimentally on silicate films submitted to soft X-rays of energies up to
1.25 keV. The silicate material was prepared by means of a microwave assisted
solgel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry
with residual impurities due to the synthesis method. The experiments were
performed using the spherical grating monochromator beamline at the National
Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray
irradiation induces structural changes that can be interpreted as an
amorphization of the processed silicate material. The present results may have
relevant implications in the evolution of silicate materials in X-ray
irradiated protoplanetary disks.
