  The high energy density of electronic excitations due to the impact of swift
heavy ions can induce structural modifications in materials. We present a X-ray
diffractometer called ALIX, which has been set up at the low-energy IRRSUD
beamline of the GANIL facility, to allow the study of structural modification
kinetics as a function of the ion fluence. The X-ray setup has been modified
and optimized to enable irradiation by swift heavy ions simultaneously to X-ray
pattern recording. We present the capability of ALIX to perform simultaneous
irradiation - diffraction by using energy discrimination between X-rays from
diffraction and from ion-target interaction. To illustrate its potential,
results of sequential or simultaneous irradiation - diffraction are presented
in this article to show radiation effects on the structural properties of
ceramics. Phase transition kinetics have been studied during xenon ion
irradiation of polycrystalline MgO and SrTiO3. We have observed that MgO oxide
is radiation-resistant to high electronic excitations, contrary to the high
sensitivity of SrTiO3, which exhibits transition from the crystalline to the
amorphous state during irradiation. By interpreting the amorphization kinetics
of SrTiO3, defect overlapping models are discussed as well as latent track
characteristics. Together with a transmission electron microscopy study, we
conclude that a single impact model describes the phase transition mechanism.
