Radiation-induced amorphization of Langasite La3Ga5SiO14

Single crystals of Langasite La3Ga5SiO14 (LGS) were irradiated by 1 MeV Kr2+ ions at temperature range from 298 to 898  K in order to simulate the damage effect of neutron radiation on Langasite, a candidate sensor material proposed as high temperature and pressure sensors in nuclear reactors. The microstructure evolution of LGS as functions of irradiation dose and temperature was followed by in-situ TEM observation through electron diffraction pattern. LGS is found to be sensitive to ion beam irradiation-induced amorphization from displacive heavy ions with a low critical dose of ∼0.5 ± 0.2 dpa (neutron fluence of (1.6 ± 0.6 ) × 1019 neutrons/cm2) at room temperature. The critical amorphization temperature, Tc, is determined to be 910 ± 10  K. Under simultaneous ionizing electron (300  keV, 45  nA) and displacive heavy ion irradiations (1-MeV Kr2+ and flux of 6.25 × 1011 ions/cm2·s), LGS displayed greater stability of crystal structure against amorphization, possibly due to the electron radiation-induced recovery of displacive damage by heavy ions.