engleski

Ion track formation in radiation hard materials: examples of GaN, MgO, MgAl2O4 and Al2O3

High thresholds for ion track formation and rather small ion track sizes characterize response of radiation hard materials to swift heavy ion irradiation. In the present contribution, we report two different approaches to lower the threshold for ion track formation in selected materials. Previous studies showed that GaN is resistant to ion track formation up to ~20 keV/nm electronic stopping power [1, 2]. Here we report results of ion track experiments on GaN, where the material has been pre-irradiated by 2 MeV Au ions. In this way, defects have been introduced into GaN via nuclear stopping mechanism. This modified material shows a much greater susceptibility to ion track formation, which is observed already at 8 keV/nm electronic stopping power, as evidenced by RBS/c and AFM measurements. Next, we present results of grazing incidence swift heavy ion irradiation of MgO, Al2O3 and MgAl2O4. Previous studies demonstrated high thresholds for ion track formation on the surfaces of these materials, around 10-15 keV/nm [3]. Here we show long surface ion tracks can be found at stopping powers as low as 8 keV/nm if grazing incidence irradiation is applied. Additional experiments showed that these materials are also radiation hard with respect to highly charged ion irradiation.

swift heavy ion ; ion track

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