Siyasanga Mpelane Vuyokazi Namntu Supervisor: V.A Skuratov Measurement of depth resolved photoluminescence spectra in swift Xe ions bombarded LiF crystals. Siyasanga Mpelane Vuyokazi Namntu Supervisor: V.A Skuratov

Outline Introduction Experimental set-up LiF depth profile measurements Results and discussions conclusion

introduction The overall intention of this practical work was to gain experience in optical spectroscopy applications,with the central objective being to study radiation damages in LiF crystals. Radiation damages in LiF will be studied by finding depth profiles of defects and correlated mechanical stresses in LiF crystals irradiated with Xe ions by using photoluminescence techniques. LiF crystals are favourable for radiation damage studies because of their large bang-gap energy of 14eV and their high ionic binding energy .

Experimental setup

Optical scheme Spectrometer 8 1 – Specimen 2 – Piezo stage 3 – Base 4– Lens 5 – Irradiated area 6 – Semitransparent mirror 7 – Filter 8 – Mirror aperture Digital camera 7 6 Laser 4 5 1 2 3

Color centers in LiF To monitor the lattice disoder in LiF, the luminescence of F-type centers was used. The F center consists of one anion vacancy and one electron, whereas the F2 center consists of two anion vacancies and two electrons. These color centers are defects which were produced by irradiation with Xe ions.

Results of the test measurements Irradiated area Irradiated area 50 100 Photos of LiF monocrystal, irradiated by Xe ions with the energy 1.2MeV/nucleon PL spectra measured at 3 and 16 μm

Results Calculations for elastic and non elastic energy losses Depth-resolved PL spectra measured on LiF specimens, irradiated with Xe ions with the energy of 1.2 MeV/nucleon The observed evolution f F3+ and F2+ center luminescence in LiF is ascribed to high concentration of defects in the ion track. In the are closer to the edge the F3+ centers are dominating and at the end of the ion range are dominating.

conclusion The experience in optical spectroscopy applications was gained. The depth profiles irradiated damage of LiF was successfully studied The F3+ and F2 centers were observed