Naslov
Lowering threshold for ion track formation: implications for nuclear waste immobilization

Autori
Tomić, Kristina ; Heller, Rene ; Akhmadaliev, Shavkat ; Lebius, Henning ; Ghica, Corneliu ; Bröckers, Lara ; Schleberger, Marika ; Scholz, Ferdinand ; Rettig, Oliver ; Siketić, Zdravko ; Šantić, Branko ; Jakšić, Milko ; Fazinić, Stjepko ; Karlušić, Marko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
EMRS 2018 spring meeting Program guide / - , 2018, 150-150

Skup
Spring Meeting & Exibit (MRS2018)

Mjesto i datum
Phoenix (AZ), Sjedinjene Američke Države, 02.04.2018. - 06.04.2018

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
ion tracks ; energy materials ; swift heavy ions ; insulators ; defects ; radiation effects

Sažetak
Stability of materials in radiation harsh environment is an important issue because damage build-up within a material in such an environment can exhibit complex behavior. Of special interest is the response of materials to fission-fragments that can produce extended damage known as fission tracks. To address this, the response of a wide range of crystalline ceramics to swiftheavy ion (i.e. fission fragment-like) irradiation has been systematically investigated for nuclear waste applications [1-3]. Dense electronic excitation in the wake of the swift heavy ioncan lead to nanoscale material damage along its trajectory called ion(i.e. fission) track. The thermal spike scenario describes this process as a transfer of the deposited swift heavy ion energy from the electronic subsystem into the phonon subsystem via electron-phonon coupling. If the density of the deposited energy is sufficient to induce melting, then an ion track can be formed during rapid quenching of the melt.Otherwise, the deposited energy simply dissipates away without producing damage. This is the origin of the ion track formation thresholdthat is nowadays known for many materials. Clearly, high values of this threshold are desirable for materials used in nuclear energy applications, and any lowering of these threshold values can have significant, detrimental effects. In this contribution we present results of our RBS/c, TEM and AFM investigations about ion track formation thresholds in swift heavy ion irradiation resistant materials MgO, Al2O3, MgAl2O4 and GaN. In case of oxides, we compare thresholds for ion track formation in the bulk [3], [4] and on the surface [5]. Based on the atomic force microscopy measurements, we present evidence that ion tracks can be easily formed on the oxide surface after grazing- incidence swift heavy ion irradiation. Similar to our previous studies on ion tracks on GaN, SrTiO3 and TiO2 surfaces [6-8], we show how the threshold for ion track formation can be significantly reduced by applying grazing incidence irradiation geometry. Another way how thisthreshold can be reduced is via introduction of defects, usually by means of low energy ion irradiation. Recently, synergistic effects of nuclear and electronic energy loss came into research focus, for example defects in SrTiO3can promote ion track formation [9], [10]. As a follow-up of our previous study on GaN[6], we investigated the role of defects in this material with respect to the ion track formation and report additive effects similar to the case of SrTiO3. [1] W. J. Weber et al., Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium, J. Mat. Res. 13 (1998) 1434. [2] W. J. Weber et al., Materials Science of High-Level Nuclear Waste Immobilization, MRS Bulletin 34 (2009) 46. [3] G. Szenes, Ion-induced amorphization in ceramic materials, J. Nucl. Mater. 36 (2005) 81. [4] S.J. Zinkle et al., On the conflicting roles of ionizing radiation in ceramics, Nucl. Instr. Meth. B 191 (2002) 758. [5] V.A. Skuratov et al., Surface modification of MgAl2O4 and oxides with heavy ions of fission fragments energy, Nucl. Instr. Meth. B 250 (2006) 245. [6] M. Karlušić et al., Response of GaN to energetic ion irradiation - conditions for ion track formation, J. Phys. D: Appl. Phys. 48 (2015) 325304 [7] M. Karlušić et al., Swift heavy ion track formation in SrTiO3 and TiO2 under random, channeling and near-channeling conditions, J. Phys. D: Appl. Phys. 50 (2017) 205302. [8] M. Karlušić et al., Formation of swift heavy ion tracks on a rutile TiO2 (001) surface, J. Appl. Cryst. 49 (2016) 1704. [9] W.J. Weber et al., Synergy of elastic and inelastic energy loss on ion track formation in SrTiO3, Sci. Rep. 5 (2015) 7726. [10] H. Xue et al., Amorphization due to electronic energy deposition in defective strontium titanate, Acta Materialia 127 (2017) 400.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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