• journal_title：American Mineralogist
• Contributor：Gregory R. Lumpkin ; Mark G. Blackford ; Katherine L. Smith ; Karl R. Whittle ; Nestor J. Zaluzec ; Edward A. Ryan ; Pete Baldo
• Publisher：Mineralogical Society of America
• Date：2010-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2010.3329
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：95
• issue：1
• firstpage：192
• section：Letters

Thin crystals of rutile, brookite, anatase, and cassiterite were irradiated in situ in the transmission electron microscope using 1.0 MeV Kr ions at 50–300 K. Synthetic rutile and natural cassiterite, with 0.1–0.2 wt% impurities, remain crystalline up to a fluence of 5 × 10¹⁵ ions cm⁻² without evidence for amorphization at 50 K. Natural brookite and anatase, with 0.3–0.5 wt% impurities, become amorphous at fluences of 8.1 × 10¹⁴ and 2.3 × 10¹⁴ ions cm⁻², respectively. We have also studied two natural rutile samples containing ~1.7 and 1.2 wt% impurities. These samples became amorphous at 9.2 × 10¹⁴ and 8.6 × 10¹⁴ ions cm⁻² at 50 K, respectively. Further analyses of the fluence-temperature data for natural brookite, rutile, and anatase give critical amorphization temperatures of 168 ± 11, 209 ± 8, and 242 ± 6 K, respectively. Results are briefly discussed with respect to several criteria for radiation resistance, including aspects of the structure, bonding, and energetics of defect formation and migration.