Characterization of collision cascade damage in Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} by HRTEM
Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} thin crystals become amorphous under ion beam irradiation. The ion dose required for complete amorphization of the thin crystal (critical amorphization dose, D{sub c}) increased with the increasing irradiation temperature and decreased with ion mass at elevated temperatures. Samples irradiated with 1-1.5 MeV Ar{sup +}, Kr{sup +} and Xe{sup +} ions to doses much lower than Dc, in the temperature range from 20 to 498 K were used for a detailed HRTEM study to better understand the amorphization process. The residual collision cascade damage after irradiation appeared as manometer scale amorphous domains. The images of these domains are extremely sensitive to the sample thickness. Small domains of cascade size were only found at the very thin edge of the sample. In thicker regions, amorphous domains appear after higher doses as the result of cascade overlap in projection. At higher temperatures, the observed amorphous domains are smaller indicating thermal recovery at the amorphous/crystalline interface. The amorphous domains are also larger in size after irradiation with ions of higher mass at a fixed ion dose. These results are consistent with the Dc-temperature curves determined by in situ TEM with the HVEM-Tandem Facility at Argonne National Laboratory. The width of the amorphous rim along the edge of the specimen grew with increasing ion dose suggesting that amorphization also proceeds from the sample surface. Images of the collision cascade damage were compared to the cascade sizes calculated with the TRIM code. Some digitally acquired HRTEM images of the cascade damage were processed to reveal more detailed information.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10116226
- Report Number(s):
- PNL-SA-25554; CONF-941144-45; ON: DE95005719; TRN: 95:001746
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS),Boston, MA (United States),28 Nov - 9 Dec 1994; Other Information: PBD: Dec 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
CALCIUM OXIDES
PHYSICAL RADIATION EFFECTS
MICROSTRUCTURE
LANTHANUM OXIDES
SILICON OXIDES
CERAMICS
THERMAL RECOVERY
AMORPHOUS STATE
TRANSMISSION ELECTRON MICROSCOPY
APATITES
TEMPERATURE DEPENDENCE
ION-MOLECULE COLLISIONS
POINT DEFECTS
360206
400600
RADIATION EFFECTS
RADIATION CHEMISTRY