Production of cation vacancies in alkali halides by ionizing radiation

1975 ◽  
Vol 18 (3) ◽  
pp. 410-411
Author(s):  
A. A. Vorob'ev ◽  
Yu. M. Annenkov ◽  
V. F. Pichugin ◽  
T. S. Frangul'yan ◽  
A. P. Nesterenko
Keyword(s):  
Ionizing Radiation ◽  
Alkali Halides ◽  
Cation Vacancies

Formation of Interstitials in Alkali Halides by Ionizing Radiation

1959 ◽  
Vol 116 (2) ◽  
pp. 314-315 ◽  
Author(s):  
R. E. Howard ◽  
R. Smoluchowski
Keyword(s):  
Ionizing Radiation ◽  
Alkali Halides

A study of interstitial clusters in irradiated alkali halides using direct electron microscopy

1973 ◽  
Vol 332 (1589) ◽  
pp. 167-185 ◽  
Keyword(s):  
Ionizing Radiation ◽  
Room Temperature ◽  
Alkali Halides ◽  
Lattice Parameter ◽  
Dislocation Loops ◽  
Direct Production ◽  
Predominant Type ◽  
Temperature Irradiation ◽  
Planar Dislocation ◽  
Alkali Halide Crystals

A direct electron microscope study has been made of defect clusters produced in alkali halides by ionizing radiation. A technique has been developed for preparing foils of alkali halide crystals less than a few hundred nanometres thick for observation in the microscope, and a liquid helium cooled stage allows the study of irradiated crystals down to 5 K. At this temperature it has been possible to analyse in detail clusters produced at other temperatures, without confusion from observable damage produced by the investigating election beam. Irradiations have been performed both in the 100 keV microscope beam and externally using γ rays or 400 keV electrons. In this way irradiation products in KI have been extensively studied. The predominant type of defect cluster produced in several alkali halides by room temperature irradiation has contrast typical of planar dislocation loops. Tilt/contrast experiments performed in KI show conclusively that the loops are interstitial in character, and the numbers of point defects involved and the temperature dependence of their growth indicate that mobile interstitial halogen atoms are required for their formation. The loops have Burgers vectors b ═ 1/2 a (110) where a is the lattice parameter. The habit plane of a loop with b ═ 1/2 a [101] lies between (001) and (101). An unfaulted interstitial dislocation loop with Burgers vector 1/2 a <110> formed by condensation of equal numbers of anion and cation interstitials can account for the observed features of the clusters. However, since there is little evidence for the direct production of cation Frenkel pairs by ionizing radiation in alkali halides, alternative models are presented in which the cluster forms primarily as a result of the initial aggregation of halogen interstitials alone. These models are shown to be consistent with specific features of the radiation damage behaviour of alkali halides.

Radiation-induced surface decomposition

1983 ◽  
Vol 41 ◽  
pp. 368-369
Author(s):  
M. L. Knotek
Keyword(s):  
Ionizing Radiation ◽  
Atomic Structure ◽  
Chemical Bonding ◽  
Neutral Species ◽  
Radiation Induced ◽  
Physical And Chemical ◽  
Surface Decomposition ◽  
The Relationship ◽  
Electron And Photon ◽  
Surface Bond

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.

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