TY - JOUR
T1 - Single atom sputtering events Direct observation of near-surface depleted zones in ion-irradiated tungsten
AU - Current, Michael I.
AU - Wei, Ching Yeu
AU - Seidman, David N.
N1 - Funding Information:
t This research was supported by the U.S. Department of Energy under Contract
Funding Information:
No. DE-AS02-76ER0315. Additional support was received from the National Science Foundation through the ,use of the technical facilities of the Materials Science Center at Cornell University. $ Present address : General Electric Corporate Research and Development Laboratory, Schenectady, New York 12305, U.S.A.
PY - 1981/1
Y1 - 1981/1
N2 - The three-dimensional spatial arrangement of vacancies contained in depleted zones (DZs) of ion-irradiated tungsten specimens, has been determined with atomic resolution by the field-ion microscope (FIM) technique. These DZs were detected in the near-surface region of specimens which had been irradiated in situ at ⩽ 15 K with 20 keV W+, 30 keV W+, Kr+, Cu+ or Ar+ ions. The values of the ion dose employed were small (⩽ 1013 ions cm−2); therefore, each DZ analysed was the result of the impact of a single projectile ion. At the irradiation temperature (⩽ 15 K) both the self-interstitial atoms and vacancies were immobile, so that the primary state of radiation damage was preserved. The following properties of each DZ were determined: (1) the total number of vacancies; (2) the number of vacancies in the near-surface region; (3) the spatial extent-that is, the dimensions required to determine a volume; (5) the average vacancy concentration associated with the near-surface region; (6) the first-nearest-neighbour cluster distribution for the vacancies in the near-surface region; (7) the radial distribution function of all the vacancies; (8) the distribution of vacancies as a function of depth normal to the irradiated surface; and (9) the sputtering yield, Most of the above properties of the near-surface DZs had similar values to those of the DZs detected in the bulk of the FIM specimens. The total number of vacancies detected in the near-surface region was approximately consistent with theoretical estimates of the average sputtering yield. The sputtering yield of individual DZs exibited significant fluctuations from the measured average sputtering yield.
AB - The three-dimensional spatial arrangement of vacancies contained in depleted zones (DZs) of ion-irradiated tungsten specimens, has been determined with atomic resolution by the field-ion microscope (FIM) technique. These DZs were detected in the near-surface region of specimens which had been irradiated in situ at ⩽ 15 K with 20 keV W+, 30 keV W+, Kr+, Cu+ or Ar+ ions. The values of the ion dose employed were small (⩽ 1013 ions cm−2); therefore, each DZ analysed was the result of the impact of a single projectile ion. At the irradiation temperature (⩽ 15 K) both the self-interstitial atoms and vacancies were immobile, so that the primary state of radiation damage was preserved. The following properties of each DZ were determined: (1) the total number of vacancies; (2) the number of vacancies in the near-surface region; (3) the spatial extent-that is, the dimensions required to determine a volume; (5) the average vacancy concentration associated with the near-surface region; (6) the first-nearest-neighbour cluster distribution for the vacancies in the near-surface region; (7) the radial distribution function of all the vacancies; (8) the distribution of vacancies as a function of depth normal to the irradiated surface; and (9) the sputtering yield, Most of the above properties of the near-surface DZs had similar values to those of the DZs detected in the bulk of the FIM specimens. The total number of vacancies detected in the near-surface region was approximately consistent with theoretical estimates of the average sputtering yield. The sputtering yield of individual DZs exibited significant fluctuations from the measured average sputtering yield.
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U2 - 10.1080/01418618108239396
DO - 10.1080/01418618108239396
M3 - Article
AN - SCOPUS:0019441563
SN - 0141-8610
VL - 43
SP - 103
EP - 138
JO - Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties
JF - Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties
IS - 1
ER -