Experimental and calculated depth distributions of damage and projected ranges of 20-keV 4He ions in nickel

Abstract

A recently improved sample-sectioning technique allowed us to obtain the entire depth distribution of damage (e.g., cavities) produced by 20-keV 4He+ ions injected into annealed, polycrystalline nickel held at 500 °C. We have also obtained the depth profile of the implanted helium concentration using the elastic recoil detection technique. These experimental depth profiles have been used to test several theoretical predictions for projected range and energy deposition profiles (e.g., based on transport theory or Monte Carlo calculations).

Depth distribution of 20-keV helium ion irradiation induced cavities in nickel

“…The results presented aoove, together with our previous data [12,17,19] for 20-and 500-keV implantations of nickel provide detailed information on the mechanisms involved in blistering.…”

“…2d and the measured volume swelling distribution in Fig. 2c has been discussed in greater detail elsewhere [19]. Fig.…”

“…2d. This discrepancy has been attributed [19] to inaccurate data on the electronic stopping power for this energy range, and to the neglect of the influence of volume swelling on the calculation of the range and energy deposition profiles.…”

“…This transverse sectioning technique, whose details are described elsewhere [21], permitted us to study the entire depth distribution of bubbles from a single section. Similar techniques have been used to study the depth distribution of damage [22] and voids [23][24][25] but with the exception of our recent paper [19], no quantitative data has been reported for 20-keV 4 He+ implanted nickel. Transmission electron micrographs of the cavities in the implanted region were analyzed to determine the average cavity diameter, number density and volume swelling as a function of depth from the implanted foil surface usins a Zeiss particle size analyzer.…”

“…Finally, these studies should help to clear up a reported discrepancy [18] between calculated projected ranges and the thickness of exfoliated blister skins for 20-keV *He+ irradiations of annealed nickel. We reported earlier [19] that for 20-keV *Ev + irradiations the skin thicknesses were about twi~.e the calculated MASTEH average projected ranges using Brice's computer codes [20] together with LSS electronic stopping and Thomas-Fermi nuclear stopping powers.…”