Nuclear research: Using SIMS to study plasma facing materials (PFMs) in fusion reactors.

Monday, November 18, 2019

Co-authored by scientists from Wuhan & Hunan Universities in China, from Los Alamos National Laboratory with contribution from CAMECA SIMS experts Paula Peres and SeoYoun Choi, a new publication provides insight to help design irradiation-resistant PFMs used in fusion reactors.

Helium trapping and bubble formation in PFMs during operation of fusion reactors may lead to serious degradation of the PFMs’ properties. To ensure longevity of such materials, it is therefore important to understand He diffusion, migration and retention mechanisms.

He depth profiles were obtained by SIMS in nanochannel W film samples irradiated with 190 keV He+ ions at different fluences and temperatures. Measurements were performed on the CAMECA IMS 7f-Auto using Cs+ primary ions at 5 keV impact energy and collecting CsHe+ molecular ions, which is known to be an efficient method to overcome the high first ionization potential of He. The He detection limit, obtained from the measurement of a non-irradiated pristine nanochannel W film, was ~6 x 1017 atom/cm3 (about 10 ppm).

These SIMS results show that the existence of nanochannel structures do effectively facilitate the He release from the film even if the nanochannel W film is irradiated to such a low fluence, and that the higher the irradiation fluence, the more He atoms are released. On the other hand, the He releasing rate appears to be constant between RT and 300 °C but is significantly higher at a temperature of 600 °C.

Read the full article by Wenjing Qin et al.  in  Journal of Nuclear Materials, vol 527, 15 December 2019:
Influence of nanochannel structure on helium-vacancy cluster evolution and helium retention.

You may also be interested in:

Application notes
SIMS for Materials Analysis in Nuclear Science
Analysis of Fission Product Behavior with SIMS

Free on-demand webinar
Dynamic SIMS for Characterization of Nuclear Materials