Application of Positron Microprobe for Nuclear Materials
We have developed a positron microbeam using magnetic lenses based on the commercial scanning electron microscope. The minimum beam diameter was 1.9 μm on target. Two-dimensional image of S parameter was successfully obtained. Using this apparatus, S parameter distribution around the crack tip introduced by a stress corrosion cracking of a stainless steel was obtained. S parameter increases at the further region of the tip of the crack. This shows that vacancy type defects may be generated as crack precursor.
S. J. Wang, Z. Q. Chen, B. Wang and Y. C. Jean
M. Maekawa et al., "Application of Positron Microprobe for Nuclear Materials", Materials Science Forum, Vol. 607, pp. 266-268, 2009