Development and application of positron microprobe

Maekawa, Masaki; Kawasuso, Atsuo; Hirade, Tetsuya ; Miwa, Yukio

We present the development and application of a positron microprobe. Positrons from a small positron source developed by us were moderated by a solid neon moderator, and were focused onto the specimen using the optics of conventional scanning electron microscope (SEM). At present stage, the beam diameter was determined by scanning the beam across a knife-edge, and was found to be about 3.9 micrometer. Two dimensional scanning measurement of a cracked sample (stress-corrosion cracking) was performed. In the region distant from the tip of a crack, increase of S-parameter was found, which are possibly associated with the vacancy defects.