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Updated: Jul 8, 2026
10:42
Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
Production of a positron microprobe using a transmission remoderator
Masanori Fujinami1, Satoshi Jinno, Masafumi Fukuzumi
1Department of Applied Chemistry, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan. fujinami@faculty.chiba-u.jp
Summary
Researchers developed a positron microprobe using a sodium-22 source. This technique enhances positron beam brightness for detailed 3D defect analysis in materials science.
Area of Science:
- Materials Science
- Nuclear Physics
- Surface Science
Background:
- Positron microprobes are valuable tools for materials characterization.
- Existing methods often require large accelerator facilities.
- Developing compact, efficient positron sources is crucial for broader accessibility.
Purpose of the Study:
- To investigate a production method for a positron microprobe using a radioisotope source.
- To achieve high brightness and spatial resolution for positron beams.
- To enable detailed analysis of vacancy-type defects in materials.
Main Methods:
- Utilized a beta+-decay radioisotope (22Na) as the positron source.
- Employed magnetic lenses and an extraction coil for beam focusing and transport (71% efficiency).
- Used a nickel thin film as a remoderator for brightness enhancement in transmission geometry.
Main Results:
- Successfully transformed a 4-mm positron beam into a microprobe of 60 microm or less.
- Achieved a total efficiency of 4.2% for the positron microprobe system.
- Demonstrated the technique's capability by correlating S parameter profiles with defect distribution.
Conclusions:
- The developed positron microprobe offers a viable alternative to accelerator-based sources.
- This method enables 3D vacancy-type defect analysis with high spatial resolution.
- The technique is suitable for creating positron sources for transmission positron microscopes.
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