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Updated: Jun 15, 2026
14:11
Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis
Published on: March 29, 2016
Interesting experimental results in Japan Proton Accelerator Research Complex H- ion-source development (invited)
1J-PARC Center, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan. akira.ueno@j-parc.jp
The Review of Scientific Instruments
|March 3, 2010
Summary
Researchers achieved high-intensity negative hydrogen (H-) ion beams using cesium-free ion sources. Optimizing plasma electrode design and lanthanum hexaboride filaments significantly boosted H- ion current for accelerators.
Area of Science:
- Particle Accelerators
- Plasma Physics
- Materials Science
Background:
- Negative hydrogen (H-) ion sources are crucial for high-energy particle accelerators.
- Cesium (Cs)-based sources have limitations, prompting research into Cs-free alternatives.
- Surface production mechanisms are key to efficient H- ion generation.
Purpose of the Study:
- To review experimental results from Japan Proton Accelerator Research Complex (J-PARC) H- ion-source developments.
- To demonstrate high-intensity H- ion production in cesium-free ion sources.
- To investigate the impact of plasma electrode (PE) optimization and filament materials on H- ion current.
Main Methods:
- Development and testing of Cs-free H- ion sources at J-PARC.
- Optimization of plasma electrode shape, temperature, and filament material (lanthanum hexaboride, LaB(6)).
- Utilized a high-power constant-current pulsed-arc power supply.
- Surface elemental analysis of the plasma electrode after operation.
Main Results:
- Achieved world-class H- ion current of 38 mA in Cs-free sources using optimized PE and LaB(6) filaments.
- Further increased H- ion current to over 40 mA by optimizing LaB(6) filament shape.
- Surface analysis revealed PE coated with boron (95.5%), lanthanum (2.5%), and oxygen (1.9%) when using LaB(6).
- Tungsten (W) filaments resulted in a ~20% decrease in H- ion current compared to LaB(6).
- Cesium seeding did not enhance H- current with LaB(6) filaments but increased it to >70 mA with W filaments.
Conclusions:
- Surface reactions are the primary mechanism for H- ion production in Cs-free J-PARC ion sources.
- Optimized plasma electrode design, high temperature, and LaB(6) filaments are critical for high-intensity Cs-free H- ion generation.
- LaB(6) filaments offer superior performance in Cs-free operation, while Cs seeding is more effective with W filaments.
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