Recent development of RIKEN 28 GHz superconducting electron cyclotron resonance ion source

Area of Science:

• Nuclear Physics
• Plasma Physics
• Accelerator Technology

Background:

• The RIKEN superconducting electron cyclotron resonance ion source (SC-ECRIS) is crucial for producing ion beams.
• Improving the performance of SC-ECRIS for heavy elements like uranium is essential for various applications.
• Previous methods for uranium vapor production had limitations in operational duration or beam intensity.

Purpose of the Study:

• To enhance the performance of the RIKEN SC-ECRIS for producing highly charged uranium ions.
• To investigate the effectiveness of the sputtering method for long-term uranium ion production.
• To optimize beam intensity and stability by exploring various operational parameters.

Main Methods:

• Utilized the sputtering method for uranium (U) vapor production, enabling extended operation.
• Replaced the standard stainless steel plasma chamber with an aluminum chamber.
• Investigated the impact of radio frequency (RF) power and sputtering voltage on beam intensity and stability.

Main Results:

• Achieved beam intensities of approximately 180 eμA for U(35+) and 230 eμA for U(33+) at ~4 kW RF power (28 GHz).
• Demonstrated successful long-term operation using the sputtering method with a large material capacity.
• Initiated development of a high-temperature oven to further increase U(35+) beam intensity.

Conclusions:

• The sputtering method combined with an aluminum chamber significantly improved the performance of the RIKEN SC-ECRIS for producing highly charged uranium ions.
• Optimizing RF power and sputtering voltage is key to maximizing beam intensity and ensuring beam stability.
• Ongoing development of a high-temperature oven shows promise for even higher beam intensities.