Superconducting ECR ion source: From 24-28 GHz SECRAL to 45 GHz fourth generation ECR

Area of Science:

• Nuclear Physics
• Accelerator Science
• Plasma Physics

Background:

• Superconducting electron cyclotron resonance (ECR) ion sources are crucial for producing intense beams of highly charged ions.
• Increasing magnetic fields and microwave frequencies are the primary drivers for enhancing beam intensity and charge state performance.

Purpose of the Study:

• To present performance studies of the SECRAL (Superconducting ECR source) ion source operating at 24-28 GHz.
• To detail the technical design of the 45 GHz FECR (Fourth-generation ECR source), a next-generation superconducting ECR ion source.
• To demonstrate a technical pathway for advancing highly charged ion beam production.

Main Methods:

• Operation and analysis of SECRAL at 24 GHz and 28 GHz microwave frequencies.
• Commissioning of SECRAL-II with a 28 GHz gyrotron and multi-frequency heating.
• Technical design and development of the 45 GHz FECR ion source utilizing Nb3Sn superconducting magnets.

Main Results:

• SECRAL achieved record beam intensities for various ions (e.g., 1.4 emA 40Ar12+, 1.1 emA 129Xe26+).
• SECRAL-II demonstrated new record intensities for highly charged ions (e.g., 620 eμA 40Ar16+, 53 eμA 129Xe38+).
• Results confirm that higher microwave power and frequency are essential for more intense highly charged heavy ion beams.

Conclusions:

• The performance of SECRAL and SECRAL-II validates the scaling laws predicting the need for higher frequencies and power.
• The 45 GHz FECR represents a significant advancement, being the first Nb3Sn-based ECR ion source, pushing the frontier of highly charged ion beam generation.
• This work outlines a clear progression in ECR ion source technology from 24-28 GHz to 45 GHz for enhanced heavy ion beam production.