Enhancement of SPES source performances.

Area of Science:

• Nuclear Physics
• Accelerator Physics
• Plasma Physics

Background:

• The SPES (Separatore di Particelle Elementari) ion source was installed at Laboratori Nazionali del Sud (LNS) in July 2006.
• Initial commissioning in September 2006 showed excellent extracted current density but poor source reliability.

Purpose of the Study:

• To investigate and resolve the glow-discharge phenomena affecting SPES ion source reliability.
• To optimize the magnetic field configuration for stable ion beam extraction.

Main Methods:

• Investigated glow-discharge phenomena caused by axial magnetic field protrusion into the high-voltage column.
• Replaced the stainless steel plasma electrode support with a ferromagnetic material.
• Recalculated ion source solenoid positions and magnetic fields.
• Performed magnetic simulations and experimental validation of high-voltage column shielding.

Main Results:

• Identified magnetic field protrusion as the cause of poor source reliability.
• The ferromagnetic support effectively shielded the high-voltage column, eliminating glow-discharge.
• Optimized solenoid configuration recovered the correct resonance pattern for stable operation.
• Achieved reliable operation of the SPES ion source post-modification.

Conclusions:

• The modification of the plasma electrode support with ferromagnetic material successfully resolved reliability issues in the SPES ion source.
• Magnetic field shielding and optimized solenoid configuration are crucial for stable operation of high-current ion sources in accelerator environments.
• The study provides valuable insights into mitigating magnetic field interference in ion source design.