Operation and development status of the J-PARC ion source

Area of Science:

• * Accelerators and particle physics
• * Ion source technology

Background:

• * The Japan Proton Accelerator Research Complex (J-PARC) utilizes a cesium-free H(-) ion source with a LaB6 filament.
• * Routine operation achieved approximately 19 mA H(-) ion current.
• * Post-earthquake restoration has ensured stable operation.

Purpose of the Study:

• * To increase beam power for linac operations by enhancing H(-) ion current.
• * To evaluate filament lifetime under increased current conditions.
• * To prepare for future upgrades, including a new RF-driven H(-) ion source.

Main Methods:

• * Operated the H(-) ion source at increased currents (22 mA and 30 mA).
• * Monitored filament current reduction to predict and manage filament failure.
• * Prepared for filament exchange to minimize downtime.

Main Results:

• * Successfully increased H(-) ion current to 22 mA for linac operations.
• * Achieved a 30 mA H(-) ion current for 8 days during synchrotron studies.
• * Filament failure was predicted by steep current reduction, with downtime minimized through preparation.

Conclusions:

• * The LaB6 filament H(-) ion source can be operated at higher currents, supporting J-PARC's beam power upgrade plans.
• * Filament lifetime management is crucial for sustained high-current operation.
• * Development and testing of a new RF-driven H(-) ion source are underway for future J-PARC requirements.