CRISP: A compact RF ion source prototype for emittance scanner testing

Area of Science:

• Plasma Physics
• Accelerator Technology
• Fusion Energy

Background:

• Development of a movable Allison type emittance scanner is crucial for characterizing beamlet phase-space distributions.
• This scanner is intended for the ITER heating neutral beam injector's prototype RF negative ion source.

Purpose of the Study:

• To test the electronics and verify the capability of the Allison scanner to resolve nearby beamlets.
• To characterize a compact RF ion source prototype and assess its suitability for scanner commissioning.

Main Methods:

• A compact RF ion source prototype was constructed using a Pyrex tube and a 100 W RF generator.
• Plasma generation with densities of 10^15–10^16 m^-3 and electron temperatures up to 15 eV was achieved.
• Ions were extracted and accelerated using a three-grid accel-decel system and measured with a Faraday cup.

Main Results:

• The RF ion source prototype successfully accelerated 1 mA of helium ions to 2 kV.
• Characterization of the ion source and its initial operation were presented.
• The ion source demonstrated suitability for the commissioning of the Allison scanner.

Conclusions:

• The compact RF ion source prototype is a viable tool for testing and commissioning the Allison type emittance scanner.
• This development contributes to the advancement of diagnostic tools for fusion energy research, specifically for ITER.