Proton Linac Development Division
Electron Cyclotron Resonance (ECR) Ion Source

Electron Cyclotron Resonance (ECR) ion source have been widely used for the production of singly and multiply charged ion beams. In ECR plasma, plasma is produced by matching the cyclotron frequency of an electron in a DC applied magnetic field with the microwave frequency. ECR proton source at 2.45 GHz microwave frequency have been designed and developed. 8 mA proton beam current extracted up to 25 keV beam energy. The major components are, plasma and vacuum system, microwave system, electromagnet and its power supply,and beam extraction electrode geometry. A base pressure in the plasma chamber and vacuum chamber is maintained ~10-6 mbar using Turbo-molecular pump (500 l/sec). 6.35mm diameter stainless steel (SS304L) tube has been used for hydrogen gas flow and maintain 10-3 to 10-4 mbar in the plasma chamber for plasma production. Magnetron (2.45 GHz, 2 kW) is used as a source of microwave power. The microwave system was developed using WR-284 rectangular waveguide. Three water cooled electromagnet solenoid coils were fabricated for confinement and generation of plasma. For ECR resonance at 2.45 GHz frequency, the required magnetic field is 875 gauss. To extract the proton beam from the source, three-electrode geometry (plasma electrode, extraction electrode and ground electrode) was used. The extracted proton beam was measured using Faraday cup. The design parameters of the RRCAT-ECRIS is shown in following table.

Design parameters of the RRCAT-ECRIS
Description Design Parameter
Beam Energy 50 keV
Beam Current 30 mA CW
Particles H+
Microwave Frequency 2.45 GHz
Magnetic Field (ECR resonance) 875 gauss
Emittance (rms-normalized) ≤ 0.2 π mm-mrad
Photograph of RRCAT-ECR Ion Source

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