ECR-ion source SOPHIE

ECR = Electron Cyclotron Resonance

In an ECRIS, plasma is created and heated by microwaves with a frequency corresponding to the strength of a magnetic field applied from the outside. For electrons in an exterior magnetic field, the ECR-theorem holds and microwaves with a frequency of



(e being the elementary charge, m_e the electron’s mass and B_ecr the exterior magnetic field) excite the electrons at their cyclotron resonance frequency. This magnetic field is also used for plasma confinement (magnetic mirror). Inside the plasma, the heated electrons collide with the gas molecules and successively ionize them. Multiply charged ions are then extracted by means of an electrostatic extraction system.

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The figure on the right shows a schematic of SOPHIE, our 14.5 GHz ECRIS here at the Atomics and Plasma Physics group. The magnetic confinement field is generated by four permanent magnet rings and a Halbach-type hexapole magnet with 80 mm outer diameter. Two of the rings are axially and two are radially magnetized and thus provide the axial mirror field with a maximum of about 0.9 T.

The microwave power supply consists of a thin film oscillator, permitting a continuous operation between 12.75 and 14.5 GHz, and a traveling wave tube amplifier with 200 W amplification power.

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“Our” SOPHIE :)

E. Galutschek, R. Trassl, E. Salzborn, F. Aumayr and HP. Winter
Compact 14.5 GHz all-permanent magnet ECRIS for experiments with slow multicharged ions
Journal of Physics: Conference Series 58 (2007) 395 - 398
more detailed description in pdf-Format

M. Leitner, D. Wutte, J. Brandstötter, F. Aumayr and HP. Winter
Single-stage 5-GHz ECR-multicharged ion source with high magnetic mirror ratio and biased disk
Review Scientific Instruments 65 (1994) 1091 - 1093

D. Wutte, M. Leitner and HP. Winter
A 2.45-GHz electron cyclotron resonance multi-mA Li⁺ ion gun for fusion plasma diagnostics
Review Scientific Instruments. 65 (1994) 1094 - 1096