Helyssen sources, different geometries for different needs

Cylindrical Plasma Sourcew5pwg+-RrgTLwqDUm52zZw

Conventional volumetric inductively coupled sources (ICP plasma source) are typically made of 3-4 turn solenoids. 

The number of turns is limited by competition between inductive and capacitive coupling between the coil and the plasma. The resulting plasma volume is thus reduced. Furthermore the generated plasma is located near the vessel edges. 

The patent-protected Helyssen cylindrical plasma source does not suffer from these limitations and allows large volume of plasma to be produced in the core of the discharge tube.

Additionally helicon waves can be very efficiently excited by Helyssen’s antenna.   Very high electron densities have been measured (typ. 1013 cm-3) in the pressure range as high as 10-1 mbar and even using high electronegative gases (SF6, O2,…) flow rates.  A reference article (Helyssen Circular_Toward_article_APhas been published in Journal of Applied Physics.

Main benefits are:

    • Large volume
    • Concentrated and very dense plasma
    • High pressure and high flow rates

Breakthrough in large area processing

Planar Plasma SourceLarge Planar ICP plasma source Helyssen

The patent-protected planar plasma source consists of a ladder type antenna with a unique concept that allows:

    • Much larger processing area compared to industry standard
    • High density and high uniformity of the generated plasma

QWUlwkJE3PdgKQiCqCXM4wThe resonating currents flowing in the plane antenna legs generate high and uniform electron densities. 

Usual large areas sources are either inductively or capacity coupled. Limitations are met in the attempt of up scaling because of power injection problems (very high current  / voltages into the matching elements and the feeding lines)

Helyssen antenna presents purely real impedance (typically close to 50 Ohm when coupled to the plasma) and thus independently of the antenna size. This enables convenient upscaling of the plasma source. The processed surfaces can be greatly extended based on requirements

Neutral beam injection with Helyssen’s plasma source for DEMO/Eurofusion project

Helicon discharge in the RAID device

Link to video