Characterization of a wall stabilized plasma window arc discharge and its impact on the transmission properties of heavy ion beams

Increasing particle beam energies and intensities in accelerator facilities around the world require a reliable technique for the separation of accelerator vacuum to high-pressurized target areas. While conventional techniques such as differential pumping stages or solid membranes may reach the limits of available lab space or their mechanical stability, a plasma window [1] represents a promising technique that allows for unobstructed ion beam transmission, simultaneously maintaining the required pressure gradient.

In 2018, the Plasma Physics department of Goethe University Frankfurt developed a prototype of a plasma window. It is based on a wall-stabilized, cascaded arc discharge and has since been optimized for its purpose as an active pressure separating transmission stage in particle accelerators. It operates at several kW of electrical input power, while allowing to control the pressure gradient in dependence of the flow rate and arc current.

As part of its further development, the plasma window has been successfully used to demonstrate the transmission of heavy ion beams, while maintaining the arc discharge for well over 10h in a single run. This contribution gives an insight into the operating conditions of the developed prototype with emphasis on its electrical, gaseous and plasma physical properties.

[1] Hershcovitch, A., J. Appl. Phys., AIP Publishing, 1995, 78, 5283