Photoelectron Emission from Metal Surfaces Induced by VUV-emission of Filament Driven Hydrogen Arc Discharge Plasma

TL;DR

This study measures photoelectron emission from metal surfaces induced by VUV radiation in a hydrogen plasma, revealing dependence on material and discharge power, with implications for plasma source efficiency.

Contribution

It provides the first quantitative analysis of photoelectron currents from various metals in a hydrogen arc discharge plasma, highlighting wavelength dependence and power scaling.

Findings

Photoelectron currents are similar across different metals.

Emission depends linearly on discharge power.

Significant emission occurs only at short wavelengths.

Abstract

Photoelectron emission measurements have been performed using a filament-driven multi-cusp arc discharge volume production H^- ion source (LIISA). It has been found that photoelectron currents obtained with Al, Cu, Mo, Ta and stainless steel (SAE 304) are on the same order of magnitude. The photoelectron currents depend linearly on the discharge power. It is shown experimentally that photoelectron emission is significant only in the short wavelength range of hydrogen spectrum due to the energy dependence of the quantum efficiency. It is estimated from the measured data that the maximum photoelectron flux from plasma chamber walls is on the order of 1 A per kW of discharge power.