Penning source of hydrogen negative ions testing at different gases injection and optional application of ZrV cathodes

Abstract

A common challenge in hydrogen negative ions (H⁻ ions) production in a plasma volume is achieving the high concentration of vibrationally excited gas molecules. This study directly demonstrates the advantage of using the metal hydride based on ZrV alloy for H⁻ ions creation due to the hydrogen molecules releasing already in the vibrationally excited state. Using the Penning discharge with Zr₅₀V₅₀ cathodes driven at the low pressure (10 mPa) and the high voltage (5 kV) we have shown an almost doubling of extracted H⁻ current to 30 μA against to Cu cathodes at the same power of 10 W loaded in hydrogen plasma. Considering the tiny value (5 μA) of extracted negative current from the plasma generated on the gases (He, N₂, Ar) which cannot produce enough negative ions, the application of the metal hydride can improve the volume ionization and gas efficiency in existed negative ion source.